Android bug - Binary XML file line #1: Error inflating class fragment - java

I am attempting to implement a to-do list using listview and listview adapter but have run into several runtime exceptions that I can't overcome. Logcat says that I am trying to invoke findViewById on a null object reference (line 24 = private Spinner spinner_priority;). However, the id for the spinner is spinnerPriority and findViewById(R.id.spinnerPriority) is invoked correctly.
I haven't changed the default ToDoActivity.java implementation except for extending ToDoActivity from FragmentActivity instead of AppCombatActivity and importing android.support.v4.app.FragmentActivity instead of android.app.FragmentActivity.
Any insights as to why the app is crashing?
Logcat:
08-27 00:45:58.209 11873-11873/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.ttse.final_tse, PID: 11873
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.ttse.final_tse/com.ttse.final_tse.ToDoActivity}: android.view.InflateException: Binary XML file line #1: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: android.view.InflateException: Binary XML file line #1: Error inflating class fragment
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:763)
at android.view.LayoutInflater.inflate(LayoutInflater.java:482)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:378)
at android.app.Activity.setContentView(Activity.java:2145)
at com.ttse.final_tse.ToDoActivity.onCreate(ToDoActivity.java:14)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
            at android.app.ActivityThread.access$800(ActivityThread.java:151)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5254)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.support.v4.app.FragmentActivity.findViewById(int)' on a null object reference
at com.ttse.final_tse.ToDoActivityFragment.<init>(ToDoActivityFragment.java:24)
at java.lang.reflect.Constructor.newInstance(Native Method)
at java.lang.Class.newInstance(Class.java:1606)
at android.support.v4.app.Fragment.instantiate(Fragment.java:421)
at android.support.v4.app.Fragment.instantiate(Fragment.java:396)
at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2162)
at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:300)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:482)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
            at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:378)
            at android.app.Activity.setContentView(Activity.java:2145)
            at com.ttse.final_tse.ToDoActivity.onCreate(ToDoActivity.java:14)
            at android.app.Activity.performCreate(Activity.java:5990)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
            at android.app.ActivityThread.access$800(ActivityThread.java:151)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:135)
            at android.app.ActivityThread.main(ActivityThread.java:5254)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
ToDoActivity.java
package com.ttse.final_tse;
import android.support.v4.app.FragmentActivity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class ToDoActivity extends FragmentActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_to_do);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_to_do, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
activity_to_do.xml
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/fragment"
android:name="com.ttse.final_tse.ToDoActivityFragment"
tools:layout="#layout/fragment_to_do"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
ToDoActivityFragment.java
package com.ttse.final_tse;
import android.app.DialogFragment;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class ToDoActivityFragment extends Fragment {
private List<Task> list_tasks = new ArrayList<Task>();
private ArrayAdapter<Task> list_adapter = null;
private final EditText editText_title = (EditText)getActivity().findViewById(R.id.editTextTitle);
private Spinner spinner_priority;
private Button button_datepicker;
private final TextView textView_date = (TextView)getActivity().findViewById(R.id.textViewDate);
private EditText editText_shortDescr;
private Button button_save;
public ToDoActivityFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_to_do, container, false);
}
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// To-Do ListView
ListView list = (ListView)getActivity().findViewById(R.id.listViewToDo);
list_adapter = new ArrayAdapter<Task>(getActivity(), android.R.layout.simple_list_item_1, list_tasks);
list.setAdapter(list_adapter);
// Priority Spinner
spinner_priority = (Spinner)getActivity().findViewById(R.id.spinnerPriority);
ArrayAdapter<CharSequence> spinner_adapter = ArrayAdapter.createFromResource(getActivity(), R.array.priority_array, android.R.layout.simple_spinner_item);
spinner_adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner_priority.setAdapter(spinner_adapter);
spinner_priority.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
// Datepicker Button
button_datepicker = (Button)getActivity().findViewById(R.id.buttonDatepicker);
button_datepicker.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
showDatePickerDialog(v);
}
});
// Short Description EditText
editText_shortDescr = (EditText)getActivity().findViewById(R.id.editTextShortDescr);
// Save Button
button_save = (Button)getActivity().findViewById(R.id.buttonSave);
button_save.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(TextUtils.isEmpty(editText_title.getText()) || TextUtils.isEmpty(textView_date.getText())) {
Toast.makeText(getActivity(), "Please set to-do title and due date", Toast.LENGTH_SHORT).show();
return;
}
onSave();
}
});
}
private void showDatePickerDialog(View v) {
DialogFragment date_picker = new DatePickerFragment();
// show datepicker fragment on screen
date_picker.show(getActivity().getFragmentManager(), "datePicker");
}
private void onSave() {
Task task = new Task();
task.setTitle(editText_title.getText().toString());
task.setPriority(spinner_priority.getSelectedItem().toString());
task.setDueDate(textView_date.getText().toString());
task.setShortDescr(editText_shortDescr.getText().toString());
list_adapter.add(task);
list_adapter.notifyDataSetChanged();
}
}
fragment_to_do.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin"
tools:context=".ToDoActivityFragment">
<ListView
android:id="#+id/listViewToDo"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="10">
</ListView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:orientation="vertical"
android:layout_weight="7">
<EditText
android:id="#+id/editTextTitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Title..."/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="3"
android:text="Priority Level:"
android:layout_marginTop="5dp"/>
<Spinner
android:id="#+id/spinnerPriority"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="4"
android:spinnerMode="dropdown"
android:layout_marginTop="5dp"/>
<LinearLayout
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="4"
android:orientation="vertical">
<Button
android:id="#+id/buttonDatepicker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="#string/pick_date"/>
<TextView
android:id="#+id/textViewDate"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"/>
</LinearLayout>
</LinearLayout>
<EditText
android:id="#+id/editTextShortDescr"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Short description..."
android:textSize="14sp"/>
<Button
android:id="#+id/buttonSave"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/text_save"
android:layout_gravity="center"/>
</LinearLayout>
</LinearLayout>
DatePickerFragment.java
package com.ttse.final_tse;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.os.Bundle;
import android.widget.DatePicker;
import android.widget.TextView;
import java.util.Calendar;
public class DatePickerFragment extends DialogFragment
implements DatePickerDialog.OnDateSetListener {
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final Calendar c = Calendar.getInstance();
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);
return new DatePickerDialog(getActivity(), this, year, month, day);
}
public void onDateSet(DatePicker view, int year, int month, int day) {
TextView textView_date = (TextView)getActivity().findViewById(R.id.textViewDate);
textView_date.setText(new StringBuilder()
.append(month + 1).append("/").append(day).append("/")
.append(year));
}
}
Task.java
package com.ttse.final_tse;
public class Task {
private String mTitle;
private String mDueDate;
private String mPriority;
private String mShortDescr;
public String getTitle() {
return mTitle;
}
public void setTitle(String title) {
mTitle = title;
}
public String getDueDate() {
return mDueDate;
}
public void setDueDate(String dueDate) {
mDueDate = dueDate;
}
public String getPriority() {
return mPriority;
}
public void setPriority(String priority) {
mPriority = priority;
}
public String getShortDescr() {
return mShortDescr;
}
public void setShortDescr(String shortDescr) {
mShortDescr = shortDescr;
}
}

update your code like this
private EditText editText_title ;
private TextView textView_date ;
initialize in onActivityCreated
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// To-Do ListView
editText_title = (EditText)getActivity().findViewById(R.id.editTextTitle);
textView_date = (TextView)getActivity().findViewById(R.id.textViewDate);

Related

Physical Device only - Google Maps - 'File.mkdir()' on a null object reference

I am running my code and getting this error when using app on mobile devide, but on emulator it is working.
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.nirbhaym.Indoor, PID: 17543
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.nirbhaym.Indoor/com.example.nirbhaym.indoor.MapsActivity}: android.view.InflateException: Binary XML file line #62: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2335)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2397)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1310)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5268)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
Caused by: android.view.InflateException: Binary XML file line #62: Error inflating class fragment
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:763)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:806)
at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:256)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109)
at com.example.nirbhaym.indoor.MapsActivity.onCreate(MapsActivity.java:50)
at android.app.Activity.performCreate(Activity.java:6033)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2288)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2397) 
at android.app.ActivityThread.access$800(ActivityThread.java:151) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1310) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:135) 
at android.app.ActivityThread.main(ActivityThread.java:5268) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.io.File.mkdir()' on a null object reference
at com.google.maps.api.android.lib6.gmm6.m.ad.a(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.c.h.a(Unknown Source)
at com.google.maps.api.android.lib6.gmm6.c.y.a(Unknown Source)
at com.google.maps.api.android.lib6.e.bd.a(Unknown Source)
at com.google.maps.api.android.lib6.e.ev.a(Unknown Source)
at com.google.maps.api.android.lib6.e.z.a(Unknown Source)
at com.google.maps.api.android.lib6.e.y.a(Unknown Source)
at com.google.android.gms.maps.internal.u.onTransact(SourceFile:107)
at android.os.Binder.transact(Binder.java:380)
at com.google.android.gms.maps.internal.IMapFragmentDelegate$zza$zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment$zza.onCreateView(Unknown Source)
at com.google.android.gms.dynamic.zza$4.zzb(Unknown Source)
at com.google.android.gms.dynamic.zza.zza(Unknown Source)
at com.google.android.gms.dynamic.zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment.onCreateView(Unknown Source)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1036)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1226)
at android.support.v4.app.FragmentManagerImpl.addFragment(FragmentManager.java:1328)
at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2284)
at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:111)
at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:314)
at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:31)
at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:79)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:733)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:806) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:504) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:414) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:365) 
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:256) 
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109) 
at com.example.nirbhaym.indoor.MapsActivity.onCreate(MapsActivity.java:50) 
at android.app.Activity.performCreate(Activity.java:6033) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2288) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2397) 
at android.app.ActivityThread.access$800(ActivityThread.java:151) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1310) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:135) 
at android.app.ActivityThread.main(ActivityThread.java:5268) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697) 
I/Process: Sending signal. PID: 17543 SIG: 9
Application terminated.
Main activity code
package com.example.nirbhaym.indoor;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptor;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.GroundOverlay;
import com.google.android.gms.maps.model.GroundOverlayOptions;
import com.google.android.gms.maps.model.LatLng;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.CheckBox;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import java.util.ArrayList;
import java.util.List;
/**
* This shows how to add a ground overlay to a map.
*/
public class MapsActivity extends AppCompatActivity
implements OnSeekBarChangeListener, OnMapReadyCallback,
GoogleMap.OnGroundOverlayClickListener {
private static final int TRANSPARENCY_MAX = 100;
private static final LatLng NEWARK = new LatLng(28.544594, 77.272486);
private static final LatLng NEAR_NEWARK =
new LatLng(NEWARK.latitude - 0.001, NEWARK.longitude - 0.025);
private final List<BitmapDescriptor> mImages = new ArrayList<BitmapDescriptor>();
private GroundOverlay mGroundOverlay;
private GroundOverlay mGroundOverlayRotated;
private SeekBar mTransparencyBar;
private int mCurrentEntry = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout);
mTransparencyBar = (SeekBar) findViewById(R.id.transparencySeekBar);
mTransparencyBar.setMax(TRANSPARENCY_MAX);
mTransparencyBar.setProgress(0);
SupportMapFragment mapFragment =
(SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
#Override
public void onMapReady(GoogleMap map) {
// Register a listener to respond to clicks on GroundOverlays.
map.setOnGroundOverlayClickListener(this);
map.moveCamera(CameraUpdateFactory.newLatLngZoom(NEWARK, 11));
mImages.clear();
mImages.add(BitmapDescriptorFactory.fromResource(R.drawable.fourth_floor_app));
//mImages.add(BitmapDescriptorFactory.fromResource(R.drawable.newark_prudential_sunny));
// Add a small, rotated overlay that is clickable by default
// (set by the initial state of the checkbox.)
mGroundOverlayRotated = map.addGroundOverlay(new GroundOverlayOptions()
.image(mImages.get(0)).anchor(0, 1)
.position(NEAR_NEWARK, 4300f, 3025f)
.bearing(30)
.clickable(((CheckBox) findViewById(R.id.toggleClickability)).isChecked()));
// Add a large overlay at Newark on top of the smaller overlay.
mGroundOverlay = map.addGroundOverlay(new GroundOverlayOptions()
.image(mImages.get(mCurrentEntry)).anchor(0, 1)
.position(NEWARK, 8600f, 6500f));
mTransparencyBar.setOnSeekBarChangeListener(this);
// Override the default content description on the view, for accessibility mode.
// Ideally this string would be localised.
map.setContentDescription("Google Map with ground overlay.");
}
#Override
public void onStopTrackingTouch(SeekBar seekBar) {
}
#Override
public void onStartTrackingTouch(SeekBar seekBar) {
}
#Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
if (mGroundOverlay != null) {
mGroundOverlay.setTransparency((float) progress / (float) TRANSPARENCY_MAX);
}
}
public void switchImage(View view) {
mCurrentEntry = (mCurrentEntry + 1) % mImages.size();
mGroundOverlay.setImage(mImages.get(mCurrentEntry));
}
/**
* Toggles the visibility between 100% and 50% when a {#link GroundOverlay} is clicked.
*/
#Override
public void onGroundOverlayClick(GroundOverlay groundOverlay) {
// Toggle transparency value between 0.0f and 0.5f. Initial default value is 0.0f.
mGroundOverlayRotated.setTransparency(0.5f - mGroundOverlayRotated.getTransparency());
}
/**
* Toggles the clickability of the smaller, rotated overlay based on the state of the View that
* triggered this call.
* This callback is defined on the CheckBox in the layout for this Activity.
*/
public void toggleClickability(View view) {
if (mGroundOverlayRotated != null) {
mGroundOverlayRotated.setClickable(((CheckBox) view).isChecked());
}
}
}
Layout file
<?xml version="1.0" encoding="utf-8"?><!--
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/fourth_floor_app"
android:padding="5dp">
<TextView
android:id="#+id/transparency_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:text="string/transparency" />
<SeekBar
android:id="#+id/transparencySeekBar"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_toEndOf="#+id/transparency_text"
android:layout_toRightOf="#+id/transparency_text" />
<Button
android:id="#+id/switchImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/transparencySeekBar"
android:onClick="switchImage"
android:text="string/switch_image" />
<CheckBox
android:id="#+id/toggleClickability"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/switchImage"
android:layout_toEndOf="#+id/switchImage"
android:layout_toRightOf="#+id/switchImage"
android:checked="true"
android:onClick="toggleClickability"
android:text="string/clickable" />
</RelativeLayout>
<fragment
android:id="#+id/map"
class="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
FragmentManager fmanager = getSupportFragmentManager();
Fragment fragment = fmanager.findFragmentById(R.id.map);
SupportMapFragment supportmapfragment = (SupportMapFragment)fragment;
GoogleMap supportMap = supportmapfragment.getMap();
try this code. For this the tutorial is here hope this helps you. The problem is in fragment only. You need to check permissions also in above tutorial. Hope it helps you
http://www.truiton.com/2013/05/android-supportmapfragment-example/
EDIT:
Check permission for External Storage:
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Class not found when unmarshalling: android.support.v7.widget.Toolbar$SavedState

i am using Maps API to create a simple android app and i get a wierd error i can't solve. It usually happens when i rotate my device. I'm using google services 8.4.0
4-23 15:39:47.503 9419-9419/com.licenta.vladut.mmap E/Parcel: Class not found when unmarshalling: android.support.v7.widget.Toolbar$SavedState
java.lang.ClassNotFoundException: android.support.v7.widget.Toolbar$SavedState
at java.lang.Class.classForName(Native Method)
at java.lang.Class.forName(Class.java:308)
at android.os.Parcel.readParcelableCreator(Parcel.java:2275)
at android.os.Parcel.readParcelable(Parcel.java:2239)
at android.os.Parcel.readValue(Parcel.java:2146)
at android.os.Parcel.readSparseArrayInternal(Parcel.java:2540)
at android.os.Parcel.readSparseArray(Parcel.java:1868)
at android.os.Parcel.readValue(Parcel.java:2203)
at android.os.Parcel.readArrayMapInternal(Parcel.java:2479)
at android.os.BaseBundle.unparcel(BaseBundle.java:221)
at android.os.Bundle.getBundle(Bundle.java:782)
at com.google.android.gms.maps.internal.ao.a(:com.google.android.gms.alldynamite:74)
at maps.ei.bu.a(Unknown Source)
at maps.ei.n.a(Unknown Source)
at com.google.android.gms.maps.internal.i$a.onTransact(:com.google.android.gms.alldynamite:107)
at android.os.Binder.transact(Binder.java:380)
at com.google.android.gms.maps.internal.IMapFragmentDelegate$zza$zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment$zza.onCreateView(Unknown Source)
at com.google.android.gms.dynamic.zza$4.zzb(Unknown Source)
at com.google.android.gms.dynamic.zza.zza(Unknown Source)
at com.google.android.gms.dynamic.zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment.onCreateView(Unknown Source)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1974)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1036)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1230)
at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2315)
at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120)
at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:357)
at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:31)
at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:80)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:733)
at android.view.LayoutInflater.inflate(LayoutInflater.java:482)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:276)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:136)
at com.licenta.vladut.mmap.MainActivity.onCreate(MainActivity.java:54)
at android.app.Activity.performCreate(Activity.java:6020)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2259)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2368)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3947)
at android.app.ActivityThread.access$900(ActivityThread.java:149)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1290)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5292)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)
Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.v7.widget.Toolbar$SavedState" on path: DexPathList[[zip file "/data/data/com.google.android.gms/app_chimera/m/00000000/DynamiteModules-prod.apk"],nativeLibraryDirectories=[/data/data/com.google.android.gms/app_chimera/m/00000000/n/armeabi-v7a, /vendor/lib, /system/lib]]
at dalvik.system.BaseDexClassLoader.f
04-23 15:39:47.503 9419-9419/com.licenta.vladut.mmap D/AndroidRuntime: Shutting down VM
04-23 15:39:47.505 9419-9419/com.licenta.vladut.mmap E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.licenta.vladut.mmap, PID: 9419
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.licenta.vladut.mmap/com.licenta.vladut.mmap.MainActivity}: android.view.InflateException: Binary XML file line #2: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2306)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2368)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3947)
at android.app.ActivityThread.access$900(ActivityThread.java:149)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1290)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5292)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703)
Caused by: android.view.InflateException: Binary XML file line #2: Error inflating class fragment
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:763)
at android.view.LayoutInflater.inflate(LayoutInflater.java:482)
at android.view.LayoutInflater.inflate(LayoutInflater.java:414)
at android.view.LayoutInflater.inflate(LayoutInflater.java:365)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:276)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:136)
at com.licenta.vladut.mmap.MainActivity.onCreate(MainActivity.java:54)
at android.app.Activity.performCreate(Activity.java:6020)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2259)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2368) 
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3947) 
at android.app.ActivityThread.access$900(ActivityThread.java:149) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1290) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:135) 
at android.app.ActivityThread.main(ActivityThread.java:5292) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:908) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:703) 
Caused by: android.os.BadParcelableException: ClassNotFoundException when unmarshalling: android.support.v7.widget.Toolbar$SavedState
at android.os.Parcel.readParcelableCreator(Parcel.java:2289)
at android.os.Parcel.readParcelable(Parcel.java:2239)
at android.os.Parcel.readValue(Parcel.java:2146)
at android.os.Parcel.readSparseArrayInternal(Parcel.java:2540)
at android.os.Parcel.readSparseArray(Parcel.java:1868)
at android.os.Parcel.readValue(Parcel.java:2203)
at android.os.Parcel.readArrayMapInternal(Parcel.java:2479)
at android.os.BaseBundle.unparcel(BaseBundle.java:221)
at android.os.Bundle.getBundle(Bundle.java:782)
at com.google.android.gms.maps.internal.ao.a(:com.google.android.gms.alldynamite:74)
at maps.ei.bu.a(Unknown Source)
at maps.ei.n.a(Unknown Source)
at com.google.android.gms.maps.internal.i$a.onTransact(:com.google.android.gms.alldynamite:107)
at android.os.Binder.transact(Binder.java:380)
at com.google.android.gms.maps.internal.IMapFragmentDelegate$zza$zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment$zza.onCreateView(Unknown Source)
at com.google.android.gms.dynamic.zza$4.zzb(Unknown Source)
at com.google.android.gms.dynamic.zza.zza(Unknown Source)
at com.google.android.gms.dynamic.zza.onCreateView(Unknown Source)
at com.google.android.gms.maps.SupportMapFragment.onCreateView(Unknown Source)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:1974)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1036)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1230)
at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2315)
at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120)
at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:357)
at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:31)
at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:80)
at android.view.LayoutInf
My MainActivity.java is
package com.licenta.vladut.mmap;
import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.support.v4.app.ActivityCompat;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Toast;
import com.google.android.gms.appindexing.AppIndex;
import com.google.android.gms.auth.api.Auth;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.ResultCallback;
import com.google.android.gms.common.api.Status;
import com.google.android.gms.maps.CameraUpdate;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
public class MainActivity extends AppCompatActivity implements GoogleApiClient.OnConnectionFailedListener, OnMapReadyCallback {
GoogleMap mMap;
private static final double BM_LAT = 47.6595076, BM_LNG = 23.5631243;
private Toolbar toolbar;
private GoogleApiClient mGoogleApiClient;
private static final String TAG = "SignInActivity";
private static final int ERROR_DIALOG_REQUEST = 9001;
private static final int RC_SIGN_IN = 9002;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
.requestEmail()
.build();
mGoogleApiClient = new GoogleApiClient.Builder(this)
.enableAutoManage(this /* FragmentActivity */, this /* OnConnectionFailedListener */)
.addApi(Auth.GOOGLE_SIGN_IN_API, gso)
.addApi(AppIndex.API).build();
if (checkPlayServices()) {
setContentView(R.layout.activity_map);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
(MainActivity.this).setSupportActionBar(toolbar);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
} else {
setContentView(R.layout.activity_main);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.sign_out) {
signOut();
return true;
}
return super.onOptionsItemSelected(item);
}
private void signOut() {
Auth.GoogleSignInApi.signOut(mGoogleApiClient).setResultCallback(
new ResultCallback<Status>() {
#Override
public void onResult(Status status) {
toSignIn();
}
});
}
private void toSignIn() {
Intent i = new Intent(this, SignInActivity.class);
startActivity(i);
}
#Override
public void onConnectionFailed(ConnectionResult connectionResult) {
// An unresolvable error has occurred and Google APIs (including Sign-In) will not
// be available.
Log.d(TAG, getString(R.string.onConnectionFailed) + connectionResult);
}
private boolean checkPlayServices() {
GoogleApiAvailability googleAPI = GoogleApiAvailability.getInstance();
int result = googleAPI.isGooglePlayServicesAvailable(this);
if (result != ConnectionResult.SUCCESS) {
if (googleAPI.isUserResolvableError(result)) {
googleAPI.getErrorDialog(this, result,
ERROR_DIALOG_REQUEST).show();
} else {
Toast.makeText(this, "Nu se poate conecta la Google Play Services!", Toast.LENGTH_SHORT).show();
}
return false;
}
return true;
}
#Override
public void onMapReady(final GoogleMap map) {
this.mMap = map;
gotoLocation(BM_LAT,BM_LNG,18);
}
private void gotoLocation(double lat, double lng, float zoom){
LatLng latLng = new LatLng(lat, lng);
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(latLng,zoom);
mMap.moveCamera(update);
}
}
Activity_main.xml is
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="match_parent"
tools:context="com.licenta.vladut.mmap.MainActivity">
<include
android:id="#+id/toolbar"
layout="#layout/toolbar"
/>
</RelativeLayout>
activity_map.xml is
<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include
android:id="#+id/toolbar"
layout="#layout/toolbar"
/>
</fragment>
and finally, toolbar.xml is
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.Toolbar
android:background="?attr/colorPrimary"
android:id="#+id/toolbar"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:minHeight="?attr/actionBarSize"
android:layout_width="match_parent"
android:layout_alignParentStart="true"
android:elevation="4dp"
app:popupTheme="#style/AppTheme.PopupOverlay"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:android="http://schemas.android.com/apk/res/android">
</android.support.v7.widget.Toolbar>
I didn't like provided solutions as it imposed on my layouts and architecture.
Here's what I did to make it work. If you look at your stacktrace the ClassNotFoundException is coming from the line on GoogleMaps. So if we just fix that, the issue is gone.
GoogleMaps pukes/throw an error when the savedInstanceState has other items in it besides it's own. The solution is to just give GoogleMaps it's own dedicated bundle.
// class property
private static final String KEY_MAP_SAVED_STATE = "mapState";
// class methods
#Override
public void onViewCreated(View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
mapView = findMapView(); // make your own method here
Bundle mapState = (savedInstanceState != null)
? savedInstanceState.getBundle(KEY_MAP_SAVED_STATE): null;
mapView.onCreate(mapState);
}
#Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
Bundle mapState = new Bundle();
mapView.onSaveInstanceState(mapState);
outState.putBundle(KEY_MAP_SAVED_STATE, mapState);
}
One thing to note is I'm not using the SupportMapFragment. I'm using a MapView directly. You may have to extend the SupportMapFragment so you can catch the hook methods and provide a blank/clean bundle
Upon rotation, your SupportMapFragment gets destroyed and recreated. Before it's destroyed, it writes its current state to a Parcel, to be used in restoring its state when recreated. The Fragment's saved state will include the state of its child Views, and since you've nested a Toolbar within it, it attempts to save and restore that, as well. The Toolbar class does not have an inner class SavedState necessary for that, so this process fails when trying to restore the Toolbar instance from the Parcel.
The solution is to not nest the Toolbar - or any other View, for that matter - within the <fragment> element. Instead, pull the <include> out of the <fragment>, and put them both in another ViewGroup; for example, a vertical LinearLayout, or a RelativeLayout.
Changing activity_map.xml to this worked, thanks again Mike.
<?xml version="1.0" encoding="utf-8" ?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<include
android:id="#+id/toolbar"
layout="#layout/toolbar" />
<fragment xmlns:map="http://schemas.android.com/apk/res-auto"
android:id="#+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent">
</fragment>
</RelativeLayout>
I had a similar problem with my custom view and found this solution.
I noticed that this crash occurred when I extended RecyclerView or AppCompatSpinner and needed to save the state. The crash will probably happen for other views as well.
Basically the crash is caused by a bug in AbsSavedState as mentioned here.
And the crash only occurs when the constructor of the SavedState is called without a class loader. It seemed like this was an old issue however I started getting crash reports for Android 9 and 10.
So the fix was to change:
public SavedState(Parcel source) {
super(source);
//...
}
to:
public SavedState(Parcel source) {
super(source, LinearLayoutManager.class.getClassLoader());
//...
}
Edit
I was on the right track, but then I was looking at some Android code and found out that there was actually a constructor missing that caused the crash. So I had the following constructor for the SavedState:
SavedState(Parcel in)
{
super(in);
//...
}
And I needed to add the following:
#RequiresApi(Build.VERSION_CODES.N)
SavedState(Parcel in, ClassLoader loader)
{
super(in, loader);
//...
}
And then I needed to change the creator:
public static final Creator<SavedState> CREATOR = new ClassLoaderCreator<SavedState>()
{
#Override
public SavedState createFromParcel(Parcel source, ClassLoader loader)
{
return Build.VERSION.SDK_INT >= Build.VERSION_CODES.N ? new SavedState(source, loader) : new SavedState(source);
}
#Override
public SavedState createFromParcel(Parcel source)
{
return createFromParcel(source, null);
}
public SavedState[] newArray(int size)
{
return new SavedState[size];
}
};

I have just started android development and when i was making this app it didnt work while debugging

This app is all about clicking a Button and there is a TextBox which changes its content when clicked.
MainActivity.java
package com.lost.eventhandling;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
Button willybutton=(Button)findViewById(R.id.willybutton);
assert willybutton != null;
willybutton.setOnClickListener(
new Button.OnClickListener(){
public void onClick(View v){
TextView willytext=(TextView)findViewById(R.id.willytext);
willytext.setText("I DID IT ");
}
}
);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
Now for xml code I had
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:context="com.lost.eventhandling.MainActivity"
android:background="#71f8bd">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="#string/willy_text"
android:id="#+id/willytext"
android:textColor="#e83858"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="179dp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/willy_button"
android:id="#+id/willybutton"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:background="#764045"/>
</RelativeLayout>
Whenever I debug my application it sends a message it unfortuantely stopped.
And my android monitor gives me this red coloured text:
FATAL EXCEPTION: main
Process: com.lost.eventhandling, PID: 2449
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.lost.eventhandling/com.lost.eventhandling.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
at com.lost.eventhandling.MainActivity.onCreate(MainActivity.java:26)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) 
at android.app.ActivityThread.access$800(ActivityThread.java:151) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:135) 
at android.app.ActivityThread.main(ActivityThread.java:5254) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 
Replace yours OnclickListener code of Button with these lines of code:
Button willybutton=(Button)findViewById(R.id.willybutton);
TextView willytext=(TextView)findViewById(R.id.willytext);
willybutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
/////PERFORM YOURS OPERATION HERE
}
});

TabHost addTabs on Android crashes the apk

I have a problem that I can not solve, the problem TabHost that crashes when apk run,I've been trying hard for this but still can not, please help.
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin" tools:context=".MainActivity">
<TabHost
android:id="#android:id/tabhost"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<TabWidget
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="#android:id/tabs"
android:layout_gravity="bottom"></TabWidget>
<FrameLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="bottom"
android:id="#android:id/tabcontent"></FrameLayout>
</LinearLayout>
</TabHost>
</RelativeLayout>
MainActivity.java
package com.example.asus.smartcity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.content.Intent;
import android.widget.TabHost;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TabHost tabhostku = (TabHost)findViewById(android.R.id.tabhost);
tabhostku.setup();
TabHost.TabSpec spec;
Intent intent;
intent = new Intent().setClass(this, MapActivity.class);
spec = tabhostku.newTabSpec("map");
spec.setIndicator("map",null);
spec.setContent(intent);
tabhostku.addTab(spec);
intent = new Intent().setClass(this, PlaceActivity.class);
spec = tabhostku.newTabSpec("place");
spec.setIndicator("place",null);
spec.setContent(intent);
tabhostku.addTab(spec);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
MapActivity.java
import android.app.Activity;
import android.os.Bundle;
/**
* Created by Asus on 11-Nov-15.
*/
public class MapActivity extends Activity{
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.map);
}
}
PlaceActivity.java
package com.example.asus.smartcity;
import android.os.Bundle;
import android.app.ListActivity;
import android.widget.ArrayAdapter;
/**
* Created by Asus on 11-Nov-15.
*/
public class PlaceActivity extends ListActivity {
String []placeku={"KBS","Surabaya Carnival","Kebun Bibit"};
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.place);
setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1,placeku));
}
}
Logcat
11-11 12:51:22.153 19591-19591/? I/art﹕ Late-enabling -Xcheck:jni
11-11 12:51:22.223 19591-19591/com.example.asus.smartcity W/ResourceType﹕ For resource 0x01040529, entry index(1321) is beyond type entryCount(1)
11-11 12:51:22.287 19591-19591/com.example.asus.smartcity W/ResourceType﹕ For resource 0x0104007b, entry index(123) is beyond type entryCount(1)
11-11 12:51:22.288 19591-19591/com.example.asus.smartcity W/ResourceType﹕ For resource 0x01040077, entry index(119) is beyond type entryCount(1)
11-11 12:51:22.314 19591-19591/com.example.asus.smartcity W/ResourceType﹕ For resource 0x0104007b, entry index(123) is beyond type entryCount(1)
11-11 12:51:22.318 19591-19591/com.example.asus.smartcity D/AndroidRuntime﹕ Shutting down VM
11-11 12:51:22.320 19591-19591/com.example.asus.smartcity E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.asus.smartcity, PID: 19591
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.asus.smartcity/com.example.asus.smartcity.MainActivity}: java.lang.IllegalStateException: Did you forget to call 'public void setup(LocalActivityManager activityGroup)'?
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2379)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2442)
at android.app.ActivityThread.access$800(ActivityThread.java:156)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1351)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:211)
at android.app.ActivityThread.main(ActivityThread.java:5371)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:945)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:740)
Caused by: java.lang.IllegalStateException: Did you forget to call 'public void setup(LocalActivityManager activityGroup)'?
at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:754)
at android.widget.TabHost.setCurrentTab(TabHost.java:420)
at android.widget.TabHost.addTab(TabHost.java:247)
at com.example.asus.smartcity.MainActivity.onCreate(MainActivity.java:29)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2332)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2442)
            at android.app.ActivityThread.access$800(ActivityThread.java:156)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1351)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:211)
            at android.app.ActivityThread.main(ActivityThread.java:5371)
            at java.lang.reflect.Method.invoke(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:372)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:945)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:740)
11-11 12:51:25.717 19591-19591/com.example.asus.smartcity I/Process﹕ Sending signal. PID: 19591 SIG: 9
You have to change extends AppCompatActivity to ActivityGroup After that change
tabhostku.setup();
to
tabhostku.setup(this.getLocalActivityManager());
Try this,
Change,
tabhostku.setup();
to
mlam = new LocalActivityManager(this, false);
tabhostku.setup(mlam );
And in onPause and onResume add the following code.
#Override
public void onPause() {
super.onPause();
try {
mlam.dispatchPause(isFinishing());
} catch (Exception e) {}
}
#Override
public void onResume() {
super.onResume();
try {
mlam.dispatchResume();
} catch (Exception e) {}
}

RecyclerView app crash

I have a problem when I'm trying to use a RecyclerView. The app crashes directly on launch.
Here is the error in logcat:
`Process: com.test.alvar.temadagar, PID: 14522
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.alvar.temadagar/com.test.alvar.temadagar.Temadagar} : android.view.InflateException: Binary XML file line #182: Error inflating class RecyclerView
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5086)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.view.InflateException: Binary XML file line #182: Error inflating class RecyclerView
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:707)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:758)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:758)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:249)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:106)
at com.test.alvar.temadagar.Temadagar.onCreate(Temadagar.java:73)
at android.app.Activity.performCreate(Activity.java:5248)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5086)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
 at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.ClassNotFoundException: Didn't find class "android.view.RecyclerView" on path: DexPathList[[zip file "/data/app/com.test.alvar.temadagar-2.apk"],nativeLibraryDirectories=[/data/app-lib/com.test.alvar.temadagar-2, /vendor/lib, /system/lib]]
at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
at android.view.LayoutInflater.createView(LayoutInflater.java:559)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:652)
at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:66)
at android.view.LayoutInflater.onCreateView(LayoutInflater.java:669)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:694)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:758)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:758)
at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:249)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:106)
at com.test.alvar.temadagar.Temadagar.onCreate(Temadagar.java:73)
at android.app.Activity.performCreate(Activity.java:5248)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2162)
 at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5086)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)`
</pre>
Temadagar.java (Main activity)
package com.test.alvar.temadagar;
import android.os.Build;
import android.os.Bundle;
import android.support.v4.app.ActivityOptionsCompat;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import java.util.ArrayList;
import android.os.StrictMode;
import android.util.Log;
public class Temadagar extends AppCompatActivity {
private RecyclerView mRecyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_temadagar);
StrictMode.enableDefaults(); //STRICT MODE ENABLED
mRecyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(this);
mRecyclerView.setLayoutManager(mLayoutManager);
mAdapter = new MyRecyclerViewAdapter(getDataSet());
mRecyclerView.setAdapter(mAdapter);
}
#Override
protected void onResume() {
super.onResume();
((MyRecyclerViewAdapter) mAdapter).setOnItemClickListener(new
MyRecyclerViewAdapter.MyClickListener() {
#Override
public void onItemClick(int position, View v) {
// Log.i(LOG_TAG, " Clicked on Item " + position);
}
});
}
private ArrayList<DataObject> getDataSet() {
ArrayList results = new ArrayList<DataObject>();
for (int index = 0; index < 20; index++) {
DataObject obj = new DataObject("Some Primary Text " + index,
"Secondary " + index);
results.add(index, obj);
}
return results;
}
}
DataObject.java
package com.test.alvar.temadagar;
public class DataObject {
private String mText1;
private String mText2;
DataObject (String text1, String text2){
mText1 = text1;
mText2 = text2;
}
public String getmText1() {
return mText1;
}
public void setmText1(String mText1) {
this.mText1 = mText1;
}
public String getmText2() {
return mText2;
}
public void setmText2(String mText2) {
this.mText2 = mText2;
}
}
MyRecyclerViewAdapter.java
package com.test.alvar.temadagar;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
public class MyRecyclerViewAdapter extends RecyclerView
.Adapter<MyRecyclerViewAdapter
.DataObjectHolder> {
private static String LOG_TAG = "MyRecyclerViewAdapter";
private ArrayList<DataObject> mDataset;
private static MyClickListener myClickListener;
public static class DataObjectHolder extends RecyclerView.ViewHolder
implements View
.OnClickListener {
TextView label;
TextView dateTime;
public DataObjectHolder(View itemView) {
super(itemView);
label = (TextView) itemView.findViewById(R.id.textView);
dateTime = (TextView) itemView.findViewById(R.id.textView2);
Log.i(LOG_TAG, "Adding Listener");
itemView.setOnClickListener(this);
}
#Override
public void onClick(View v) {
myClickListener.onItemClick(getPosition(), v);
}
}
public void setOnItemClickListener(MyClickListener myClickListener) {
this.myClickListener = myClickListener;
}
public MyRecyclerViewAdapter(ArrayList<DataObject> myDataset) {
mDataset = myDataset;
}
#Override
public DataObjectHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
View view = LayoutInflater.from(parent.getContext())
.inflate(R.layout.list_item, parent, false);
DataObjectHolder dataObjectHolder = new DataObjectHolder(view);
return dataObjectHolder;
}
#Override
public void onBindViewHolder(DataObjectHolder holder, int position) {
holder.label.setText(mDataset.get(position).getmText1());
holder.dateTime.setText(mDataset.get(position).getmText2());
}
public void addItem(DataObject dataObj, int index) {
mDataset.add(dataObj);
notifyItemInserted(index);
}
public void deleteItem(int index) {
mDataset.remove(index);
notifyItemRemoved(index);
}
#Override
public int getItemCount() {
return mDataset.size();
}
public interface MyClickListener {
public void onItemClick(int position, View v);
}
}
list_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="?android:attr/selectableItemBackground"
android:orientation="vertical">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingTop="5dp"
android:text="Large Text"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="5dp"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:text="Small Text"
android:textAppearance="?android:attr/textAppearanceSmall" />
</LinearLayout>
activity_temdagar.xml (main)
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
android:layout_height="match_parent"
android:layout_width="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#+id/coming_text"
android:id="#+id/my_recycler_view"/>
</RelativeLayout>
you have to use <android.support.v7.widget.RecyclerView in your activity_temdagar.xml, not <RecyclerView. The widget is only part of the support library

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