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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" />

Android - Trying to instantiate a class that is not a fragment

So I'm trying to create a fragment in my app that contains a toolbar (as an action bar) using appcompat activity so I can reuse it across multiple views.
I've tested a simple text-only fragment using a class that extends fragment only and got that to work, but to include a toolbar I need to extend AppCompatActivity in the view (I think).
When I try to get this to work, I get an error that says that my action_bar_fragment is not a Fragment.
I fell like I'm missing something basic here. Any ideas?
Main Activity:
package com.example.aaron.personaldataassistant;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.content.Intent;
import android.support.v7.widget.Toolbar;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.view.Menu;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// action_bar_fragment = (Toolbar) findViewById(R.id.action_bar_fragment);
// setSupportActionBar(action_bar_fragment);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater mi=getMenuInflater();
mi.inflate(R.menu.action_bar, menu);
return super.onCreateOptionsMenu(menu);
}
Main Activity Layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:id="#+id/activity_main"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.aaron.personaldataassistant.MainActivity">
<fragment
android:id="#+id/action_bar_fragment"
android:layout_width="wrap_content"
android:layout_height="match_parent"
class="com.example.aaron.personaldataassistant.action_bar_fragment"
tools:layout="#layout/action_bar_fragment" />
</LinearLayout>
Action Bar Fragment:
package com.example.aaron.personaldataassistant;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
public class action_bar_fragment extends AppCompatActivity {
public action_bar_fragment() {
}
Toolbar action_bar;
#Nullable
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.action_bar_fragment, container, false);
}
#Override
protected void onCreate (Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.action_bar_fragment);
action_bar = (Toolbar) findViewById(R.id.action_bar);
setSupportActionBar(action_bar);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater mi = getMenuInflater();
mi.inflate(R.menu.action_bar, menu);
return super.onCreateOptionsMenu(menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
int i = item.getItemId();
if (i == R.id.item1) {
Toast.makeText(action_bar_fragment.this, "Item 1", Toast.LENGTH_SHORT).show();
} else if (i == R.id.item2) {
Toast.makeText(action_bar_fragment.this, "Item 2", Toast.LENGTH_SHORT).show();
} else if (i == R.id.item3) {
Toast.makeText(action_bar_fragment.this, "Item 3", Toast.LENGTH_SHORT).show();
}
//replace toasts with desired actions: Settings, Help and Exit. Settigns is blank, help is context-dependent, exit gives possibility to exit
return super.onOptionsItemSelected(item);
}
}
Fragment Layout:
<FrameLayout 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"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context="layout.Fragment_1">
<!-- TODO: Update blank fragment layout -->
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="#string/hello_blank_fragment" />
<android.support.v7.widget.Toolbar
android:id="#+id/action_bar"
android:layout_width="300dp"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimaryDark"
android:elevation="8dp"
android:theme="#style/ThemeOverlay.AppCompat.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
/>
</FrameLayout>
And of course the error message:
--------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.aaron.personaldataassistant, PID: 2481
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.aaron.personaldataassistant/com.example.aaron.personaldataassistant.MainActivity}: android.view.InflateException: Binary XML file line #19: Binary XML file line #19: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Caused by: android.view.InflateException: Binary XML file line #19: Binary XML file line #19: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #19: Error inflating class fragment
Caused by: android.app.Fragment$InstantiationException: Trying to instantiate a class com.example.aaron.personaldataassistant.action_bar_fragment that is not a Fragment
at android.app.Fragment.instantiate(Fragment.java:617)
at android.app.Fragment.instantiate(Fragment.java:593)
at android.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2302)
at android.app.FragmentController.onCreateView(FragmentController.java:98)
at android.app.Activity.onCreateView(Activity.java:5884)
at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:36)
at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:75)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:777)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:858)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821)
at android.view.LayoutInflater.inflate(LayoutInflater.java:518)
at android.view.LayoutInflater.inflate(LayoutInflater.java:426)
at android.view.LayoutInflater.inflate(LayoutInflater.java:377)
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:284)
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
at com.example.aaron.personaldataassistant.MainActivity.onCreate(MainActivity.java:24)
at android.app.Activity.performCreate(Activity.java:6662)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
at android.app.ActivityThread.-wrap12(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Caused by: java.lang.ClassCastException
at android.app.Fragment.instantiate(Fragment.java:618)
at android.app.Fragment.instantiate(Fragment.java:593) 
at android.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2302) 
at android.app.FragmentController.onCreateView(FragmentController.java:98) 
at android.app.Activity.onCreateView(Activity.java:5884) 
at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:36) 
at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:75) 
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:777) 
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727) 
at android.view.LayoutInflater.rInflate(LayoutInflater.java:858) 
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:518) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:426) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:377) 
at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:284) 
at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:140) 
at com.example.aaron.personaldataassistant.MainActivity.onCreate(MainActivity.java:24) 
at android.app.Activity.performCreate(Activity.java:6662) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) 
at android.app.ActivityThread.-wrap12(ActivityThread.java) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:154) 
at android.app.ActivityThread.main(ActivityThread.java:6077) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 
Application terminated.
Thank you for your time.
UPDATE
This is great, the top answer helped me figure out that doing things in a fragment can require different methods than doing them in an Activity. Googling "How do I do X in a fragment" turned out to give me almost everything I needed. There is only one problem left now: I changed the Action Bar Fragment line 37 to
setHasOptionsMenu(true);
action_bar = (Toolbar) getView().findViewById(R.id.action_bar);
This is giving me a null object reference, but the layout definitely exists! Any idea what's going on?
The relevant part of the error message is:
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.View.findViewById(int)' on a null object reference
Sorry for the long delay getting back to you, I had work. Should be faster this time!
I will also clean up the comment I made on your reply.

This is because your intended fragment is not a Fragment but an Activity, where:
action_bar_fragment extends AppCompatActivity {
}
is an Activity, so you should be extends action_bar_fragment with Fragment:
action_bar_fragment extends Fragment {
}
And please change your code style, where action_bar_fragment should be something like ActionBarFragment. A class name should be started with uppercase.
Please read Creating and Using Fragments.

I came upon this question because of the main title "Trying to instantiate a class that is not a Fragment". So maybe my solution can help. I'm using Android Studio 2.2.3 and targeting API 15.
I got that error:
...
Caused by: android.app.Fragment$InstantiationException: Trying to instantiate a class com.xyz.tuv.MyFragment that is not a Fragment
because I was importing:
import android.support.v4.app.Fragment;
instead of
import android.app.Fragment;
Since API 11, you can use a regular activity (android.app.Activity) for inserting fragments as documented here. But in that case you also have to use android.app.Fragment, contrary to what the main example shows.

In your MainActivity class, you have to change the order of some of code, they are:
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater mi=getMenuInflater();
mi.inflate(R.menu.action_bar, menu);
return super.onCreateOptionsMenu(menu);
}
Change it to :
#Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
MenuInflater mi = getMenuInflater();
mi.inflate(R.menu.action_bar, menu);
return true;
}
and try again.

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
}
});

Android studio crossfade drawables crashes app

I am trying to make basic app that crossfades one image for another and then back again.
The app however keeps crashing when I click the first image.
The crossfade method fade works on it's own. It has just begun crashing since I added the second method to transition the images back.
I see the InvocationTargetException and the NullPointerException but I don't understand how/why this is happening.
Also the onClick within the content setup is set to the correct methods.
package com.example.richardcurteis.layoutdemo;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ImageView;
public class MainActivity extends AppCompatActivity {
ImageView obama;
ImageView will;
public void fade(View view) {
obama = (ImageView) findViewById(R.id.obama);
will = (ImageView) findViewById(R.id.will);
obama.animate().alpha(0f).setDuration(2000);
will.animate().alpha(1f).setDuration(2000);
}
public void fadeBack(View view) {
will.animate().alpha(1f).setDuration(2000);
obama.animate().alpha(0f).setDuration(2000);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
#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);
}
}
Activity Main xml:
<?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.example.richardcurteis.layoutdemo.MainActivity"
tools:showIn="#layout/activity_main"
android:clickable="false">
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/obama"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"
android:src="#drawable/obama"
android:onClick="fade" />
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="#+id/will"
android:layout_alignTop="#+id/obama"
android:layout_alignParentStart="true"
android:src="#drawable/will"
android:alpha="0"
android:onClick="fadeBack" />
</RelativeLayout>
Errors:
12-29 17:17:32.003 3368-3368/com.example.richardcurteis.layoutdemo E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.richardcurteis.layoutdemo, PID: 3368
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:275)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:270)
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.ViewPropertyAnimator android.widget.ImageView.animate()' on a null object reference
at com.example.richardcurteis.layoutdemo.MainActivity.fadeBack(MainActivity.java:29)
at java.lang.reflect.Method.invoke(Native Method) 
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:270) 
at android.view.View.performClick(View.java:5198) 
at android.view.View$PerformClick.run(View.java:21147) 
at android.os.Handler.handleCallback(Handler.java:739) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:148) 
at android.app.ActivityThread.main(ActivityThread.java:5417) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

You are initializing views obama and will only in fade(). If fadeBack() is called before fade() values of obama and will are both null. That's why you are getting a null pointer exception.
Move this code from fade() to onCreate(),
obama = (ImageView) findViewById(R.id.obama);
will = (ImageView) findViewById(R.id.will);
So that it will get initiated at the time of view creation itself.
MainActivity should look like this :
public class MainActivity extends AppCompatActivity {
ImageView obama;
ImageView will;
public void fade(View view) {
obama.animate().alpha(0f).setDuration(2000);
will.animate().alpha(1f).setDuration(2000);
}
public void fadeBack(View view) {
will.animate().alpha(1f).setDuration(2000);
obama.animate().alpha(0f).setDuration(2000);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
obama = (ImageView) findViewById(R.id.obama);
will = (ImageView) findViewById(R.id.will);
......
}
......
}

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) {}
}