I can't start my android application. I'm using TableLayout in fragment_main.xml. And I think that problem somewhere in using it in code.
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/main_fragment"
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"
tools:context="com.nikolay.calculator.MainActivity$PlaceholderFragment" >
<TableRow
android:id="#+id/tableRow1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<EditText
android:id="#+id/firstNum"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="7"
android:hint="#string/hint1"
android:inputType="number|text" >
</EditText>
//....
<TableRow
android:id="#+id/tableRow5"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<TextView
android:id="#+id/textResult"
android:gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/textResult"
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="#+id/result"
android:gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/result"
android:textAppearance="?android:attr/textAppearanceLarge" />
</TableRow>
</TableLayout>
Here is my MainActivity class. In initWidget() method I set onclicklistener for all buttons and set my EditText and TextView fields. onCreate method was created by eclipse. I just added two last strings. Give only a piece of code.
public class MainActivity extends ActionBarActivity implements View.OnClickListener {
private CalcJavaLayer javaCalc;
private double a;
private double b;
private TableLayout table;
private EditText firstNum;
private EditText secondNum;
private TextView result;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
javaCalc = new CalcJavaLayer();
initWidgets();
}
private void initWidgets(){
table = (TableLayout) findViewById(R.id.main_fragment);
for(int i = 0; i < table.getChildCount(); i++){
TableRow row = (TableRow) table.getChildAt(i);
for(int j = 0; j < row.getChildCount(); j++){
if(row.getChildAt(j) instanceof Button){
Button button = (Button) row.getChildAt(j);
button.setOnClickListener(this);
}else if(row.getChildAt(j) instanceof EditText){
firstNum = (EditText) row.getChildAt(0);
secondNum = (EditText) row.getChildAt(1);
break;
}else if(row.getChildAt(j) instanceof TextView){
result = (TextView) row.getChildAt(1);
break;
}
}
}
}
And I receive next errors
05-20 14:45:35.649: E/AndroidRuntime(1701): FATAL EXCEPTION: main
05-20 14:45:35.649: E/AndroidRuntime(1701): Process: com.nikolay.calculator, PID: 1701
05-20 14:45:35.649: E/AndroidRuntime(1701): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.nikolay.calculator/com.nikolay.calculator.MainActivity}: java.lang.ClassCastException: android.support.v4.app.NoSaveStateFrameLayout cannot be cast to android.widget.TableLayout
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.app.ActivityThread.access$800(ActivityThread.java:135)
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.os.Handler.dispatchMessage(Handler.java:102)
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.os.Looper.loop(Looper.java:136)
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.app.ActivityThread.main(ActivityThread.java:5017)
05-20 14:45:35.649: E/AndroidRuntime(1701): at java.lang.reflect.Method.invokeNative(Native Method)
05-20 14:45:35.649: E/AndroidRuntime(1701): at java.lang.reflect.Method.invoke(Method.java:515)
05-20 14:45:35.649: E/AndroidRuntime(1701): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-20 14:45:35.649: E/AndroidRuntime(1701): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-20 14:45:35.649: E/AndroidRuntime(1701): at dalvik.system.NativeStart.main(Native Method)
05-20 14:45:35.649: E/AndroidRuntime(1701): Caused by: java.lang.ClassCastException: android.support.v4.app.NoSaveStateFrameLayout cannot be cast to android.widget.TableLayout
05-20 14:45:35.649: E/AndroidRuntime(1701): at com.nikolay.calculator.MainActivity.initWidgets(MainActivity.java:91)
05-20 14:45:35.649: E/AndroidRuntime(1701): at com.nikolay.calculator.MainActivity.onCreate(MainActivity.java:46)
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.app.Activity.performCreate(Activity.java:5231)
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
05-20 14:45:35.649: E/AndroidRuntime(1701): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
05-20 14:45:35.649: E/AndroidRuntime(1701): ... 11 more
searches in google have not yielded results. Appreciate any help!
Related
package kdev.circles;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final EditText ca = (EditText)findViewById(R.id.ca);
final EditText cp = (EditText)findViewById(R.id.cp);
final EditText sv = (EditText)findViewById(R.id.sv);
final EditText r = (EditText)findViewById(R.id.radius);
final TextView log = (TextView)findViewById(R.id.log);
Button clear = (Button)findViewById(R.id.clear);
Button solve = (Button)findViewById(R.id.Solve);
clear.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
ca.setText("");
cp.setText("");
sv.setText("");
r.setText("");
}
});
solve.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if((r.toString()).equals("")) {
log.setText(log.getText() + "\n" + "error, no value entered");
}else{
sv.setText(String.valueOf(Double.valueOf(String.valueOf(r.getText())) * Double.valueOf(String.valueOf(r.getText())) * Double.valueOf(String.valueOf(r.getText())) * 4 / 3 * 3.14159265));
cp.setText(String.valueOf(Double.valueOf(String.valueOf(r.getText()))*3.14159265*2));
ca.setText(String.valueOf(Double.valueOf(String.valueOf(r.getText()))*Double.valueOf(String.valueOf(r.getText()))*3.14159265));
log.setText(log.getText()+"\n"+"ca"+ca.getText()+"\n"+"sv"+sv.getText()+"\n"+"cp"+cp.getText());
}
}
});
}
#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);
}
}
xml file:
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Solve"
android:id="#+id/Solve"
android:width="100dp"
android:layout_alignParentBottom="true"
android:layout_alignEnd="#+id/sv" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="numberDecimal"
android:ems="10"
android:id="#+id/radius"
android:layout_alignParentTop="true"
android:layout_alignStart="#+id/editText" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="numberDecimal"
android:ems="10"
android:id="#+id/editText"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true"
android:layout_marginTop="49dp" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="numberDecimal"
android:ems="10"
android:id="#+id/editText2"
android:layout_below="#+id/editText"
android:layout_alignStart="#+id/editText" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="numberDecimal"
android:ems="10"
android:id="#+id/editText3"
android:layout_below="#+id/editText2"
android:layout_alignStart="#+id/editText2" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="circle's perimeter"
android:id="#+id/cp"
android:layout_above="#+id/editText2"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="circle's area"
android:id="#+id/ca"
android:layout_above="#+id/editText3"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="sphere's volume"
android:id="#+id/sv"
android:layout_alignBottom="#+id/editText3"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="radius"
android:id="#+id/textView3"
android:layout_alignBottom="#+id/radius"
android:layout_alignParentStart="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="clear"
android:id="#+id/clear"
android:layout_alignBottom="#+id/Solve"
android:layout_alignStart="#+id/editText3" />
<TextView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Large Text"
android:id="#+id/log"
android:layout_below="#+id/editText3"
android:layout_centerHorizontal="true"
android:layout_marginTop="57dp" />
Everything is working fine till i try opening it, i couldn't find the error, because my android virtual device wasn't connected to android studio properly. I am not sure what i should do. I did have another problem before but i realised that it was due to me using the findviewbyid function before the whole layout was loaded. I have solved that problem and tried a few different techniques to solve this problem but nothing worked.
When i try and run the app it just crashes, i am not sure why?
Any help will be usefull, thank you.
this is the logcat:
12-10 15:21:18.030 1907-1907/kdev.circles W/art﹕ Verification of java.lang.CharSequence android.support.v7.widget.ResourcesWrapper.getQuantityText(int, int) took 123.881364ms
12-10 15:21:18.520 1907-1907/kdev.circles D/AndroidRuntime﹕ Shutting down VM
12-10 15:21:18.520 1907-1907/kdev.circles E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: kdev.circles, PID: 1907
java.lang.RuntimeException: Unable to start activity ComponentInfo{kdev.circles/kdev.circles.MainActivity}: java.lang.ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.widget.EditText
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
Caused by: java.lang.ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.widget.EditText
at kdev.circles.MainActivity.onCreate(MainActivity.java:21)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
12-10 15:21:27.230 1907-1907/kdev.circles I/Process﹕ Sending signal. PID: 1907 SIG: 9
12-10 15:21:31.360 2153-2153/kdev.circles D/AndroidRuntime﹕ Shutting down VM
12-10 15:21:31.360 2153-2153/kdev.circles E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: kdev.circles, PID: 2153
java.lang.RuntimeException: Unable to start activity ComponentInfo{kdev.circles/kdev.circles.MainActivity}: java.lang.ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.widget.EditText
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
Caused by: java.lang.ClassCastException: android.support.v7.widget.AppCompatTextView cannot be cast to android.widget.EditText
at kdev.circles.MainActivity.onCreate(MainActivity.java:21)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
Check your view types in Java code and their matching id's in xml. They have to be of same type.
You have EditText in Java, but matching view id in xml is TextView
For instance:
final EditText ca = (EditText)findViewById(R.id.ca);
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="circle's area"
android:id="#+id/ca"
android:layout_above="#+id/editText3"
android:layout_alignParentStart="true" />
I have this code in my MainActivity class:
public class MainActivity extends ActionBarActivity {
Button mButton;
EditText mEdit;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mButton = (Button)findViewById(R.id.btnAsk);
mEdit = (EditText)findViewById(R.id.txtQuestion);
mButton.setOnClickListener(
new View.OnClickListener()
{
public void onClick(View view)
{
Toast.makeText(getApplicationContext(),
mEdit.getText().toString(), Toast.LENGTH_SHORT).show();
}
});
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
return rootView;
}
}
}
Everything was just fine, but after adding setOnClickListener() to mButton it started crashing at the very beginning.
Here is the error log:
04-26 14:12:26.255: E/AndroidRuntime(1447): FATAL EXCEPTION: main
04-26 14:12:26.255: E/AndroidRuntime(1447): Process: com.gelasoft.answeringball, PID: 1447
04-26 14:12:26.255: E/AndroidRuntime(1447): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.gelasoft.answeringball/com.gelasoft.answeringball.MainActivity}: java.lang.NullPointerException
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.app.ActivityThread.access$800(ActivityThread.java:135)
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.os.Handler.dispatchMessage(Handler.java:102)
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.os.Looper.loop(Looper.java:136)
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.app.ActivityThread.main(ActivityThread.java:5017)
04-26 14:12:26.255: E/AndroidRuntime(1447): at java.lang.reflect.Method.invokeNative(Native Method)
04-26 14:12:26.255: E/AndroidRuntime(1447): at java.lang.reflect.Method.invoke(Method.java:515)
04-26 14:12:26.255: E/AndroidRuntime(1447): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-26 14:12:26.255: E/AndroidRuntime(1447): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-26 14:12:26.255: E/AndroidRuntime(1447): at dalvik.system.NativeStart.main(Native Method)
04-26 14:12:26.255: E/AndroidRuntime(1447): Caused by: java.lang.NullPointerException
04-26 14:12:26.255: E/AndroidRuntime(1447): at com.gelasoft.answeringball.MainActivity.onCreate(MainActivity.java:30)
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.app.Activity.performCreate(Activity.java:5231)
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-26 14:12:26.255: E/AndroidRuntime(1447): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
04-26 14:12:26.255: E/AndroidRuntime(1447): ... 11 more
What am I missing here? I know that it is something really small, but I can't spot it right now.
P.S Here is my fragment xml:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.xx.ss.MainActivity$PlaceholderFragment" >
<ImageView
android:id="#+id/sphereIcon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:contentDescription="#string/magicBallDescr"
android:src="#drawable/ic_launcher" />
<LinearLayout
android:id="#+id/table"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#+id/sphereIcon"
android:orientation="vertical" >
<TextView
android:id="#+id/txtAnswer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
/>
<EditText
android:id="#+id/txtQuestion"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/textHint"
android:inputType="textMultiLine"
android:lines="8"
/>
<Button
android:id="#+id/btnAsk"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/btnAskQ"
android:paddingEnd="#dimen/activity_vertical_margin"
/>
</LinearLayout>
</RelativeLayout>
Replace
mButton = (Button)findViewById(R.id.btnAsk);
with
mButton = (Button)rootView.findViewById(R.id.btnAsk); // this will go in Fragment onCreateView
And move setOnClicklistener code as well to onCreateView.
Hope it helps.
Move this code :
mButton.setOnClickListener(
new View.OnClickListener()
{
public void onClick(View view)
{
Toast.makeText(getApplicationContext(),
mEdit.getText().toString(), Toast.LENGTH_SHORT).show();
}
});
into your fragment's onCreateView() method. It should work then.
I really don't know whats wrong with this...
The app should only change the text of the text view when clicking a button, in this case the start button.
When I start the app with the virtual machine it crashes.
My code
package com.example.projectiii;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
import android.os.Build;
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
Button btnS = (Button) findViewById(R.id.btStart);
btnS.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View view) {
// TODO Auto-generated method stub
TextView word = (TextView) findViewById(R.id.display);
word.setText("Project");
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
return rootView;
}
}
}
My 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: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.projectiii.MainActivity$PlaceholderFragment" >
<EditText
android:id="#+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/display"
android:layout_centerHorizontal="true"
android:layout_marginTop="46dp"
android:ems="10" >
<requestFocus />
</EditText>
<Button
android:id="#+id/btStart"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/text"
android:layout_below="#+id/text"
android:layout_marginTop="42dp"
android:text="Start" />
<Button
android:id="#+id/btFinish"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="#+id/btStart"
android:layout_alignRight="#+id/text"
android:text="Finish" />
<Chronometer
android:id="#+id/time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_alignRight="#+id/text"
android:layout_marginTop="40dp"
android:text="Chronometer" />
<TextView
android:id="#+id/display"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/time"
android:layout_centerHorizontal="true"
android:layout_marginTop="66dp"
android:text="Text"
android:textSize="30sp" />
My logcat
05-03 15:06:48.720: E/AndroidRuntime(921): FATAL EXCEPTION: main
05-03 15:06:48.720: E/AndroidRuntime(921): Process: com.example.projectiii, PID: 921
05-03 15:06:48.720: E/AndroidRuntime(921): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.projectiii/com.example.projectiii.MainActivity}: java.lang.NullPointerException
05-03 15:06:48.720: E/AndroidRuntime(921): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
05-03 15:06:48.720: E/AndroidRuntime(921): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
05-03 15:06:48.720: E/AndroidRuntime(921): at android.app.ActivityThread.access$800(ActivityThread.java:135)
05-03 15:06:48.720: E/AndroidRuntime(921): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
05-03 15:06:48.720: E/AndroidRuntime(921): at android.os.Handler.dispatchMessage(Handler.java:102)
05-03 15:06:48.720: E/AndroidRuntime(921): at android.os.Looper.loop(Looper.java:136)
05-03 15:06:48.720: E/AndroidRuntime(921): at android.app.ActivityThread.main(ActivityThread.java:5017)
05-03 15:06:48.720: E/AndroidRuntime(921): at java.lang.reflect.Method.invokeNative(Native Method)
05-03 15:06:48.720: E/AndroidRuntime(921): at java.lang.reflect.Method.invoke(Method.java:515)
05-03 15:06:48.720: E/AndroidRuntime(921): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
05-03 15:06:48.720: E/AndroidRuntime(921): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
05-03 15:06:48.720: E/AndroidRuntime(921): at dalvik.system.NativeStart.main(Native Method)
05-03 15:06:48.720: E/AndroidRuntime(921): Caused by: java.lang.NullPointerException
05-03 15:06:48.720: E/AndroidRuntime(921): at com.example.projectiii.MainActivity.onCreate(MainActivity.java:33)
05-03 15:06:48.720: E/AndroidRuntime(921): at android.app.Activity.performCreate(Activity.java:5231)
05-03 15:06:48.720: E/AndroidRuntime(921): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
05-03 15:06:48.720: E/AndroidRuntime(921): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
05-03 15:06:48.720: E/AndroidRuntime(921): ... 11 more
05-03 15:06:48.760: W/ActivityManager(385): Force finishing activity com.example.projectiii/.MainActivity
Make sure the xml you posted is activity_main, not fragment_main. You don't need a Fragment here, so remove all Fragment-related code.
Bind the view of TextView here:
setContentView(R.layout.activity_main);
TextView word = (TextView) findViewById(R.id.display);
the layout xml you have shown is of the fragment(since it doesn't contain the R.id. container). You are trying to access the button element defined in your Fragment layout in your activity which is giving you he null pointer. Try accessing the button from the fragment class which will resolve your error.
in the last few days I tried to develop android applications with no success, for some reason my application keep crashing.
the application keeps throwing few exceptions that I didn't succeeded to handle with.
MainActivity.java :
package com.mobIce.digicoin.digitalcoin;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends ActionBarActivity {
private List<Coin> coins;
public MainActivity(){
coins = new ArrayList<Coin>();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment())
.commit();
populateCoins();
populateListView();
}
}
private void populateCoins() {
coins.add(new Coin("Bitcoin", "650", "4", "http://coinmarketcap.com/img/Bitcoin.png"));
coins.add(new Coin("Dogecoin", "100", "400", "http://coinmarketcap.com/img/Bitcoin.png"));
coins.add(new Coin("fafaf", "8065", "400", "http://coinmarketcap.com/img/Bitcoin.png"));
}
private void populateListView() {
ArrayAdapter<Coin> adapter = new MyListAdapter();
ListView list = (ListView) findViewById(R.id.coinsListView);
list.setAdapter(adapter);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.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();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
return rootView;
}
}
private class MyListAdapter extends ArrayAdapter<Coin> {
public MyListAdapter()
{
super(MainActivity.this, R.layout.coin_layout, coins);
}
#Override
public View getView(int position, View convertView, ViewGroup parent){
View itemView = convertView;
if(itemView == null)
itemView = getLayoutInflater().inflate(R.layout.coin_layout, parent, false);
//find the coin to work with.
Coin currentCoin = coins.get(position);
//fill the view
try{
TextView coinName = (TextView) itemView.findViewById(R.id.coinName);
coinName.setText(currentCoin.getName());
TextView coinPrice = (TextView) itemView.findViewById(R.id.coinPrice);
coinPrice.setText(currentCoin.getPrice());
TextView coinPercentage = (TextView) itemView.findViewById(R.id.coinPercentage);
coinPercentage.setText(currentCoin.getPercentage());
}
catch (NullPointerException e){ }
return itemView;
}
}
}
activity_main.xml:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.mobIce.digicoin.digitalcoin.MainActivity"
tools:ignore="MergeRootFrame" />
fragment_main.xml:
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
xmlns:android="http://schemas.android.com/apk/res/android">
<ListView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/coinsListView"
android:paddingLeft="30dp" />
</LinearLayout>
coin_layout.xml:
<?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"
android:padding="8dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="coinName"
android:id="#+id/coinName"
android:layout_alignParentTop="true"
android:layout_toRightOf="#+id/coinIcon"
android:layout_marginTop="35dp"
android:layout_marginLeft="20dp" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/coinIcon"
android:maxHeight="80dp"
android:maxWidth="80dp"
android:minHeight="80dp"
android:minWidth="80dp"
android:src="#drawable/dogecoin"
android:longClickable="false"
android:focusable="false"
android:focusableInTouchMode="false"
android:baselineAlignBottom="false"
android:clickable="false"
android:adjustViewBounds="true"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Large Text"
android:id="#+id/coinPrice"
android:layout_marginLeft="35dp"
android:layout_alignTop="#+id/coinIcon"
android:layout_toRightOf="#+id/coinName"
android:layout_marginTop="25dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Medium Text"
android:id="#+id/coinPercentage"
android:layout_below="#+id/coinPrice"
android:layout_alignLeft="#+id/coinPrice"
android:layout_alignStart="#+id/coinPrice" />
</RelativeLayout>
logcat trace:
03-17 08:59:33.977 1107-1107/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 08:59:33.977 1107-1107/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 08:59:33.987 1107-1107/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1107
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:47)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:36)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:04:09.857 1149-1149/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 09:04:09.857 1149-1149/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 09:04:09.867 1149-1149/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1149
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:50)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:39)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:06:36.697 1192-1192/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 09:06:36.697 1192-1192/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 09:06:36.717 1192-1192/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1192
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:50)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:39)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:13:38.647 1239-1239/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 09:13:38.647 1239-1239/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 09:13:38.747 1239-1239/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1239
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:50)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:37)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:13:45.127 1239-1239/com.mobIce.digicoin.digitalcoin I/Process﹕ Sending signal. PID: 1239 SIG: 9
03-17 09:19:34.847 1285-1285/com.mobIce.digicoin.digitalcoin D/AndroidRuntime﹕ Shutting down VM
03-17 09:19:34.847 1285-1285/com.mobIce.digicoin.digitalcoin W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xb1a38ba8)
03-17 09:19:34.857 1285-1285/com.mobIce.digicoin.digitalcoin E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mobIce.digicoin.digitalcoin, PID: 1285
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mobIce.digicoin.digitalcoin/com.mobIce.digicoin.digitalcoin.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.mobIce.digicoin.digitalcoin.MainActivity.populateListView(MainActivity.java:50)
at com.mobIce.digicoin.digitalcoin.MainActivity.onCreate(MainActivity.java:37)
at android.app.Activity.performCreate(Activity.java:5231)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
at android.app.ActivityThread.access$800(ActivityThread.java:135)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
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:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
03-17 09:20:11.987 1285-1285/com.mobIce.digicoin.digitalcoin I/Process﹕ Sending signal. PID: 1285 SIG: 9
Your coinsListView is in the fragment layout and not in activity layout. You cannot access it with findViewById() in populateListView() called from activity onCreate(). Instead, move the list view population to the fragment's onCreateView() after the inflation, calling findViewById() on the rootView layout you just inflated.
I'm Trying to set a different Class for Specs on my TabHost, but i had only some errors (log pasted below)
If i change my champ.setIndicator("Champion").setContent(R.id.tab1); and so on for the other tabs it works.
Could someone help me?
MY code:
TabsMain.java
package com.girardi.lolguides;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.widget.TabHost;
import android.widget.TabHost.TabSpec;
public class TabsMain extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tabs_main);
TabHost tabHost = (TabHost) findViewById(R.id.tabhost);
tabHost.setup();
TabSpec champ = tabHost.newTabSpec("champ");
TabSpec equip = tabHost.newTabSpec("item");
champ.setIndicator("Champion").setContent(new Intent(this, Champion.class));
equip.setIndicator("Items").setContent(new Intent(this, Equip.class));
tabHost.addTab(champ);
tabHost.addTab(equip);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.tabs_main, menu);
return true;
}
}
Champion.java
package com.girardi.lolguides;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class Champion extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
/* First Tab Content */
TextView textView = new TextView(this);
textView.setText("First Tab");
setContentView(textView);
}
}
Equip.java
package com.girardi.lolguides;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class Equip extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
/* Second Tab Content */
TextView textView = new TextView(this);
textView.setText("Second Tab");
setContentView(textView);
}
}
activity_tabs_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: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=".TabsMain" >
<TabHost
android:id="#+id/tabhost"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TabWidget
android:id="#android:id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" >
</TabWidget>
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<LinearLayout
android:id="#+id/tab1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
</LinearLayout>
<LinearLayout
android:id="#+id/tab2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
</LinearLayout>
<LinearLayout
android:id="#+id/tab3"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
</LinearLayout>
</FrameLayout>
</LinearLayout>
</TabHost>
</RelativeLayout>
LOG:
05-20 13:51:22.890: D/AndroidRuntime(22816): Shutting down VM
05-20 13:51:22.890: W/dalvikvm(22816): threadid=1: thread exiting with uncaught exception (group=0x40e832a0)
05-20 13:51:22.910: E/AndroidRuntime(22816): FATAL EXCEPTION: main
05-20 13:51:22.910: E/AndroidRuntime(22816): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.girardi.lolguides/com.girardi.lolguides.TabsMain}: java.lang.NullPointerException
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100)
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.app.ActivityThread.access$600(ActivityThread.java:140)
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.os.Handler.dispatchMessage(Handler.java:99)
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.os.Looper.loop(Looper.java:137)
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.app.ActivityThread.main(ActivityThread.java:4898)
05-20 13:51:22.910: E/AndroidRuntime(22816): at java.lang.reflect.Method.invokeNative(Native Method)
05-20 13:51:22.910: E/AndroidRuntime(22816): at java.lang.reflect.Method.invoke(Method.java:511)
05-20 13:51:22.910: E/AndroidRuntime(22816): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
05-20 13:51:22.910: E/AndroidRuntime(22816): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
05-20 13:51:22.910: E/AndroidRuntime(22816): at dalvik.system.NativeStart.main(Native Method)
05-20 13:51:22.910: E/AndroidRuntime(22816): Caused by: java.lang.NullPointerException
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.widget.TabHost.addTab(TabHost.java:243)
05-20 13:51:22.910: E/AndroidRuntime(22816): at com.girardi.lolguides.TabsMain.onCreate(TabsMain.java:23)
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.app.Activity.performCreate(Activity.java:5206)
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1083)
05-20 13:51:22.910: E/AndroidRuntime(22816): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)
05-20 13:51:22.910: E/AndroidRuntime(22816): ... 11 more
05-20 13:53:10.655: D/AndroidRuntime(24134): Shutting down VM
05-20 13:53:10.655: W/dalvikvm(24134): threadid=1: thread exiting with uncaught exception (group=0x40e832a0)
05-20 13:53:10.665: E/AndroidRuntime(24134): FATAL EXCEPTION: main
05-20 13:53:10.665: E/AndroidRuntime(24134): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.girardi.lolguides/com.girardi.lolguides.TabsMain}: java.lang.NullPointerException
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100)
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.app.ActivityThread.access$600(ActivityThread.java:140)
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.os.Handler.dispatchMessage(Handler.java:99)
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.os.Looper.loop(Looper.java:137)
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.app.ActivityThread.main(ActivityThread.java:4898)
05-20 13:53:10.665: E/AndroidRuntime(24134): at java.lang.reflect.Method.invokeNative(Native Method)
05-20 13:53:10.665: E/AndroidRuntime(24134): at java.lang.reflect.Method.invoke(Method.java:511)
05-20 13:53:10.665: E/AndroidRuntime(24134): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
05-20 13:53:10.665: E/AndroidRuntime(24134): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
05-20 13:53:10.665: E/AndroidRuntime(24134): at dalvik.system.NativeStart.main(Native Method)
05-20 13:53:10.665: E/AndroidRuntime(24134): Caused by: java.lang.NullPointerException
05-20 13:53:10.665: E/AndroidRuntime(24134): at com.girardi.lolguides.TabsMain.onCreate(TabsMain.java:19)
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.app.Activity.performCreate(Activity.java:5206)
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1083)
05-20 13:53:10.665: E/AndroidRuntime(24134): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)
05-20 13:53:10.665: E/AndroidRuntime(24134): ... 11 more
Your activity should extend TabActivity (which is deprecated) or use Fragments (which is the right way) to use tabs. See TabActivity for more informations and examples.
EDIT: about layout you can use a relativeLayout like this:
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<ListView android:id="#+id/list"
android:layout_alignParentBottom="true"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
<android.support.v4.app.TabHost
android:id="#android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_above="#+id/footerlist"
android:layout_alignParentTop="true">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TabWidget
android:id="#android:id/tabs"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0"/>
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_weight="0"/>
<FrameLayout
android:id="#+id/realtabcontent"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
</LinearLayout>
</TabHost>
</RelativeLayout>
About MainActivity:
public class MainActivity extends android.support.v4.app.FragmentActivity {
private android.support.v4.app.FragmentTabHost mTabHost;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTabHost = (FragmentTabHost)findViewById(android.R.id.tabhost);
mTabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);
mTabHost.addTab(...);
}
}