I am doing the Android Development Tutorial My First App. After doing the action bar class, I have problems running the app on my emulator. There are no errors on any of my files (java or xml). Yet, the very first red line in my logcat is "04-03 15:49:37.597: E/AndroidRuntime(1115): FATAL EXCEPTION: main". I have researched all previous posts about Fatal Exceptions, and have not found my answer yet. Please help me. My Main Activity java file is:
package com.example.myfirstapp2;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
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.EditText;
public class MainActivity extends ActionBarActivity {
public final static String EXTRA_MESSAGE = "com.example.myfirstapp2.MESSAGE";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_displaymessage);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
// If your miniSdkVersion is 11 or higher, instead use:
// getActionBar().setDisplayHomeAsUpEnabled(true);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new PlaceholderFragment()).commit();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu items for use in the action bar
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main_activity_actions, menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int itemId = item.getItemId();
if (itemId == R.id.action_search) {
openSearch();
return true;
} else if (itemId == R.id.action_settings) {
openSettings();
return true;
} else {
return super.onOptionsItemSelected(item);
}
}
private void openSettings() {
// TODO Auto-generated method stub
}
private void openSearch() {
// TODO Auto-generated method stub
}
/**
* 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;
}
}
/**Called when the user clicks the Send button */
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
My Main Activity xml is:
<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.example.myfirstapp2.MainActivity"
tools:ignore="MergeRootFrame" />
My Display Message Activity Java file is:
package com.example.myfirstapp2;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class DisplayMessageActivity extends ActionBarActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the message from the intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
// Set the text view as the activity layout
setContentView(textView);
}
@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_display_message,
container, false);
return rootView;
}
}
}
My fragment_display_message xml is:
<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.myfirstapp2.DisplayMessageActivity$PlaceholderFragment" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
</RelativeLayout>
My activity_display_message xml is:
<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.example.myfirstapp2.DisplayMessageActivity"
tools:ignore="MergeRootFrame" />
My fragment_main xml is:
<LinearLayout 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:orientation="horizontal" >
<EditText android:id="@+id/edit_message"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:hint="@string/edit_message"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button_send"
android:onClick="sendMessage" />
</LinearLayout>
My logcat is:
04-03 15:49:37.577: D/AndroidRuntime(1115): Shutting down VM
04-03 15:49:37.577: W/dalvikvm(1115): threadid=1: thread exiting with uncaught exception (group=0xb1abdba8)
04-03 15:49:37.597: E/AndroidRuntime(1115): FATAL EXCEPTION: main
04-03 15:49:37.597: E/AndroidRuntime(1115): Process: com.example.myfirstapp2, PID: 1115
04-03 15:49:37.597: E/AndroidRuntime(1115): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myfirstapp2/com.example.myfirstapp2.MainActivity}: java.lang.NullPointerException
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.app.ActivityThread.access$800(ActivityThread.java:135)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.os.Handler.dispatchMessage(Handler.java:102)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.os.Looper.loop(Looper.java:136)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.app.ActivityThread.main(ActivityThread.java:5017)
04-03 15:49:37.597: E/AndroidRuntime(1115): at java.lang.reflect.Method.invokeNative(Native Method)
04-03 15:49:37.597: E/AndroidRuntime(1115): at java.lang.reflect.Method.invoke(Method.java:515)
04-03 15:49:37.597: E/AndroidRuntime(1115): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-03 15:49:37.597: E/AndroidRuntime(1115): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-03 15:49:37.597: E/AndroidRuntime(1115): at dalvik.system.NativeStart.main(Native Method)
04-03 15:49:37.597: E/AndroidRuntime(1115): Caused by: java.lang.NullPointerException
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.view.ViewGroup.addViewInner(ViewGroup.java:3561)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.view.ViewGroup.addView(ViewGroup.java:3415)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.view.ViewGroup.addView(ViewGroup.java:3391)
04-03 15:49:37.597: E/AndroidRuntime(1115): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:309)
04-03 15:49:37.597: E/AndroidRuntime(1115): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:299)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.app.Activity.setContentView(Activity.java:1949)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.support.v7.app.ActionBarActivity.superSetContentView(ActionBarActivity.java:220)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.support.v7.app.ActionBarActivityDelegateICS.setContentView(ActionBarActivityDelegateICS.jav a:106)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:81)
04-03 15:49:37.597: E/AndroidRuntime(1115): at com.example.myfirstapp2.MainActivity.onCreate(MainActivity.java:20)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.app.Activity.performCreate(Activity.java:5231)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-03 15:49:37.597: E/AndroidRuntime(1115): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
04-03 15:49:37.597: E/AndroidRuntime(1115): ... 11 more
04-03 15:49:42.597: I/Process(1115): Sending signal. PID: 1115 SIG: 9
04-03 15:50:36.957: D/AndroidRuntime(1135): Shutting down VM
04-03 15:50:36.957: W/dalvikvm(1135): threadid=1: thread exiting with uncaught exception (group=0xb1abdba8)
04-03 15:50:36.977: E/AndroidRuntime(1135): FATAL EXCEPTION: main
04-03 15:50:36.977: E/AndroidRuntime(1135): Process: com.example.myfirstapp2, PID: 1135
04-03 15:50:36.977: E/AndroidRuntime(1135): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myfirstapp2/com.example.myfirstapp2.MainActivity}: java.lang.NullPointerException
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.app.ActivityThread.access$800(ActivityThread.java:135)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.os.Handler.dispatchMessage(Handler.java:102)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.os.Looper.loop(Looper.java:136)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.app.ActivityThread.main(ActivityThread.java:5017)
04-03 15:50:36.977: E/AndroidRuntime(1135): at java.lang.reflect.Method.invokeNative(Native Method)
04-03 15:50:36.977: E/AndroidRuntime(1135): at java.lang.reflect.Method.invoke(Method.java:515)
04-03 15:50:36.977: E/AndroidRuntime(1135): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-03 15:50:36.977: E/AndroidRuntime(1135): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-03 15:50:36.977: E/AndroidRuntime(1135): at dalvik.system.NativeStart.main(Native Method)
04-03 15:50:36.977: E/AndroidRuntime(1135): Caused by: java.lang.NullPointerException
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.view.ViewGroup.addViewInner(ViewGroup.java:3561)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.view.ViewGroup.addView(ViewGroup.java:3415)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.view.ViewGroup.addView(ViewGroup.java:3391)
04-03 15:50:36.977: E/AndroidRuntime(1135): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:309)
04-03 15:50:36.977: E/AndroidRuntime(1135): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:299)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.app.Activity.setContentView(Activity.java:1949)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.support.v7.app.ActionBarActivity.superSetContentView(ActionBarActivity.java:220)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.support.v7.app.ActionBarActivityDelegateICS.setContentView(ActionBarActivityDelegateICS.jav a:106)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:81)
04-03 15:50:36.977: E/AndroidRuntime(1135): at com.example.myfirstapp2.MainActivity.onCreate(MainActivity.java:20)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.app.Activity.performCreate(Activity.java:5231)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-03 15:50:36.977: E/AndroidRuntime(1135): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
04-03 15:50:36.977: E/AndroidRuntime(1135): ... 11 more
04-03 15:50:41.527: I/Process(1135): Sending signal. PID: 1135 SIG: 9
04-03 15:54:55.657: D/AndroidRuntime(1174): Shutting down VM
04-03 15:54:55.657: W/dalvikvm(1174): threadid=1: thread exiting with uncaught exception (group=0xb1abdba8)
04-03 15:54:55.687: E/AndroidRuntime(1174): FATAL EXCEPTION: main
04-03 15:54:55.687: E/AndroidRuntime(1174): Process: com.example.myfirstapp2, PID: 1174
04-03 15:54:55.687: E/AndroidRuntime(1174): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myfirstapp2/com.example.myfirstapp2.MainActivity}: java.lang.NullPointerException
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
04-03 15:54:55.687: E/AndroidRuntime(1174): at 04-03 15:54:55.687: E/AndroidRuntime(1174): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.os.Handler.dispatchMessage(Handler.java:102)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.os.Looper.loop(Looper.java:136)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.app.ActivityThread.main(ActivityThread.java:5017)
04-03 15:54:55.687: E/AndroidRuntime(1174): at java.lang.reflect.Method.invokeNative(Native Method)
04-03 15:54:55.687: E/AndroidRuntime(1174): at java.lang.reflect.Method.invoke(Method.java:515)
04-03 15:54:55.687: E/AndroidRuntime(1174): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
04-03 15:54:55.687: E/AndroidRuntime(1174): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
04-03 15:54:55.687: E/AndroidRuntime(1174): at dalvik.system.NativeStart.main(Native Method)
04-03 15:54:55.687: E/AndroidRuntime(1174): Caused by: java.lang.NullPointerException
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.view.ViewGroup.addViewInner(ViewGroup.java:3561)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.view.ViewGroup.addView(ViewGroup.java:3415)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.view.ViewGroup.addView(ViewGroup.java:3391)
04-03 15:54:55.687: E/AndroidRuntime(1174): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:309)
04-03 15:54:55.687: E/AndroidRuntime(1174): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:299)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.app.Activity.setContentView(Activity.java:1949)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.support.v7.app.ActionBarActivity.superSetContentView(ActionBarActivity.java:220 )
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.support.v7.app.ActionBarActivityDelegateICS.setContentView(ActionBarActivityDel egateICS.java:106)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.support.v7.app.ActionBarActivity.setContentView(ActionBarActivity.java:81)
04-03 15:54:55.687: E/AndroidRuntime(1174): at com.example.myfirstapp2.MainActivity.onCreate(MainActivity.java:20)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.app.Activity.performCreate(Activity.java:5231)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
04-03 15:54:55.687: E/AndroidRuntime(1174): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
04-03 15:54:55.687: E/AndroidRuntime(1174): ... 11 more
04-03 15:55:06.527: I/Process(1174): Sending signal. PID: 1174 SIG: 9
What must I do? When I run it on the emulator I get a message "Unfortunately MyFirstApp has stopped"
