title: Unfortunately application has stopped android emulator genymotion
body: <p>I am new to android app development( from yesterday only i started to learn android ).</p>
  
  <p>I am getting message in AVD like - unfortunately has stopped ,please help me solve this error, I want learn more in android but sucked by this error.. plz..plz.. help me to sove this.</p>
  
  <p>my main.java is </p>
  
  <pre><code>package com.example.first;
  
  public class MainActivity extends Activity {
  
  
  int counter = 0 ;
  Button add,sub;
  TextView total;
  public void onCreate(Bundle savedInstanceState) {
  
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
  
  
      add = (Button) findViewById(R.id.bt_add);
      sub = (Button) findViewById(R.id.bt_sub);
      total = (TextView) findViewById(R.id.textView1);
  
  
      add.setOnClickListener(new View.OnClickListener() {
  
          public void onClick(View v) {
  
              counter++;
              total.setText("ur total is "+ counter);
  
          }
      });
  
  
  
  }
  
  @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;
      }
  }
  </code></pre>
  
  <p>}</p>
  
  <p>my main.xml is </p>
  
  <pre><code>&lt;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.first.MainActivity$PlaceholderFragment" &gt;
  
  &lt;TextView
      android:id="@+id/textView1"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:gravity="center"
      android:text="ur total is 0"
      android:textSize="40sp" /&gt;
  
      &lt;Button
          android:id="@+id/bt_add"
          android:layout_width="250dp"
          android:layout_height="40dp"
          android:layout_below="@+id/textView1"
          android:layout_centerHorizontal="true"
          android:layout_marginTop="20dp"
          android:text="add one" /&gt;
  
      &lt;Button
          android:id="@+id/bt_sub"
          android:layout_width="250dp"
          android:layout_height="40dp"
          android:layout_alignLeft="@+id/bt_add"
          android:layout_below="@+id/bt_add"
          android:layout_marginTop="19dp"
          android:text="sub one" /&gt;
  </code></pre>
  
  <p></p>
  
  <p>and the log is </p>
  
  <pre><code>        03-29 21:33:13.494: D/AndroidRuntime(1256): Shutting down VM
  03-29 21:33:13.494: W/dalvikvm(1256): threadid=1: thread exiting with uncaught exception (group=0xa4d6cb20)
  03-29 21:33:13.494: E/AndroidRuntime(1256): FATAL EXCEPTION: main
  03-29 21:33:13.494: E/AndroidRuntime(1256): Process: com.example.first, PID: 1256
  03-29 21:33:13.494: E/AndroidRuntime(1256): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.first/com.example.first.MainActivity}: java.lang.NullPointerException
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.os.Handler.dispatchMessage(Handler.java:102)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.os.Looper.loop(Looper.java:136)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.app.ActivityThread.main(ActivityThread.java:5017)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at java.lang.reflect.Method.invokeNative(Native Method)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at java.lang.reflect.Method.invoke(Method.java:515)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at dalvik.system.NativeStart.main(Native Method)
  03-29 21:33:13.494: E/AndroidRuntime(1256): Caused by: java.lang.NullPointerException
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at com.example.first.MainActivity.onCreate(MainActivity.java:39)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.app.Activity.performCreate(Activity.java:5231)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
  03-29 21:33:13.494: E/AndroidRuntime(1256):     ... 11 more
  03-29 21:34:01.629: D/dalvikvm(1310): Late-enabling CheckJNI
  03-29 21:34:01.673: D/AndroidRuntime(1310): Shutting down VM
  03-29 21:34:01.673: W/dalvikvm(1310): threadid=1: thread exiting with uncaught exception (group=0xa4d6cb20)
  03-29 21:34:01.673: E/AndroidRuntime(1310): FATAL EXCEPTION: main
  03-29 21:34:01.673: E/AndroidRuntime(1310): Process: com.example.first, PID: 1310
  03-29 21:34:01.673: E/AndroidRuntime(1310): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.first/com.example.first.MainActivity}: java.lang.NullPointerException
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.os.Handler.dispatchMessage(Handler.java:102)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.os.Looper.loop(Looper.java:136)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.app.ActivityThread.main(ActivityThread.java:5017)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at java.lang.reflect.Method.invokeNative(Native Method)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at java.lang.reflect.Method.invoke(Method.java:515)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at dalvik.system.NativeStart.main(Native Method)
  03-29 21:34:01.673: E/AndroidRuntime(1310): Caused by: java.lang.NullPointerException
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at com.example.first.MainActivity.onCreate(MainActivity.java:38)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.app.Activity.performCreate(Activity.java:5231)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
  03-29 21:34:01.673: E/AndroidRuntime(1310):     ... 11 more
  03-29 21:36:56.615: D/AndroidRuntime(1358): Shutting down VM
  03-29 21:36:56.615: W/dalvikvm(1358): threadid=1: thread exiting with uncaught exception (group=0xa4d6cb20)
  03-29 21:36:56.615: E/AndroidRuntime(1358): FATAL EXCEPTION: main
  03-29 21:36:56.615: E/AndroidRuntime(1358): Process: com.example.first, PID: 1358
  03-29 21:36:56.615: E/AndroidRuntime(1358): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.first/com.example.first.MainActivity}: java.lang.NullPointerException
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.os.Handler.dispatchMessage(Handler.java:102)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.os.Looper.loop(Looper.java:136)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.app.ActivityThread.main(ActivityThread.java:5017)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at java.lang.reflect.Method.invokeNative(Native Method)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at java.lang.reflect.Method.invoke(Method.java:515)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at dalvik.system.NativeStart.main(Native Method)
  03-29 21:36:56.615: E/AndroidRuntime(1358): Caused by: java.lang.NullPointerException
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at com.example.first.MainActivity.onCreate(MainActivity.java:38)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.app.Activity.performCreate(Activity.java:5231)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
  03-29 21:36:56.615: E/AndroidRuntime(1358):     ... 11 more
  03-29 21:48:16.663: D/AndroidRuntime(1395): Shutting down VM
  03-29 21:48:16.663: W/dalvikvm(1395): threadid=1: thread exiting with uncaught exception (group=0xa4d6cb20)
  03-29 21:48:16.663: E/AndroidRuntime(1395): FATAL EXCEPTION: main
  03-29 21:48:16.663: E/AndroidRuntime(1395): Process: com.example.first, PID: 1395
  03-29 21:48:16.663: E/AndroidRuntime(1395): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.first/com.example.first.MainActivity}: java.lang.NullPointerException
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.os.Handler.dispatchMessage(Handler.java:102)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.os.Looper.loop(Looper.java:136)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.app.ActivityThread.main(ActivityThread.java:5017)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at java.lang.reflect.Method.invokeNative(Native Method)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at java.lang.reflect.Method.invoke(Method.java:515)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at dalvik.system.NativeStart.main(Native Method)
  03-29 21:48:16.663: E/AndroidRuntime(1395): Caused by: java.lang.NullPointerException
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at com.example.first.MainActivity.onCreate(MainActivity.java:38)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.app.Activity.performCreate(Activity.java:5231)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
  03-29 21:48:16.663: E/AndroidRuntime(1395):     ... 11 more
  03-29 22:09:36.395: D/AndroidRuntime(1448): Shutting down VM
  03-29 22:09:36.395: W/dalvikvm(1448): threadid=1: thread exiting with uncaught exception (group=0xa4d6cb20)
  03-29 22:09:36.395: E/AndroidRuntime(1448): FATAL EXCEPTION: main
  03-29 22:09:36.395: E/AndroidRuntime(1448): Process: com.example.first, PID: 1448
  03-29 22:09:36.395: E/AndroidRuntime(1448): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.first/com.example.first.MainActivity}: java.lang.NullPointerException
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.app.ActivityThread.access$800(ActivityThread.java:135)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.os.Handler.dispatchMessage(Handler.java:102)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.os.Looper.loop(Looper.java:136)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.app.ActivityThread.main(ActivityThread.java:5017)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at java.lang.reflect.Method.invokeNative(Native Method)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at java.lang.reflect.Method.invoke(Method.java:515)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at dalvik.system.NativeStart.main(Native Method)
  03-29 22:09:36.395: E/AndroidRuntime(1448): Caused by: java.lang.NullPointerException
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at com.example.first.MainActivity.onCreate(MainActivity.java:38)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.app.Activity.performCreate(Activity.java:5231)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
  03-29 22:09:36.395: E/AndroidRuntime(1448):     ... 11 more
  </code></pre>
  
  <p>plz.. explain why am getting like this.. tell me the solution</p>