APP дает ошибку и перестает работать на android

Question

Я проверил alert.class, чтобы найти ошибку, потому что в файле logcat была обнаружена ошибка при запуске действия alert.class, но я не могу найти никаких ошибок.
Вот код:

public class alert extends Activity 
{ 
    Button button1; 
    Button button2; 

public void onCreate(Bundle savedInstanceState) 
{ 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.alert); 
    button1 = (Button) findViewById(R.id.button1); 
    button2 = (Button) findViewById(R.id.button2); 

    button1.setOnClickListener(new OnClickListener() 
    { 
     public void onClick(View v1) 
     { 
     setContentView(R.layout.set); 
     Intent myIntent = new Intent(getApplicationContext(), set.class); 
     startActivity(myIntent); 

     } 
    }); 
    button2.setOnClickListener(new OnClickListener() 
    { 
     public void onClick(View v1) 
     { 
      setContentView(R.layout.set); 
      Intent myIntent = new Intent(getApplicationContext(), set.class); 
      startActivity(myIntent); 
     } 
    }); 
} 

}

это LogCat:

03-23 08:28:28.239: E/AndroidRuntime(463): FATAL EXCEPTION: main 
03-23 08:28:28.239: E/AndroidRuntime(463): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.indianic.demo.calendark/com.indianic.demo.calendark.alert}: java.lang.NullPointerException 
03-23 08:28:28.239: E/AndroidRuntime(463): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 
03-23 08:28:28.239: E/AndroidRuntime(463): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 
03-23 08:28:28.239: E/AndroidRuntime(463): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
03-23 08:28:28.239: E/AndroidRuntime(463): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 
03-23 08:28:28.239: E/AndroidRuntime(463): at android.os.Handler.dispatchMessage(Handler.java:99) 
03-23 08:28:28.239: E/AndroidRuntime(463): at android.os.Looper.loop(Looper.java:123) 
03-23 08:28:28.239: E/AndroidRuntime(463): at android.app.ActivityThread.main(ActivityThread.java:3683) 
03-23 08:28:28.239: E/AndroidRuntime(463): at java.lang.reflect.Method.invokeNative(Native Method) 
03-23 08:28:28.239: E/AndroidRuntime(463): at java.lang.reflect.Method.invoke(Method.java:507) 
03-23 08:28:28.239: E/AndroidRuntime(463): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
03-23 08:28:28.239: E/AndroidRuntime(463): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
03-23 08:28:28.239: E/AndroidRuntime(463): at dalvik.system.NativeStart.main(Native Method) 
03-23 08:28:28.239: E/AndroidRuntime(463): Caused by: java.lang.NullPointerException 
03-23 08:28:28.239: E/AndroidRuntime(463): at com.indianic.demo.calendark.alert.onCreate(alert.java:37) 
03-23 08:28:28.239: E/AndroidRuntime(463): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
03-23 08:28:28.239: E/AndroidRuntime(463): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 
03-23 08:28:28.239: E/AndroidRuntime(463): ... 11 more 

Answer 1

button1.setOnClickListener(new OnClickListener() 
{ 
    public void onClick(View v1) 
    { 
     // dont set layout here 
    Intent myIntent = new Intent(getApplicationContext(), set.class); 
    startActivity(myIntent); // after starting activity set.java it will create layout it self 

    } 
}); 
button2.setOnClickListener(new OnClickListener() 
{ 
    public void onClick(View v1) 
    { 

     Intent myIntent = new Intent(getApplicationContext(), set.class); 
     startActivity(myIntent); 
    } 
});