title: One button two listeners in java
body: <p>im trying to setup two listeners for one button. Here is my code:
  This is the main code</p>
  
  <pre><code>            public class LoggingEventsActivity extends Activity  implements OnClickListener {
                  /** Called when the activity is first created. */
                  @Override
                  public void onCreate(Bundle savedInstanceState) {
                      super.onCreate(savedInstanceState);
                      setContentView(R.layout.main);
  
                      temp obj = new temp(R.id.button1,this);
  
                      View continueButton = findViewById(R.id.button1);
                      continueButton.setOnClickListener(this);
                  }
  
                  @Override
                  public void onClick(View v) {
                      // TODO Auto-generated method stub
  
                      final TextView t=(TextView)findViewById(R.id.editText1);
                      t.setText("hello world");
  
                  }
              }
  </code></pre>
  
  <p>This is a class which i create an object in the main code :</p>
  
  <pre><code>            public class temp extends Activity implements OnClickListener{
  
  
                  public temp(int id, LoggingEventsActivity  ref){
                      try{
  
                      View continueButton = findViewById(id);
                      continueButton.setOnClickListener(ref);
                      }
                      catch (Exception e){
                          e.printStackTrace();
                      }
                  }
  
                  @Override
                  public void onClick(View v) {
                      // TODO Auto-generated method stub
                      final TextView t=(TextView)findViewById(R.id.editText1);
                      t.append("extra");
                  }  
  
              }
  </code></pre>
  
  <p>I keep getting a null pointer exception here is the logcat dump:</p>
  
  <pre><code>            11-15 11:08:29.589: W/System.err(24268): java.lang.NullPointerException
              11-15 11:08:29.605: W/System.err(24268):    at android.app.Activity.setContentView(Activity.java:1835)
              11-15 11:08:29.616: W/System.err(24268):    at events.log.temp.&lt;init&gt;(temp.java:15)
              11-15 11:08:29.635: W/System.err(24268):    at events.log.LoggingEventsActivity.onCreate(LoggingEventsActivity.java:17)
              11-15 11:08:29.655: W/System.err(24268):    at android.app.Activity.performCreate(Activity.java:4465)
              11-15 11:08:29.664: W/System.err(24268):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
              11-15 11:08:29.675: W/System.err(24268):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
              11-15 11:08:29.685: W/System.err(24268):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
              11-15 11:08:29.696: W/System.err(24268):    at android.app.ActivityThread.access$600(ActivityThread.java:122)
              11-15 11:08:29.704: W/System.err(24268):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
              11-15 11:08:29.715: W/System.err(24268):    at android.os.Handler.dispatchMessage(Handler.java:99)
              11-15 11:08:29.725: W/System.err(24268):    at android.os.Looper.loop(Looper.java:137)
              11-15 11:08:29.735: W/System.err(24268):    at android.app.ActivityThread.main(ActivityThread.java:4340)
              11-15 11:08:29.744: W/System.err(24268):    at java.lang.reflect.Method.invokeNative(Native Method)
              11-15 11:08:29.766: W/System.err(24268):    at java.lang.reflect.Method.invoke(Method.java:511)
              11-15 11:08:29.784: W/System.err(24268):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
              11-15 11:08:29.784: W/System.err(24268):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
              11-15 11:08:29.795: W/System.err(24268):    at dalvik.system.NativeStart.main(Native Method)
              11-15 11:08:37.355: D/gralloc_goldfish(24268): Emulator without GPU emulation detected.
              11-15 11:09:34.365: D/dalvikvm(24268): Debugger has detached; object registry had 441 entries
              11-15 11:14:20.436: W/System.err(24548): java.lang.NullPointerException
              11-15 11:14:20.445: W/System.err(24548):    at android.app.Activity.findViewById(Activity.java:1794)
              11-15 11:14:20.445: W/System.err(24548):    at events.log.temp.&lt;init&gt;(temp.java:15)
              11-15 11:14:20.445: W/System.err(24548):    at events.log.LoggingEventsActivity.onCreate(LoggingEventsActivity.java:17)
              11-15 11:14:20.455: W/System.err(24548):    at android.app.Activity.performCreate(Activity.java:4465)
              11-15 11:14:20.455: W/System.err(24548):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
              11-15 11:14:20.455: W/System.err(24548):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1919)
              11-15 11:14:20.455: W/System.err(24548):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1980)
              11-15 11:14:20.455: W/System.err(24548):    at android.app.ActivityThread.access$600(ActivityThread.java:122)
              11-15 11:14:20.455: W/System.err(24548):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1146)
              11-15 11:14:20.455: W/System.err(24548):    at android.os.Handler.dispatchMessage(Handler.java:99)
              11-15 11:14:20.465: W/System.err(24548):    at android.os.Looper.loop(Looper.java:137)
              11-15 11:14:20.465: W/System.err(24548):    at android.app.ActivityThread.main(ActivityThread.java:4340)
              11-15 11:14:20.465: W/System.err(24548):    at java.lang.reflect.Method.invokeNative(Native Method)
              11-15 11:14:20.475: W/System.err(24548):    at java.lang.reflect.Method.invoke(Method.java:511)
              11-15 11:14:20.475: W/System.err(24548):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
              11-15 11:14:20.475: W/System.err(24548):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
              11-15 11:14:20.475: W/System.err(24548):    at dalvik.system.NativeStart.main(Native Method)
  </code></pre>