Development Example – Action Button

The default behavior of the action button is to navigate the user back to the system’s home screen. This behavior can be overwritten by an application if required. Since this changes the behavior that the user may expect it is not recommended to use this feature often.

Before capturing the action button you should disable the default behavior of navigating to the home screen:

@Override 
     protected void onCreate(Bundle savedInstanceState) { 
          // Disable the action button default behavior 
          mActionButtonImageView.setContentDescription("hf_no_ptt_home"); 
}

The action button functions as a normal key press and so can be handled in the standard Android way for any other key press. The action button’s key code is set to 500.

private static final int ActionBtnKeyCode = 500; 
     @Override public boolean onKeyDown(int keyCode, KeyEvent event) { 
          switch (keyCode) { 
               case ActionBtnKeyCode: 
                    // Action key is down - return true to stop default behavior 
                    return true; 
               }

               return super.onKeyDown(keyCode, event); 
     } 

     @Override 
     public boolean onKeyUp(int keyCode, KeyEvent event) { 
          switch (keyCode) { 
               case ActionBtnKeyCode: 
                    // Action key has been released - return true to stop default behavior 
                    return true; 
          } 

          return super.onKeyUp(keyCode, event); 
}

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