Which method is called when I press back key on my phone?

I have an app that has a lot of activities, all created with ONACTIVITYRESULT.

Which method is called when I press back key?

I need to know it because I have to开发者_运维问答 override/implement code on it.

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The method that is called for is: onKeyDown of your current Activity.

You can use this to target all Android versions:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)  {
      if (keyCode == KeyEvent.KEYCODE_BACK) {
          return true;
      }

   return super.onKeyDown(keyCode, event);
}

If you're targeting newer Android devices, the API for Android 2.0 and above has made things a little easier:

@Override
public void onBackPressed() {
    return;
}

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You could try this. I have this code on the page after checking for the licence. If my user presses back, I do not want them to go onto the licence check page again so I just quit the app. You don't have to quit the app, you can call whatever you want in here...

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
    // Quit if back is pressed     
    if (keyCode == KeyEvent.KEYCODE_BACK)
    {
        moveTaskToBack(true);
        return true;
    }
    return super.onKeyDown(keyCode, event);
}