Detect which Hot keys is being pressed

问题:

How can I detect which key combination is being pressed?

For example I want to recognize Back and Menu button being pressed simultaneously or any key combination.

I would like to open my application on the basis on which key is being pressed.

回答1:

I did a simple research and found this solution and it may work. You can detect Menu key pressed by the following code.

public boolean onKey(View v, int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_MENU && event.getAction() == KeyEvent.ACTION_DOWN) {
            //Start a new thread here and run a while loop for listening to "back pressed" and trigger the event you want if the back button is pressed 
        } else {
            //stop the started thread above
            return false;
        }
    }

Hope this might help you. Thnks.

回答2:

As Daniel Lew said (Prompt user to save changes when Back button is pressed):

You're not quite on the right track; what you should be doing is overriding onKeyDown() and listening for the back key, then overriding the default behavior:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)  {
    if (keyCode == KeyEvent.KEYCODE_BACK && event.getRepeatCount() == 0) {
        // do something on back.
        return true;
    }

    return super.onKeyDown(keyCode, event);
}

If you're only supporting Android 2.0 and higher, they've added an onBackPressed() you can use instead:

@Override
public void onBackPressed() {
    // do something on back.
    return;
}

This answer is essentially ripped from this blog post: http://android-developers.blogspot.com/2009/12/back-and-other-hard-keys-three-stories.html