Android detect phone lock event

I want to be able to detect the phone lock event. When my app is running, if I press the red button (call end button/power button), the phone gets locked and the screen goes blank. I want to be able to detect this event, is it possible?

Alternatively you could do this:

@Override
protected void onPause()
{
    super.onPause();

    // If the screen is off then the device has been locked
    PowerManager powerManager = (PowerManager) getSystemService(POWER_SERVICE);
    boolean isScreenOn;
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT_WATCH) {
        isScreenOn = powerManager.isInteractive();
    } else {
        isScreenOn = powerManager.isScreenOn();
    }

    if (!isScreenOn) {

        // The screen has been locked 
        // do stuff...
    }
}

Have a Broadcast Receiver

android.intent.action.SCREEN_ON

and

android.intent.action.SCREEN_OFF

Related: Read CommonsWare's Answer Here.