android 长按返回键处理

在PhoneWindowManager.java里interceptKeyBeforeDispatching加   

else if (keyCode == KeyEvent.KEYCODE_BACK) {

            if (down) {
                if (repeatCount == 0) {
                } else if (repeatCount == 1) {
                    if (!keyguardOn) {
                         launchBackLongPressAction();
                    return -1;
                    }
                }
            }
        }