android 再按一次退出程序

    private long firstTime = 0;
    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_UP) {
            long secondTime = System.currentTimeMillis();
            if (secondTime - firstTime > 2000) {
                ToastUtils.Toast("再按一次退出程序");
                firstTime = secondTime;
                return true;
            } else {
                finish();
            }
        }
        return super.onKeyUp(keyCode, event);
    }