Android 实现“再按一次退出程序”

From：http://blog.csdn.net/ldj299/article/details/7574365

 

个人觉得当用户按下后退键时，出现"再按一次退出"的提示防止误操作比弹出一个对话框是会更人性化的。话不多说上代码：

第一种：重写onKeyDown来监听：

    long waitTime = 2000;

    long touchTime = 0;

    

    @Override

    public boolean onKeyDown(int keyCode, KeyEvent event) {

        if(event.getAction() == KeyEvent.ACTION_DOWN && KeyEvent.KEYCODE_BACK == keyCode) {

            long currentTime = System.currentTimeMillis();

            if((currentTime-touchTime)>=waitTime) {

                Toast.makeText(this, "再按一次退出", Toast.LENGTH_SHORT).show();

                touchTime = currentTime;

            }else {

                finish();

            }

            return true;

        }

        return super.onKeyDown(keyCode, event);

    }

 

第二种是重写onBackPressed方法直接监听返回键：

　　@Override

    public void onBackPressed() {

//        super.onBackPressed();



        long currentTime = System.currentTimeMillis();

        if((currentTime - touchTime) >= waitTime) {

            Toast.makeText(this, "再按一次退出", Toast.LENGTH_SHORT).show();

            touchTime = currentTime;

        }else {

            finish();

        }

    }