2020-07-29Android连点2次back键退出

方法1

private boolean isQuit =false;

@Override

public void onBackPressed() {

    if (!isQuit) {

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

        isQuit =true;

        //这段代码意思是,在两秒钟之后isQuit会变成false

        new Thread(()->{

            try {

                Thread.sleep(2000);

              }catch (InterruptedException e) {

                    e.printStackTrace();

              }finally {

                    isQuit =false;

              }

        }).start();

    }else {

        System.exit(0);

    }

}

方法2

private long firstTime =0;

@Override

public boolean onKeyDown(int keyCode, KeyEvent event) {

long secondTime = System.currentTimeMillis();

if (keyCode == KeyEvent.KEYCODE_BACK) {

if ( secondTime -firstTime <2000) {

System.exit(0);

}else {

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

firstTime = System.currentTimeMillis();

}

return true;

}

return super.onKeyDown(keyCode, event);

}