android 按两次返回键退出应用

Posted 2020-06-17

　　private long mExitTime;
    
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
　　　　　　　//设置回退
            if ((System.currentTimeMillis() - mExitTime) > 2000) {
                Toast.makeText(this, "再按一次退出程序", Toast.LENGTH_SHORT).show();
                mExitTime = System.currentTimeMillis();
            } else {
                this.finish();
            }
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }