activity中实现点连续点击两次返回键后程序退出(间隔1.5秒)

一般用于fragment布局的mainActivity中,也就是首页中.

private long etime = 0;@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {    if (keyCode == KeyEvent.KEYCODE_BACK) {        long stime = System.currentTimeMillis();        if (etime == 0 || stime - etime > 1500) {            Toast.makeText(this, "再按一次退出", Toast.LENGTH_SHORT).show();            etime = System.currentTimeMillis();            return true;        } else {            System.exit(0);        }    }    return super.onKeyDown(keyCode, event);}