双击退出程序

<pre name="code" class="java"> //再按一次退出程序,timeSpace = 0;    @Override    public boolean onKeyDown(int keyCode, KeyEvent event) {        Log.e("keyCode", keyCode + "");        if (keyCode == KeyEvent.KEYCODE_BACK) {            if (System.currentTimeMillis() - timeSpace > 2000) {                timeSpace = System.currentTimeMillis();                Toast.makeText(MainActivity.this, "再按一次退出程序", Toast.LENGTH_SHORT).show();            }            else {                setResult(1);//resultCode 结果码                finish();            }        }        return true;    }