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;
    }