public boolean onKeyDown(int keyCode, KeyEvent event) {// 如果是返回键,直接返回到桌面if(keyCode == KeyEvent.KEYCODE_BACK || keyCode == KeyEvent.KEYCODE_HOME){showExitGameAlert();}return super.onKeyDown(keyCode, event);
}
private void showExitGameAlert() {final AlertDialog dlg = new AlertDialog.Builder(this).create();dlg.show();Window window = dlg.getWindow();// *** 主要就是在这里实现这种效果的.// 设置窗口的内容页面,shrew_exit_dialog.xml文件中定义view内容
 window.setContentView(R.layout.shrew_exit_dialog);// 为确认按钮添加事件,执行退出应用操作ImageButton ok = (ImageButton) window.findViewById(R.id.btn_ok);ok.setOnClickListener(new View.OnClickListener() {public void onClick(View v) {exitApp(); // 退出应用...
  }});// 关闭alert对话框架ImageButton cancel = (ImageButton) window.findViewById(R.id.btn_cancel);cancel.setOnClickListener(new View.OnClickListener() {public void onClick(View v) {dlg.cancel();}});
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayoutxmlns:Android="http://schemas.android.com/apk/res/android"android:layout_height="wrap_content"android:layout_width="wrap_content"><!-- 退出游戏的背景图 --><ImageView android:id="@+id/exitGameBackground"android:layout_centerInParent="true"android:layout_height="wrap_content"android:layout_width="wrap_content"android:src="@drawable/bg_exit_game" /><!-- 确认按钮 --><ImageButton android:layout_alignBottom="@+id/exitGameBackground"android:layout_alignLeft="@+id/exitGameBackground"android:layout_marginBottom="30dp"android:layout_marginLeft="35dp"android:id="@+id/btn_ok"android:layout_height="wrap_content"android:layout_width="wrap_content"android:background="@drawable/btn_ok" /><!-- 取消按钮 --><ImageButton android:layout_alignBottom="@+id/exitGameBackground"android:layout_alignRight="@+id/exitGameBackground"android:layout_marginBottom="30dp"android:layout_marginRight="35dp"android:id="@+id/btn_cancel"android:layout_height="wrap_content"android:layout_width="wrap_content"android:background="@drawable/btn_cancel" />
</RelativeLayout>