恢复一个井字棋游戏在Android中关闭片段后， [英] Resuming a Tic-tac-toe game in Android after closing the fragment

问题描述

我通过创建一个测试项目学习Android开发。我的井字棋应用开始以按钮新游戏，上面写着一个主菜单的活动。之后点击新游戏，用含有井字棋游戏（在GridLayout）将启动一个片段的活动。用户可以玩游戏，但是当他们回到主菜单，游戏状态不会被保存。

I'm learning Android development by creating a test project: Tic-tac-toe. My Tic-tac-toe app starts with a Main Menu activity with a Button that says New Game. After clicking New Game, an activity with a fragment containing a Tic-Tac-Toe game (in a GridLayout) launches. The user can play the game, but when they go back to the Main Menu, the game state is not saved.

我要改变这一点，以便当用户返回到主菜单，就会看到一个新的按钮所谓的继续（除新游戏按钮）。一旦用户点击继续，本场比赛之前，他们被打仍在继续。如果点击新游戏按钮，新游戏会像前推出。

I want to change this so that when the user goes back to the Main Menu, they will see a new Button called "Continue" (in addition to the "New Game" Button). Once the user clicks "Continue", the game they were playing before continues. If the click the "New Game" button, a new game will be launched like before.

通过使用的onSaveInstanceState 方法和捆绑 savedInstanceState ，我能preserve的方向改变游戏状态（通过保存从底层井字游戏类中的数据）。下面我code说明我是如何做到这一点。我想这个时候再次做同样的事情 - 我看了一下，但我不太明白，以最好的方式开始。谁能告诉我正确的步骤？

By using the onSaveInstanceState method and a Bundle savedInstanceState, I was able to preserve the game state on orientation changes (by saving the data from the underlying TicTacToe class). My code below shows how I did that. I would like to do something similar this time again - I have read about it, but I don't quite understand the best way to start. Can anyone show me the right steps?

请注意，我做这种编程方式（即设计的XML文件以外的布局）！

Note that I'm doing this programmatically (i.e. designing the layout outside the xml files)!

我的的MainMenu 类：

public class MainMenu extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_menu);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    public void startGame(View view) {
        Intent intent = new Intent(this,MainGame.class);
        startActivity(intent);
    }

}

有相应的XML文件 activity_main_game ：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/new_game"
        android:onClick="startGame"

        />

</RelativeLayout>

现在我的 MainGame.class 是这样的：

public class MainGame extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_game);
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new BoardFragment()).commit();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main_game, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    public static class BoardFragment extends Fragment {

        public TicTacToe t = new TicTacToe();  //A class I wrote that launches a simple TicTacToe game

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

            if (savedInstanceState != null) {
                t = new TicTacToe(savedInstanceState.getInt("TicTacToeData"),
                );
            }

    //Graphics stuff here: variable rootView which contains the TicTacToe grid is defined
    //and onClickListeners are added to the ImageViews in the GridLayout which makes corresponding
    //changes to t.

            return rootView;
        }

        @Override
        public void onSaveInstanceState(Bundle savedInstanceState) {
            savedInstanceState.putInt("TicTacToeData", t.getGameData());
        }

    }
}

感谢您的帮助。

Thanks for any help.

推荐答案

另一种解决方案是重新设计你的应用程序只有一个活动（或 ActionBarActivity ）的子类和多个片段子类，每个屏幕要显示。你可以保持一个参考两个片段在活动。这会隐保留其中显示了游戏板的片段的状态。

Another solution is to redesign your app to have only a single Activity (or ActionBarActivity) subclass and multiple Fragment subclasses for each screen you want to show. You can keep a reference to both fragments in your Activity. This will implicitly retain the state of the fragment which displays the game board.

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