java - 无法使用共享首选项保存游戏高分？

Question

这是我用来保存高分的游戏代码

SharedPreferences preferences = null;
SharedPreferences.Editor editor = null;


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

    //Highscore.easyHigh = 0;

    Highscore.easyHigh = preferences.getInt("EasyScore", 0);
    Highscore.mediumHigh = preferences.getInt("MediumScore", 0);
    Highscore.hardHigh = preferences.getInt("HardScore", 0);

现在我在玩家输掉游戏时设置这些值

editor = preferences.edit();
        if(level==1)
        editor.putInt("EasyScore", score);
        else if(level==2)
        editor.putInt("MediumScore", score);
        else if(level==3)
        editor.putInt("HardScore", score);
        editor.commit();

Highscore 我的类存储 public static int 是简单、中等还是困难？

我收到空指针异常，但为什么会发生这种情况？

Answer 1

您的首选项和编辑器值未初始化，请使用:

preferences = PreferencesManager.getDefaultSharedPreferenes(this);
editor = preferences.edit();