java - 如何将分数保存到 SharedPreferences 然后更新它？

Question

我有一个应用程序，它以 TextView 的形式显示 MainActivity 中明星的总收入。如果应用程序是第一次运行，我想做的是输入 0。然后，当我完成一个关卡并赢得一些星星(如 currentScore + 50 = newScore)时，它将被重定向到带有 newScore textView 的 MainActivity。

这是我的 MainActivity，其中 TextView 显示分数

public class MainActivity extends Activity {

  private static TextView txt_stars;

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

    public void updateStars() {
    SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putInt("Stars", 0);
    editor.commit();
    txt_stars = (TextView) findViewById(R.id.txtStars);
    sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
        //the key is "Stars" don't forget to type it as you created the Sp
    String stars = String.valueOf(sharedPreferences.getInt("Stars", 0));
    txt_stars.setText(stars);
}
}

对于我读取当前分数然后添加 50 然后更新的 Activity

public void onClick(DialogInterface dialog, int whichButton) {

     SharedPreferences sharedPreferences = 
     PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
     Integer newstars = sharedPreferences.getInt("Stars", 0);
     Integer totalStars = newstars + 50;
     SharedPreferences.Editor editor = sharedPreferences.edit();
     editor.putInt("Stars", totalStars);
     editor.commit();

  //please help me improve my code here

    Intent nextForm = new Intent(.MainActivity");
    startActivity(nextForm);

  }

SharedPreferences 也可以用于不同的 Activity 吗？就像我只是从 ActivityOne 中保存分数并可以在 ActivityTwo 中读取一样？

非常感谢!

Answer 1

嗯，你应该先阅读 the SharedPreferences documentation ，然后按照我的步骤使用 SharedPreferences

保存值

您的 UpdateStars() 方法应如下所示:

public class updateStars() {
txt_stars = (TextView) findViewById(R.id.txtStars);
sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
//the key is "Stars" don't forget to type it as you created the Sp
String stars = String.valueOf(sharedPreferences.getInt("Stars", 0));
txt_stars.setText(stars);
}

每次你想保持用户 Stars 时，你都必须使用 putInt() :

SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putInt("Stars", YOUR_INT_VALUE); //Here you save the stars of the user
editor.commit();