Java 跨多个活动共享数据引用

首先，我很抱歉，如果这是一个重复，我搜索，并没有找到答案

我试图在多个活动中保持分数。用户启动MainActivity，选择要回答的问题并重定向到该活动。用户获得正确答案将获得一分，并返回Main活动以选择新问题

它可以正确地为问题打分，但不会在问题之间保存分数

主要活动

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


    SharedPreferences settings = getSharedPreferences("userScore", Context.MODE_PRIVATE);

    SharedPreferences.Editor editor = settings.edit();
    editor.putInt("score", userPoints);
    editor.commit();


};

Q1（每个问题的逻辑都相同。只需单击按钮即可运行）

我对这个很陌生，我知道我错过了一些东西，我只是不知道它是什么。非常感谢您的帮助

***编辑****

这是调用分数的按钮，它仍然只计算6分中的1分

private int userPoints;
TextView pointsAwarded;
ImageButton home;
Button check;
int points;
SharedPreferences settings;    

check.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                settings = getSharedPreferences("userScore", Context.MODE_PRIVATE);
                points = settings.getInt("score", userPoints);

                pointsAwarded.setText(String.valueOf(points));
            }
        });

```

```

---

在此之后，您应该保存用户点。也许你忘了。

代码实际上有一些地方出了问题。首先，您将在

main活动中保存
分数
，或者读取分数。您正在
submitAnswer
中读取
分数
，或者编辑分数

在处理
SharedReferences
时，我通常比较悲观，因此我会检查该键是否已设置为
contains（）

现在，在问题活动中，您可以从
SharedReferences
读取当前点，并更新值并保存回
SharedReferences

public void submitAnswer (View view) {
    if (correctAnswer.isChecked()) {
        SharedPreferences settings = getSharedPreferences("userScore", Context.MODE_PRIVATE);
        if(settings.contains("score"){
            int points = settings.getInt("score", 0);
            points++;

            SharedPreferences.Editor editor = settings.edit();
            editor.putInt("score", points);
            editor.commit();
            Toast.makeText(this, "Answer saved : points = " + points, Toast.LENGTH_SHORT).show();
        }
        else{
            Log.e(TAG, "No score yet!");
        }
    } 
    else{
            Toast.makeText(this, "Wrong Answer", Toast.LENGTH_SHORT).show();
    }

    // There is no need to start the MainActivity through a new Intent just call finish();
    finish();
    //... and you return to the Activity that is at the top of the stack.

    //Intent intent = new Intent(Q1.this, MainActivity.class);
    //startActivity(intent);
}

您必须将当前用户点添加到保存的点中，然后在添加后保存：

private SharedPreferences settings;
private int userPoints;
private int points;
public void submitAnswer (View view) {

if (correctAnswer.isChecked()) {
    userPoints = userPoints + 1;
} else {
    userPoints = userPoints;
}

settings = getSharedPreferences("userScore", Context.MODE_PRIVATE);
points = settings.getInt("score", userPoints);

userPoints = userPoints + points ; // addition of current userpoints with saved points 

  // Now save this points 
  SharedPreferences.Editor editor = settings.edit();
  editor.putInt("score", userPoints );
  editor.commit();

Toast.makeText(this, "Answer saved", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(Q1.this, MainActivity.class);
startActivity(intent);
}

在Q1中，In think是您想要更新值的地方，不是吗？您当前在Main中执行
put
，而在Q1活动中执行的
get
似乎应该被反转。@Deb:：请注意，通过使用
finish（）
方法，您将返回到
Main活动
活动，但不会触发
onCreate（）
方法。相反，返回点将是
onResume（）
方法。请看一下Android活动生命周期@Deb：：看一下对onCreate（）方法的更改。这将在第一次初始化分数。我已经测试了这段代码，对我来说它工作正常。@Deb：如果它解决了您的问题，请将此答案标记为已接受的答案以结束问题；）非常感谢你。我知道我忘了什么。
private int points;

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

    SharedPreferences settings = getSharedPreferences("userScore", Context.MODE_PRIVATE);
    if(settings.contains("score"){
        points = settings.getInt("score", userPoints);
    }
    else{
        Log.e(TAG, "No score yet!");

        SharedPreferences.Editor editor = settings.edit();
        editor.putInt("score", 0);
        editor.commit();
    }
}

public void submitAnswer (View view) {
    if (correctAnswer.isChecked()) {
        SharedPreferences settings = getSharedPreferences("userScore", Context.MODE_PRIVATE);
        if(settings.contains("score"){
            int points = settings.getInt("score", 0);
            points++;

            SharedPreferences.Editor editor = settings.edit();
            editor.putInt("score", points);
            editor.commit();
            Toast.makeText(this, "Answer saved : points = " + points, Toast.LENGTH_SHORT).show();
        }
        else{
            Log.e(TAG, "No score yet!");
        }
    } 
    else{
            Toast.makeText(this, "Wrong Answer", Toast.LENGTH_SHORT).show();
    }

    // There is no need to start the MainActivity through a new Intent just call finish();
    finish();
    //... and you return to the Activity that is at the top of the stack.

    //Intent intent = new Intent(Q1.this, MainActivity.class);
    //startActivity(intent);
}

private SharedPreferences settings;
private int userPoints;
private int points;
public void submitAnswer (View view) {

if (correctAnswer.isChecked()) {
    userPoints = userPoints + 1;
} else {
    userPoints = userPoints;
}

settings = getSharedPreferences("userScore", Context.MODE_PRIVATE);
points = settings.getInt("score", userPoints);

userPoints = userPoints + points ; // addition of current userpoints with saved points 

  // Now save this points 
  SharedPreferences.Editor editor = settings.edit();
  editor.putInt("score", userPoints );
  editor.commit();

Toast.makeText(this, "Answer saved", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(Q1.this, MainActivity.class);
startActivity(intent);
}