android - 如何创建乐谱？

Question

我正在做一个问答应用程序，我想在每次人们标记正确答案时递增一个整数。当我处理多个 Activity (每个问题一个 Activity )时，我将 Extra 传递给每个 Activity ，当我回答 1º 问题时游戏将关闭，我想知道如何解决这个问题。代码如下:`

@Override
public class QuestionOneActivity extends AppCompatActivity {

    int score = 0;
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_question_one);

        Button btn = (Button)findViewById(R.id.button);
                    final RadioButton rd1 = (RadioButton)findViewById(R.id.radioButton);
                    final RadioButton rd2 = (RadioButton)findViewById(R.id.radioButton2);
                    final RadioButton rd3 = (RadioButton)findViewById(R.id.radioButton3);
                    final RadioButton rd4 = (RadioButton)findViewById(R.id.radioButton4);
                    final RadioButton rd5 = (RadioButton)findViewById(R.id.radioButton5);

                    btn.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            if(rd1.isChecked()){
                                Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                                intent.putExtra("score", score);
                                startActivity(intent);
                            }
                            if(rd2.isChecked()){
                                Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                                intent.putExtra("score", score);
                                startActivity(intent);
                            }
                            if(rd3.isChecked()){
                                ++score;
                                Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                                intent.putExtra("score", score);
                    startActivity(intent);
                }
                if(rd4.isChecked()){
                    Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                    intent.putExtra("score", score);
                    startActivity(intent);
                }
                if(rd5.isChecked()){
                    Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                    intent.putExtra("score", score);
                    startActivity(intent);
                }
            }

        });


    }
}

和问题二 Activity :

@Override
public class QuestionTwoActivity extends AppCompatActivity {

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_question_two);

        Intent intent = getIntent();
        int score = intent.getIntExtra("score", 0);


        Button btn2 = (Button)findViewById(R.id.button2);
        final RadioButton rd6 = (RadioButton)findViewById(R.id.radioButton6);
        final RadioButton rd7 = (RadioButton)findViewById(R.id.radioButton7);
        final RadioButton rd8 = (RadioButton)findViewById(R.id.radioButton8);
        final RadioButton rd9 = (RadioButton)findViewById(R.id.radioButton9);
        final RadioButton rd10 = (RadioButton)findViewById(R.id.radioButton10);

        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(rd6.isChecked()){
                    Intent intent = new Intent(getApplicationContext(),QuestionThreeActivity.class);
                    intent.putExtra("score", score);
                    startActivity(intent);
                }
                if(rd7.isChecked()){
                    Intent intent = new Intent(getApplicationContext(),QuestionThreeActivity.class);
                    intent.putExtra("score", score);
                    startActivity(intent);
                }
                if(rd8.isChecked()){
                    Intent intent = new Intent(getApplicationContext(),QuestionThreeActivity.class);
                    intent.putExtra("score", score);
                    startActivity(intent);
                }
                if(rd9.isChecked()){
                    Intent intent = new Intent(getApplicationContext(),QuestionThreeActivity.class);
                    intent.putExtra("score", score);
                    startActivity(intent);
                }
                if(rd10.isChecked()){
                    Intent intent = new Intent(getApplicationContext(),QuestionThreeActivity.class);
                    intent.putExtra("score", score);
                    startActivity(intent);
                 }
            }

        });


    }
}

`问题是:它在分数变量的第二个问题 Activity 中显示错误消息。它说我必须使用最终声明，但我不能使用最终声明，因为如果有人正确回答了问题，我必须增加分数。我该如何解决这个问题？

Answer 1

我回答过类似的问题How to save score to SharedPreferences then update it .

这是怎么做的:

这就是您创建 SharedPreferences

的方式

SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putInt("score", YOUR_INT_VALUE); 
editor.commit();

然后在需要获取该值的地方，您只需这样做:

sharedPreferences.getInt("score", 0)

希望你已经清楚了。

示例

您的 QuestionOneActivity 应该如下所示:

public class QuestionOneActivity extends AppCompatActivity {
SharedPreferences sharedPreferences;
SharedPreferences.Editor editor;
int score = 0;
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_question_one);
    //If you want you can initialite the score to 0 doing this (IT'S NOT NECESSARY)
    SharedPreferences = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
    editor = sharedPreferences.edit();
    editor.putInt("score", 0);
    editor.commit();
    Button btn = (Button)findViewById(R.id.button);
    final RadioButton rd1 = (RadioButton)findViewById(R.id.radioButton);
    final RadioButton rd2 = (RadioButton)findViewById(R.id.radioButton2);
    final RadioButton rd3 = (RadioButton)findViewById(R.id.radioButton3);
    final RadioButton rd4 = (RadioButton)findViewById(R.id.radioButton4);
    final RadioButton rd5 = (RadioButton)findViewById(R.id.radioButton5);

    btn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if(rd1.isChecked()){
                Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                startActivity(intent);
            }
            if(rd2.isChecked()){
                Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                startActivity(intent);
            }
            //Everytime you want to ++ your score, now you'll do this
            if(rd3.isChecked()){
                editor = sharedPreferences.edit();
                editor.putInt("score", (sharedPreferences.getInt("score", 0))+1);
                editor.commit();
                Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                startActivity(intent);
            }
            if(rd4.isChecked()){
                Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                startActivity(intent);
            }
            if(rd5.isChecked()){
                Intent intent = new Intent(getApplicationContext(),QuestionTwoActivity.class);
                startActivity(intent);
            }
        }
    });
}

然后而不是做

int score = intent.getIntExtra("score", 0);

你可以这样做:

int score = sharedPreferences.getInt("score", 0);

注意:我不确定这条线是否有效

editor = sharedPreferences.edit();
editor.putInt("score", (sharedPreferences.getInt("score", 0))+1);
editor.commit();

如果没有，只需将 SharedPreferences 值保存到 int 中，然后执行++