存储具有共享首选项的数据

Question

在过去的3天里，我从字面上花了6-8h/天来搜索，阅读和执行各种有关共享偏好的示例，而没有任何成功。我走到了一个终点...非常令人沮丧！我的问题如下：

- 客观：我目前正在进行一个非常基本的数学游戏，在该游戏中将为玩家提供一个（随机）方程式，彼此乘以两个数字。然后，播放器将通过简单地按三个选项按钮之一（包括正确的答案）来给出答案。为每个正确答案添加分数。

- 问题：现在，我想为游戏提供高分来存储最高分数。我如何使用共享的首选项或任何其他工作方法来存储数据。

"得分："（@ id/textscore）是我的textView，其中包含分数（testactivity.java）。"最高分数"（@ id/texttopscores）是我的文本视图，我想存储高分（HighScoreactivity.java）。

- 应用程序的结构：

My app looks like this:
(a) MainActivity - main page with a start button leading the player to the Menu (= MenuActivity)
(b) MenuActivity - here the player have 3 buttons options which includes:
       Play Button --> leading to the TESTActivity
       High Score button -->> leading to the HighScoreActivity
       Help button -->> leading to the HelpActivity

。

activity_test.xml

 <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/activity_test"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        tools:context="com.example.android.laboration2.TESTActivity">
        <TextView
            android:id="@+id/textOperator"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/textPartA"
            android:layout_centerHorizontal="true"
            android:text="x"
            android:textSize="55sp" />
        <TextView
            android:text="="
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@+id/textOperator"
            android:layout_alignLeft="@+id/textOperator"
            android:layout_alignStart="@+id/textOperator"
            android:layout_marginTop="70dp"
            android:id="@+id/textView"
            android:textSize="70sp" />
        <TextView
            android:id="@+id/textPartA"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignEnd="@+id/buttonChoice1"
            android:layout_alignParentTop="true"
            android:layout_alignRight="@+id/buttonChoice1"
            android:layout_marginTop="36dp"
            android:text="2"
            android:textSize="60sp" />
        <TextView
            android:id="@+id/textPartB"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="2"
            android:textSize="60sp"
            android:layout_alignTop="@+id/textOperator"
            android:layout_alignLeft="@+id/buttonChoice3"
            android:layout_alignStart="@+id/buttonChoice3" />
        <Button
            android:id="@+id/buttonChoice2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignTop="@+id/buttonChoice1"
            android:layout_centerHorizontal="true"
            android:text="4"
            android:textSize="30sp" />
        <Button
            android:id="@+id/buttonChoice3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignBottom="@+id/buttonChoice2"
            android:layout_alignParentEnd="true"
            android:layout_alignParentRight="true"
            android:text="6"
            android:textSize="30sp" />
        <Button
            android:id="@+id/buttonChoice1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true"
            android:layout_below="@+id/textView"
            android:layout_marginTop="70dp"
            android:text="2"
            android:textSize="30sp" />
        <TextView
            android:id="@+id/textScore"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Score:"
            android:textSize="24sp"
            android:layout_alignParentBottom="true"
            android:layout_toLeftOf="@+id/buttonChoice2"
            android:layout_toStartOf="@+id/buttonChoice2"
            android:layout_marginRight="30dp"
            android:layout_marginEnd="30dp"
            android:layout_marginBottom="14dp" />
        <TextView
            android:id="@+id/textLevel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Level:"
            android:textSize="24sp"
            android:layout_alignBaseline="@+id/textScore"
            android:layout_alignBottom="@+id/textScore"
            android:layout_alignRight="@+id/textPartB"
            android:layout_alignEnd="@+id/textPartB" />
    </RelativeLayout>

testActivity.java

package com.example.android.laboration2;
import android.content.Context;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import java.util.Random;
public class TESTActivity extends AppCompatActivity implements View.OnClickListener {
    Button buttonObjectChoice1;
    Button buttonObjectChoice2;
    Button buttonObjectChoice3;
    TextView textObjectPartA;
    TextView textObjectPartB;
    TextView textObjectScore;
    TextView textObjectLevel;
    TextView textObjectHighScoresScores;
    int correctAnswer;
    int currentScore = 0;
    int currentLevel = 1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_test);
        textObjectPartA = (TextView) findViewById(R.id.textPartA);
        textObjectPartB = (TextView) findViewById(R.id.textPartB);
        textObjectHighScoresScores = (TextView) findViewById(R.id.textHighScoresScores);
        textObjectScore = (TextView) findViewById(R.id.textScore);
        textObjectLevel = (TextView) findViewById(R.id.textLevel);
        buttonObjectChoice1 = (Button) findViewById(R.id.buttonChoice1);
        buttonObjectChoice2 = (Button) findViewById(R.id.buttonChoice2);
        buttonObjectChoice3 = (Button) findViewById(R.id.buttonChoice3);
        buttonObjectChoice1.setOnClickListener(this);
        buttonObjectChoice2.setOnClickListener(this);
        buttonObjectChoice3.setOnClickListener(this);
        //Storing the score
        String highScore = textObjectHighScoresScores.getText().toString();
        int newHighScore = currentScore;
        SharedPreferences prefs = this.getSharedPreferences("StoringScore", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = prefs.edit();
        editor.putInt(highScore, newHighScore);
        editor.apply();
        setQuestion();
    }//onCreate ends here
    @Override
    public void onClick(View view) {
        //Declaring a new int which will be used in all the cases
        int answerGiven = 0;
        switch (view.getId()) {
            //Initializes a new int with a value for buttonObjectChoice1,2,3
            case R.id.buttonChoice1:
                answerGiven = Integer.parseInt("" + buttonObjectChoice1.getText());
                break;
            case R.id.buttonChoice2:
                answerGiven = Integer.parseInt("" + buttonObjectChoice2.getText());
                break;
            case R.id.buttonChoice3:
                answerGiven = Integer.parseInt("" + buttonObjectChoice3.getText());
                break;
        }//switch ends here
        updateScoreAndLevel(answerGiven);
        setQuestion();
        
    }//onClick ends here
    void setQuestion() {
        //Generates the parts of the question
        int numberRange = currentLevel * 3;
        Random randInt = new Random();
        int partA = randInt.nextInt(numberRange);
        partA++;//To avoid a zero value
        int partB = randInt.nextInt(numberRange);
        partB++;//To avoid a zero value
        correctAnswer = partA * partB;
        int wrongAnswer1 = correctAnswer - 2;
        int wrongAnswer2 = correctAnswer + 2;
        textObjectPartA.setText("" + partA);
        textObjectPartB.setText("" + partB);
        //Gives a number between 0 and 2 for the multi choice buttons
        int buttonLayout = randInt.nextInt(3);
        switch (buttonLayout) {
            case 0:
                buttonObjectChoice1.setText("" + correctAnswer);
                buttonObjectChoice2.setText("" + wrongAnswer1);
                buttonObjectChoice3.setText("" + wrongAnswer2);
                break;
            case 1:
                buttonObjectChoice2.setText("" + correctAnswer);
                buttonObjectChoice3.setText("" + wrongAnswer1);
                buttonObjectChoice1.setText("" + wrongAnswer2);
                break;
            case 2:
                buttonObjectChoice3.setText("" + correctAnswer);
                buttonObjectChoice1.setText("" + wrongAnswer1);
                buttonObjectChoice2.setText("" + wrongAnswer2);
                break;
        }//switch ends here
    }//setQuestion ends here
    //Updates the Score & Level for the player
    void updateScoreAndLevel(int answerGiven){
        if(isCorrect(answerGiven)){
            for(int i = 1; i <= currentLevel; i++){
                currentScore = currentScore + i;
            }
            currentLevel++;
        }else{
            currentScore = 0;
            currentLevel = 1;
        }
        //Updates the Score & Level TextViews
        textObjectScore.setText("Score: " + currentScore);
        textObjectLevel.setText("Level: " + currentLevel);
    }//updateScoreAndLevel ends here
    //Sends a toast message to the player - if right = Correct!, if wrong = Wrong! :(.
    boolean isCorrect(int answerGiven){
        boolean correctTrueOrFalse;
        if(answerGiven == correctAnswer){
            Toast.makeText(getApplicationContext(), "Correct!", Toast.LENGTH_LONG).show();
            correctTrueOrFalse=true;
        }else{
            Toast.makeText(getApplicationContext(), "Wrong! :(", Toast.LENGTH_LONG).show();
            correctTrueOrFalse=false;
        }
        return correctTrueOrFalse;
    }//isCorrect ends here
}//TESTActivity ends here

activity_high_score.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_high_score"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.android.laboration2.HighScoreActivity">
    <TextView
        android:text="@string/high_scores"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="62dp"
        android:id="@+id/textHighScore"
        android:textSize="30sp"/>
    <TextView
        android:text="@string/top_scores"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textTopScores"
        android:textSize="16sp"
        android:layout_below="@+id/textHighScore"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="86dp" />
</RelativeLayout>

highscoreactivity.java

package com.example.android.laboration2;
import android.content.Context;
import android.content.SharedPreferences;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class HighScoreActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_high_score);
        //getting preferences
        SharedPreferences prefs = this.getSharedPreferences("StoringScore", Context.MODE_PRIVATE);
        int newHighscore = prefs.getInt(highScore, null); //0 is the default value
        
    }//onCreate ends here
}//HighScoreActivity ends here

Answer 1

实际上是主要问题。

 //Storing the score
    String highScore = textObjectHighScoresScores.getText().toString();
    int newHighScore = currentScore;
    SharedPreferences prefs = this.getSharedPreferences("StoringScore", Context.MODE_PRIVATE);
    SharedPreferences.Editor editor = prefs.edit();
    editor.putInt(highScore, newHighScore);
    editor.apply();

editor.putInt(key,value)您使用的是高分作为钥匙，这将是更改，但是可以通过相同的键获得共享的偏好。

您应该像这样存储

SharedPreferences prefs = this.getSharedPreferences("StoringScore", Context.MODE_PRIVATE);
SharedPreferences.Editor editor = prefs.edit();
editor.putString("myKey", score);
editor.apply();

获得得分 ->

SharedPreferences prefs = this.getSharedPreferences("StoringScore", Context.MODE_PRIVATE);
int newHighscore = prefs.getInt("myKey", 0);

主要点是键应该相同

Answer 2

//I hope this will help you
public class TESTActivity extends AppCompatActivity implements View.OnClickListener{
Button buttonObjectChoice1;
Button buttonObjectChoice2;
Button buttonObjectChoice3;
TextView textObjectPartA;
TextView textObjectPartB;
TextView textObjectScore;
TextView textObjectLevel;
TextView textObjectHighScoresScores;
int correctAnswer;
int currentScore = 0;
int currentLevel = 1;

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

    textObjectPartA = (TextView) findViewById(R.id.textPartA);
    textObjectPartB = (TextView) findViewById(R.id.textPartB);
    //textObjectHighScoresScores = (TextView) findViewById(R.id.textScore);
    textObjectScore = (TextView) findViewById(R.id.textScore);
    textObjectLevel = (TextView) findViewById(R.id.textLevel);
    buttonObjectChoice1 = (Button) findViewById(R.id.buttonChoice1);
    buttonObjectChoice2 = (Button) findViewById(R.id.buttonChoice2);
    buttonObjectChoice3 = (Button) findViewById(R.id.buttonChoice3);
    buttonObjectChoice1.setOnClickListener(this);
    buttonObjectChoice2.setOnClickListener(this);
    buttonObjectChoice3.setOnClickListener(this);
    setQuestion();
}//onCreate ends here

@Override
public void onClick(View view) {
    //Declaring a new int which will be used in all the cases
    int answerGiven = 0;
    switch (view.getId()) {
        //Initializes a new int with a value for buttonObjectChoice1,2,3
        case R.id.buttonChoice1:
            answerGiven = Integer.parseInt("" + buttonObjectChoice1.getText());
            break;
        case R.id.buttonChoice2:
            answerGiven = Integer.parseInt("" + buttonObjectChoice2.getText());
            break;
        case R.id.buttonChoice3:
            answerGiven = Integer.parseInt("" + buttonObjectChoice3.getText());
            break;
    }//switch ends here
    updateScoreAndLevel(answerGiven);
    setQuestion();
}//onClick ends here

void setQuestion() {
    //Generates the parts of the question
    int numberRange = currentLevel * 3;
    Random randInt = new Random();
    int partA = randInt.nextInt(numberRange);
    partA++;//To avoid a zero value
    int partB = randInt.nextInt(numberRange);
    partB++;//To avoid a zero value
    correctAnswer = partA * partB;
    int wrongAnswer1 = correctAnswer - 2;
    int wrongAnswer2 = correctAnswer + 2;
    textObjectPartA.setText("" + partA);
    textObjectPartB.setText("" + partB);
    //Gives a number between 0 and 2 for the multi choice buttons
    int buttonLayout = randInt.nextInt(3);
    switch (buttonLayout) {
        case 0:
            buttonObjectChoice1.setText("" + correctAnswer);
            buttonObjectChoice2.setText("" + wrongAnswer1);
            buttonObjectChoice3.setText("" + wrongAnswer2);
            break;
        case 1:
            buttonObjectChoice2.setText("" + correctAnswer);
            buttonObjectChoice3.setText("" + wrongAnswer1);
            buttonObjectChoice1.setText("" + wrongAnswer2);
            break;
        case 2:
            buttonObjectChoice3.setText("" + correctAnswer);
            buttonObjectChoice1.setText("" + wrongAnswer1);
            buttonObjectChoice2.setText("" + wrongAnswer2);
            break;
    }//switch ends here
}//setQuestion ends here

//Updates the Score & Level for the player
void updateScoreAndLevel(int answerGiven){
    if(isCorrect(answerGiven)){
        for(int i = 1; i <= currentLevel; i++){
            currentScore = currentScore + i;
        }
        currentLevel++;
    }else{
        currentScore = 0;
        currentLevel = 1;
    }
    //Updates the Score & Level TextViews
    textObjectScore.setText("Score: " + currentScore);
    textObjectLevel.setText("Level: " + currentLevel);
    SharedPreferences sharedPreferences = getSharedPreferences("sharedPreferences",MODE_PRIVATE);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    int storedHighScore = sharedPreferences.getInt("highScore",0);
    if (currentScore>storedHighScore){
        editor.putInt("highScore",currentScore);
        editor.commit();
    }
}//updateScoreAndLevel ends here

//Sends a toast message to the player - if right = Correct!, if wrong = Wrong! :(.
boolean isCorrect(int answerGiven){
    boolean correctTrueOrFalse;
    if(answerGiven == correctAnswer){
        Toast.makeText(getApplicationContext(), "Correct!", Toast.LENGTH_LONG).show();
        correctTrueOrFalse=true;
    }else{
        Toast.makeText(getApplicationContext(), "Wrong! :(", Toast.LENGTH_LONG).show();
        correctTrueOrFalse=false;
        Intent intent = new Intent(this,HighScoreActivity.class);
        startActivity(intent);
    }
    return correctTrueOrFalse;
}//isCorrect ends here

}//TESTActivity ends here

//Highscoreactivity

public class HighScoreActivity extends AppCompatActivity {
TextView highScoreTextView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_high_score);
    SharedPreferences sharedPreferences = getSharedPreferences("sharedPreferences",MODE_PRIVATE);
    int storedHighScore = sharedPreferences.getInt("highScore",0);
    highScoreTextView=(TextView)findViewById(R.id.textHighScore);
    highScoreTextView.setText(""+storedHighScore);

    }
}