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Storing data with Shared preferences

 原文  2017-03-04 17:47:55  7   2    java/ android

Question

For past 3 days I've literally spent 6-8h/day on searching, reading and executing all kinds of examples regarding Shared Preferences without any success. I've come to a dead end...been very frustrating! My issue is as follows:

- Objective: I'm currently doing a very basic math game, where the player will be given a (random) equation, with two numbers multiplied with eachother. The player will then give an answer by simply pressing one of three option-buttons (one including the correct answere). Scores are added for each correct answers.

- Problem: NOW, I want to include a High Score for the game to store the highest score. How do I get around to store my data using shared preferences or any other working method.

"Score:" (@+id/textScore) is my TextView that contains the score (TESTActivity.java). "Top Scores" (@+id/textTopScores) is my TextView where I want to store my high score (HighScoreActivity.java).

- Structure of the App: 

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

2 answers

solution1
 4  2017-03-04 17:56:57

Actually main problem is here. 

 //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) you are using high score as key which will be change, but shared preference can be get by same key which is used a time of storing.

You should store like this 

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

Get score by-> 

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

Main point is KEY should be same

solution2
 2 ACCPTED  2017-03-04 18:11:05

//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);


    }
}

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