LibGDX And​​roid偏好 - 如何将数据保存到应用程序

Question

我已经完成了一些研究，并且发现了很多关于如何在应用程序（LibGDX）中存储关卡，高分，选项等数据的文章。但这些解决方案都不适合我。我阅读了类Preferences的LibGDX描述并搜索了StackOverflow以获取如何使用它的答案。

所有我想要做的就是保存应用的水平，因此用户不必再输入应用

首选项（LibGDX）时重新开始 - https://github.com/libgdx/libgdx/wiki/Preferences

但是，当我输入了libGDX向我展示的代码。使用首选项时，是否足以输入此代码或是否还需要执行其他操作？

// LibGDX - create() 
Preferences prefs = Gdx.app.getPreferences("My Preferences"); 

// LibGDX - render() 
prefs.putString("name", "Donald Duck"); 
String name = prefs.getString("name", "No name stored"); 

prefs.putBoolean("soundOn", true); 
prefs.putInteger("highscore", 10); 

// bulk update your preferences 
prefs.flush(); 

在完成这些之后，我必须获取写入名为“我的首选项”的文件的数据并从中获取它？但是，自从LibGDX显示Windows的路径后，我在哪里可以在Android中找到该文件。

%UserProfile%/.prefs/My Preferences 

顺便说一句，我需要使用这个类之前创建了一个名为“我的首选项”文件，或将首选项创建文件本身？

LibGDX提供的代码是否按特定顺序放置？我知道我必须先创建一个Preferences参数，然后创建要存储在文件中的值。但除此之外呢？我是否使用错误的LibGDX方法将代码放入？ （create（），render（））。

我试图刚刚从一个链接编写代码

Preferences pref = Gdx.app.getPreferences("somefile"); 
pref.putString("name", "Menyo"); 
pref.putInteger("level", 20); 

只是为了看看它的工作。但它似乎并不像它那样。我在代码中丢失了什么吗？或者它是我缺少的需要创建的文件？

研究链接：

Using LibGDX with Android Preferences

Android libgdx preferences not working

http://www.badlogicgames.com/forum/viewtopic.php?f=11&t=6365#p32981

How do apps save data

Android libgdx preferences not working

编辑：

我得到了我问的解释，但我需要更多的信息。在我的LibGDX应用程序中，我有方法渲染，并且在该方法中我有menu（），game（）。我不应该在渲染方法中调用首选项？它们应该在哪里被调用，因为如果它们在create（）方法中，它们只会被调用一次？

我想我退出应用程序时可以调用Preferences（Prefs）方法来保存关卡数据。但它不起作用，应用程序仍然回到第一级。所以我决定在这里发布我的代码，这样每个人都可以看到我做错了什么。

（可以使用CTRL + F找到变量 “水平” 和 “首选项” 无处不在的代码）

package com.game.whatstheanswer; 

import com.badlogic.gdx.ApplicationAdapter; 
import com.badlogic.gdx.Gdx; 
import com.badlogic.gdx.Input; 
import com.badlogic.gdx.InputProcessor; 
import com.badlogic.gdx.graphics.Color; 
import com.badlogic.gdx.graphics.GL20; 
import com.badlogic.gdx.graphics.Texture; 
import com.badlogic.gdx.graphics.g2d.BitmapFont; 
import com.badlogic.gdx.graphics.g2d.GlyphLayout; 
import com.badlogic.gdx.graphics.g2d.SpriteBatch; 
import com.badlogic.gdx.graphics.g2d.freetype.FreeTypeFontGenerator; 
import com.badlogic.gdx.graphics.glutils.ShapeRenderer; 

public class MyGdxGame extends ApplicationAdapter implements InputProcessor { 
private SpriteBatch batch; 

private GAME STATE; 
private BitmapFont font; 
private BitmapFont fontTextAdjustment; 
private GlyphLayout layout; 
private String message; 

private Texture logo; 
private Texture questionmarks; 
private Texture keyboard; 

private Texture btnReset; 
private Texture btnMenu; 

@Override 
public void create() { 
    batch = new SpriteBatch(); 

    // Configure the Android keyboard 
    Gdx.input.setInputProcessor(this); 
    isAndroidKeyboardShowing = true; 

    // Menu logo 
    logo = new Texture("logo.png"); 
    questionmarks = new Texture("questionmarks.png"); 
    //level = 1; 

    STATE = GAME.MENU; 
    btnPlay = new Texture("play.png"); 
    btnInfo = new Texture("info.png"); 
    btnQuit = new Texture("quit.png"); 

    // The game over menu 
    btnMenu = new Texture("menu.png"); 
    btnReset = new Texture("reset.png"); 

    FreeTypeFontGenerator generator = new FreeTypeFontGenerator(Gdx.files.internal("Amethysta.ttf")); 
    FreeTypeFontGenerator.FreeTypeFontParameter parameter = new FreeTypeFontGenerator.FreeTypeFontParameter(); 
    parameter.size = 66; 
    font = generator.generateFont(parameter); // font size 66 pixels 

    parameter.size = 28; 
    fontTextAdjustment = generator.generateFont(parameter); 
    generator.dispose(); // don't forget to dispose to avoid memory leaks! 


    layout = new GlyphLayout(); 

    keyboard = new Texture("keyboard/keyboard.png"); 

    userInput = ""; 
    message = ""; 
    /* 
    prefs = Gdx.app.getPreferences("com.game.whatstheanswer.settings"); 
    String name = prefs.getString("Level", "0");*/ 

    prefs = new Prefs(); 
} 

private Prefs prefs; 
//private static Preferences prefs; 

//private String letter; 
private String userInput; 
private String answer; 
private int level; 

@Override 
public void render() { 
    Gdx.gl.glClearColor(255, 255, 255, 1); 
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); 

    batch.begin(); 

    //STATE = GAME.OVER; 
    switch (STATE) { 
     case MENU: menu(); break; 
     case PLAY: 
      Gdx.gl.glClearColor(0, 0, 0, 1); 
      Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); 
      game(); 
      break; 
     case PAUSE: break; 
     case RESUME: break; 
     case OVER: gameComplete(); break; 
    } 
    batch.end(); 
} 

private Texture btnPlay, btnInfo, btnQuit; 
private void menu() { 
    // Draw a colorful background 
    batch.draw(logo, Gdx.graphics.getWidth()/2 - logo.getWidth()/2, Gdx.graphics.getHeight() - logo.getHeight()); 
    batch.draw(questionmarks, Gdx.graphics.getWidth()/2 - logo.getWidth()/2, Gdx.graphics.getHeight() - logo.getHeight() - 460); 
    batch.draw(btnPlay, Gdx.graphics.getWidth()/2 - btnPlay.getWidth()/2, 600); 
    batch.draw(btnInfo, Gdx.graphics.getWidth()/2 - btnInfo.getWidth()/2, 400); 
    batch.draw(btnQuit, Gdx.graphics.getWidth()/2 - btnQuit.getWidth()/2, 200); 

    // Play button 
    if (Gdx.input.justTouched() && 
      Gdx.input.getX() >= Gdx.graphics.getWidth()/2 - btnPlay.getWidth()/2 && 
      Gdx.input.getX() <= (Gdx.graphics.getWidth()/2 - btnPlay.getWidth()/2) + btnPlay.getWidth() && 
      Gdx.input.getY() >= Gdx.graphics.getHeight() - 600 - btnPlay.getHeight() && 
      Gdx.input.getY() <= Gdx.graphics.getHeight() - 600) { 
     STATE = GAME.PLAY; 
     isAndroidKeyboardShowing = true; 
     System.out.println("Main Menu: Play"); 
    } 

    // Info button 
    if (Gdx.input.justTouched() && 
      Gdx.input.getX() >= Gdx.graphics.getWidth()/2 - btnPlay.getWidth()/2 && 
      Gdx.input.getX() <= (Gdx.graphics.getWidth()/2 - btnPlay.getWidth()/2) + btnPlay.getWidth() && 
      Gdx.input.getY() >= Gdx.graphics.getHeight() - 400 - btnPlay.getHeight() && 
      Gdx.input.getY() <= Gdx.graphics.getHeight() - 400) { 
     System.out.println("Main Menu: Info"); 
    } 

    // Quit button 
    if (Gdx.input.justTouched() && 
      Gdx.input.getX() >= Gdx.graphics.getWidth()/2 - btnPlay.getWidth()/2 && 
      Gdx.input.getX() <= (Gdx.graphics.getWidth()/2 - btnPlay.getWidth()/2) + btnPlay.getWidth() && 
      Gdx.input.getY() >= Gdx.graphics.getHeight() - 200 - btnPlay.getHeight() && 
      Gdx.input.getY() <= Gdx.graphics.getHeight() - 200) { 
     level = prefs.getLevel(); 
     Gdx.app.exit(); 
     System.out.println("Main Menu: Quit"); 
    } 
} 

/* 
public void increaseLevel() { 
    prefs.putString("Level", String.valueOf(level)); 
    prefs.flush(); 
    Gdx.app.log("level", level+""); 
}*/ 

private void game() { 
    // Set the color of the text 
    font.setColor(Color.WHITE); 

    level = prefs.getLevel(); 
    /* 
    font.draw(batch, "MENU", 120, Gdx.graphics.getHeight() - 80); 
    font.draw(batch, "CLEAR", 420, Gdx.graphics.getHeight() - 80); 
    font.draw(batch, "SOLVE", 740, Gdx.graphics.getHeight() - 80);*/ 

    font.draw(batch, "MENU", Gdx.graphics.getWidth()/7, Gdx.graphics.getHeight() - 80); 
    font.draw(batch, "CLEAR", (((7/2)*Gdx.graphics.getWidth()/7)), Gdx.graphics.getHeight() - 80); 
    font.draw(batch, "SOLVE", 5*Gdx.graphics.getWidth()/7, Gdx.graphics.getHeight() - 80); 

    System.out.println(userInput); 

    layout.setText(font, "Question " + level); 
    font.draw(batch, "Question " + level, Gdx.graphics.getWidth()/2 - layout.width/2, 5*Gdx.graphics.getHeight()/6); 

    switch (level) { 
     default: break; 
     // my cases are in here, removed them to shortned the code 
     case 1: break; 
     case 2: break; 
     ... 
     case n: break; 
    } 

    // The user input 
    layout.setText(font, userInput); 
    font.draw(batch, userInput, Gdx.graphics.getWidth()/2 - layout.width/2, 880); 

    //layout.setText(font, letter = "Q"); 

    drawnKeyboard(); 
    inputKeyboard(); 

    ShapeRenderer shapeRenderer = new ShapeRenderer(); 
    shapeRenderer.begin(ShapeRenderer.ShapeType.Line); 
    shapeRenderer.setColor(com.badlogic.gdx.graphics.Color.WHITE); 

    // Horizontal line, user input above it 
    shapeRenderer.rectLine(110, 800, Gdx.graphics.getWidth() - 110, 800, 4); // shapeRenderer.rectLine(120, 800, 940, 800, 4); 

    shapeRenderer.end(); 

} 

// Questions on one line 
private void msgOneLine(String message, String answer) { 
    this.message = message; 
    this.answer = answer; 
    layout.setText(font, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width/2, 1200); 
} 

private void msgTwoLines(String msg1, String msg2, String answer) { 
    this.message = msg1; 
    this.answer = answer; 
    layout.setText(fontTextAdjustment, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width - 80, 1200); 
    message = msg2; 
    layout.setText(fontTextAdjustment, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width - 80, 1200 - layout.height - 50); 
} 

private void msgThreeLines(String msg1, String msg2, String msg3, String answer) { 
    this.message = msg1; 
    this.answer = answer; 
    layout.setText(fontTextAdjustment, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width - 80, 1200); 

    message = msg2; 
    layout.setText(fontTextAdjustment, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width - 80, 1200 - layout.height - 50); 

    message = msg3; 
    layout.setText(fontTextAdjustment, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width - 80, 1200 - layout.height - 120); 
} 

private void msgFourLines(String msg1, String msg2, String msg3, String msg4, String answer) { 
    this.message = msg1; 
    this.answer = answer; 
    layout.setText(fontTextAdjustment, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width - 80, 1200); 

    message = msg2; 
    layout.setText(fontTextAdjustment, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width - 80, 1200 - layout.height - 50); 

    message = msg3; 
    layout.setText(fontTextAdjustment, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width - 80, 1200 - layout.height - 120); 

    message = msg4; 
    layout.setText(fontTextAdjustment, message); 
    font.draw(batch, message, (Gdx.graphics.getWidth()/2) - layout.width - 80, 1200 - layout.height - 190); 
} 

private void drawnKeyboard() { 

    batch.draw(keyboard, 440, 400); 

} 

private boolean isAndroidKeyboardShowing; 
private void inputKeyboard() { 
    if (Gdx.input.justTouched()) { 
     System.out.println("(" + Gdx.input.getX() + ", " + Gdx.input.getY() + ")"); 

     // ####################### BOTTOM BUTTONS ####################### 

     // Menu button 
     if (Gdx.input.getX() > 76 && Gdx.input.getX() < 350 && Gdx.input.getY() > 40 && Gdx.input.getY() < 116) { 
      STATE = GAME.MENU; 
      isAndroidKeyboardShowing = false; 
     } 

     // Clear button 
     if (Gdx.input.getX() > 350 && Gdx.input.getX() < 676 && Gdx.input.getY() > 40 && Gdx.input.getY() < 116) { 
      userInput = ""; 
     } 

     // Solve button 
     if (Gdx.input.getX() > 676 && Gdx.input.getX() < 976 && Gdx.input.getY() > 40 && Gdx.input.getY() < 116) { 
      System.out.println("SOLVE"); 
      solve(); 
     } 

    } 

    // Android keyboard 
    Gdx.input.setOnscreenKeyboardVisible(isAndroidKeyboardShowing); 
} 

// The solve algorithm 
private void solve() { 

    if (userInput.equalsIgnoreCase(answer)) { 
     //level++; 
     prefs.increaseLevel(); 
     userInput = ""; 
    } 

    userInput = ""; 
} 

@Override 
public boolean keyDown(int keycode) { 

    switch (keycode) { 
     // Numbers 
     case Input.Keys.NUM_0: userInput += '0'; break; 
     case Input.Keys.NUM_1: userInput += '1'; break; 
     case Input.Keys.NUM_2: userInput += '2'; break; 
     case Input.Keys.NUM_3: userInput += '3'; break; 
     case Input.Keys.NUM_4: userInput += '4'; break; 
     case Input.Keys.NUM_5: userInput += '5'; break; 
     case Input.Keys.NUM_6: userInput += '6'; break; 
     case Input.Keys.NUM_7: userInput += '7'; break; 
     case Input.Keys.NUM_8: userInput += '8'; break; 
     case Input.Keys.NUM_9: userInput += '9'; break; 

     // All english letters 
     case Input.Keys.A: userInput += 'A'; break; 
     case Input.Keys.B: userInput += 'B'; break; 
     case Input.Keys.C: userInput += 'C'; break; 
     case Input.Keys.D: userInput += 'D'; break; 
     case Input.Keys.E: userInput += 'E'; break; 
     case Input.Keys.F: userInput += 'F'; break; 
     case Input.Keys.G: userInput += 'G'; break; 
     case Input.Keys.H: userInput += 'H'; break; 
     case Input.Keys.I: userInput += 'I'; break; 
     case Input.Keys.J: userInput += 'J'; break; 
     case Input.Keys.K: userInput += 'K'; break; 
     case Input.Keys.L: userInput += 'L'; break; 
     case Input.Keys.M: userInput += 'M'; break; 
     case Input.Keys.N: userInput += 'N'; break; 
     case Input.Keys.O: userInput += 'O'; break; 
     case Input.Keys.P: userInput += 'P'; break; 
     case Input.Keys.Q: userInput += 'Q'; break; 
     case Input.Keys.R: userInput += 'R'; break; 
     case Input.Keys.S: userInput += 'S'; break; 
     case Input.Keys.T: userInput += 'T'; break; 
     case Input.Keys.U: userInput += 'U'; break; 
     case Input.Keys.V: userInput += 'V'; break; 
     case Input.Keys.W: userInput += 'W'; break; 
     case Input.Keys.X: userInput += 'X'; break; 
     case Input.Keys.Y: userInput += 'Y'; break; 
     case Input.Keys.Z: userInput += 'Z'; break; 

     // Special keys 
     case Input.Keys.ENTER: solve(); break; 

     case Input.Keys.BACKSPACE: 
      if (userInput.length() > 0) 
       userInput = userInput.substring(0, userInput.length()-1); 
      break; 
    } 

    return true; 
} 

private void gameComplete() { 
    font.setColor(Color.BLACK); 
    layout.setText(font, "Play again? Reset?"); 
    font.draw(batch, "Play again? Reset?", Gdx.graphics.getWidth()/2 - layout.width/2, Gdx.graphics.getHeight() - 400); 

    batch.draw(btnMenu, Gdx.graphics.getWidth()/2 - btnMenu.getWidth()/2, 600); 
    batch.draw(btnReset, Gdx.graphics.getWidth()/2 - btnReset.getWidth()/2, 400); 
    batch.draw(btnQuit, Gdx.graphics.getWidth()/2 - btnQuit.getWidth()/2, 200); 

    // Menu button 
    if (Gdx.input.justTouched() && 
      Gdx.input.getX() >= Gdx.graphics.getWidth()/2 - btnMenu.getWidth()/2 && 
      Gdx.input.getX() <= (Gdx.graphics.getWidth()/2 - btnMenu.getWidth()/2) + btnMenu.getWidth() && 
      Gdx.input.getY() >= Gdx.graphics.getHeight() - 600 - btnMenu.getHeight() && 
      Gdx.input.getY() <= Gdx.graphics.getHeight() - 600) { 
     STATE = GAME.MENU; 
     System.out.println("Game Over Menu: Menu"); 
    } 

    // Reset button 
    if (Gdx.input.justTouched() && 
      Gdx.input.getX() >= Gdx.graphics.getWidth()/2 - btnReset.getWidth()/2 && 
      Gdx.input.getX() <= (Gdx.graphics.getWidth()/2 - btnReset.getWidth()/2) + btnReset.getWidth() && 
      Gdx.input.getY() >= Gdx.graphics.getHeight() - 400 - btnReset.getHeight() && 
      Gdx.input.getY() <= Gdx.graphics.getHeight() - 400) { 
     level = 1; 
     System.out.println("Game Over Menu: Reset"); 
    } 

    // Quit button 
    if (Gdx.input.justTouched() && 
      Gdx.input.getX() >= Gdx.graphics.getWidth()/2 - btnQuit.getWidth()/2 && 
      Gdx.input.getX() <= (Gdx.graphics.getWidth()/2 - btnQuit.getWidth()/2) + btnQuit.getWidth() && 
      Gdx.input.getY() >= Gdx.graphics.getHeight() - 200 - btnQuit.getHeight() && 
      Gdx.input.getY() <= Gdx.graphics.getHeight() - 200) { 
     Gdx.app.exit(); 
     System.out.println("Game Over Menu: Quit"); 
    } 
} 

// Usual input 
@Override 
public boolean keyUp(int keycode) { 
    return false; 
} 

@Override 
public boolean keyTyped(char character) { 
    return false; 
} 

@Override 
public boolean touchDown(int screenX, int screenY, int pointer, int button) { 
    return false; 
} 

@Override 
public boolean touchUp(int screenX, int screenY, int pointer, int button) { 
    return false; 
} 

@Override 
public boolean touchDragged(int screenX, int screenY, int pointer) { 
    return false; 
} 

@Override 
public boolean mouseMoved(int screenX, int screenY) { 
    return false; 
} 

@Override 
public boolean scrolled(int amount) { 
    return false; 
} 

}

编辑 对不起的人，我有试图实现你给我的代码，但仍然做错了什么。我的所有方法game（），menu（），gameComplete（）都在batch.begin（）和batch.end（）之间的render（）方法中。 我需要在关闭应用程序时保存关卡。

但是我如何检查确实发生了一些事情，以便知道我的首选项已创建？此外，如果不建议在render（）方法中调用偏好，我应该在哪里调用它们？ create（）方法只调用一次偏好，因此不会保存关卡。

Answer 1

无需创建My Preferences，它创建它自己。偏好相关的工作不应该在render方法中完成。

在Android上，使用了系统的[SharedPreferences] [1]类。这意味着首选项可以在应用程序更新后保留，但在卸载应用程序时会被删除。 SharedPreferences将私有原始数据存储在键值对中。

public class TestGame2 extends Game { 

    public Prefs prefs; 

    @Override 
    public void create() { 

     prefs=new Prefs(); 

     System.out.printf("Current Sound Status"+prefs.hasSound()); 

     // I need to to change sound Status 
     prefs.setSound(false); 

     //Now sound is off 

    } 

    public void playSound(){ 

     if(prefs.hasSound()) { 
      Sound sound=Gdx.audio.newSound("...."); 
      sound.play(); 
     } 
    } 

    public void startGame(){ 

     //what is my previous highest saved game level, last time 

     int level=prefs.getLevel(); 
    } 

    public void levelCompleted(){ 

     // wow last Level completed so now i need to increase level 
     prefs.increaseLevel(); 
    } 
} 

而且偏好设置是：

public class Prefs { 

    private Preferences pref ; 
    private boolean hasSound; 
    private int completedLevel; 

    public Prefs(){ 
     pref = Gdx.app.getPreferences("My Preferences"); 
     hasSound = pref.getBoolean("hasSound",true); 
     completedLevel=pref.getInteger("level",0); 

    } 

    public void setSound(boolean hasSound){ 
     this.hasSound=hasSound; 
     pref.putBoolean("hasSound",hasSound); 
     pref.flush(); 
    } 

    public boolean hasSound(){ 
     return hasSound; 
    } 

    //should be called once when we need to increase my level 
    public void increaseLevel(){ 
     completedLevel++; 
     pref.putInteger("level",completedLevel); 
     pref.flush(); 
    } 

    public int getLevel(){ 
     return completedLevel; 
    } 
} 

编辑

使用计数器一样。

boolean isDataSaved; 

private void gameComplete() { // your method 

    if(!isDataSaved){ 
     levelCompleted(); 
     isDataSaved=true; 
    } 

    font.setColor(Color.BLACK); 
    layout.setText(font, "Play again? Reset?"); 
} 

private void menu() { 
    isDataSaved=false; 
} 

而你已经在你的game方法使用的startGame()代码。