java-libGDX中的文本屏幕實現

Question

我在實現顯示和使用播放器用戶名的功能時遇到了一些麻煩。我在Windows和Android之間製作了一個跨平臺的應用程序，我試圖在他們開始輸入時展示玩家的姓名，並且可以按Enter繼續或按級別選擇 - 按鈕進入下一個屏幕。每次我按''輸入''雖然，它崩潰。另外，它不顯示或接收玩家的名字。我知道代碼不是最佳的，因爲我製作了多個表格，但我希望有人能告訴我我犯了什麼錯誤，所以它可能會起作用。提前致謝！

這是代碼：

package com.paladinzzz.game.screens; 

import com.badlogic.gdx.Gdx; 
import com.badlogic.gdx.Input; 
import com.badlogic.gdx.Screen; 
import com.badlogic.gdx.graphics.GL20; 
import com.badlogic.gdx.graphics.OrthographicCamera; 
import com.badlogic.gdx.graphics.Texture; 
import com.badlogic.gdx.graphics.g2d.BitmapFont; 
import com.badlogic.gdx.graphics.g2d.TextureRegion; 
import com.badlogic.gdx.scenes.scene2d.InputEvent; 
import com.badlogic.gdx.scenes.scene2d.Stage; 
import com.badlogic.gdx.scenes.scene2d.ui.ImageButton; 
import com.badlogic.gdx.scenes.scene2d.ui.Table; 
import com.badlogic.gdx.scenes.scene2d.ui.TextButton; 
import com.badlogic.gdx.scenes.scene2d.utils.ClickListener; 
import com.badlogic.gdx.scenes.scene2d.utils.Drawable; 
import com.badlogic.gdx.scenes.scene2d.utils.TextureRegionDrawable; 
import com.badlogic.gdx.utils.viewport.FillViewport; 
import com.paladinzzz.game.CrossplatformApp; 
import com.paladinzzz.game.util.Constants; 
import com.paladinzzz.game.audio.MusicHandler; 
import static com.badlogic.gdx.Gdx.input; 
import static com.paladinzzz.game.screens.MenuScreen.musicHandler; 


public class LoginScreen implements Screen { 

private CrossplatformApp game; 
private Stage stage; 
private ImageButton backButton, playButton; 
private Texture backTexture, playTexture, background; 
private Drawable drawableBack, drawablePlay; 
private OrthographicCamera camera; 
BitmapFont font = new BitmapFont(); 
int[] x = new int[255]; 
public static boolean inPlayscreen = false; 
public static String playername = ""; 
private boolean isConverted = false; 
private Table table, table2; 

public LoginScreen(CrossplatformApp game) { 
    this.game = game; 
    this.camera = new OrthographicCamera(); 
    this.stage = new Stage(new FillViewport(Constants.WIDTH, Constants.HEIGHT, camera)); 
    this.playTexture = new Texture("Screens/LoginScreen/LvlSelection.png"); 
    this.backTexture = new Texture("Screens/BackButton.png"); 
    this.background = new Texture("Screens/LoginScreen/loginscreen.png"); 
} 

@Override 
public void show() { 

    //Give the texture of the backButton to a new ImageButton 
    drawableBack = new TextureRegionDrawable(new TextureRegion(backTexture)); 
    backButton = new ImageButton(drawableBack); 
    backButton.addListener(new ClickListener(){ 
     @Override 
     public void clicked(InputEvent event, float x, float y) { 
      game.setScreen(new MenuScreen(game)); 
      MenuScreen.musicHandler.stopMusic(); 
     } 
    }); 

    //Give the texture of the playButton to a new ImageButton 
    drawablePlay = new TextureRegionDrawable(new TextureRegion(playTexture)); 
    playButton = new ImageButton(drawablePlay); 
    playButton.addListener(new ClickListener(){ 
     @Override 
     public void clicked(InputEvent event, float x, float y) { 
      game.setScreen(new LevelScreen(game)); 
      inPlayscreen = true; 
     } 
    }); 


    //Elements can be added here to the stage 
    input.setInputProcessor(stage); 

    //A table gets made with the button which leads to the level selection screen 
    table = new Table(); 
    table.bottom(); 
    table.setFillParent(true); 
    table.add(playButton).padBottom(40); 
    stage.addActor(table); 

    //A table gets made with the button which leads back to the main menu 
    table2 = new Table(); 
    table2.bottom(); 
    table2.setFillParent(true); 
    table2.add(backButton).padBottom(13).padRight(640); 
    table2.row(); 
    stage.addActor((table2)); 
} 

@Override 
public void render(float delta) { 

    Gdx.gl.glClearColor(1, 0, 0, 1); 
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT); 

    if(Gdx.input.isKeyJustPressed(Input.Keys.ENTER)){ 
     game.setScreen(new LevelScreen(game)); 
     inPlayscreen = true; 


     if (!isConverted){ 
      playername = playername.substring(0, 1).toUpperCase() + playername.substring(1, playername.length()).toLowerCase(); 
      isConverted = true; 
     } 
    } 

    game.batch.begin(); 

    //A possibility gets made to insert the name of the player 
    game.batch.draw(background, 0, 0, Gdx.graphics.getWidth(), Gdx.graphics.getHeight()); 
    for (int i : x) { 
     if (input.isKeyJustPressed(i)){ 
      if (i != 62 && i != 67 && i!= 66) { 
       playername += Input.Keys.toString(i).toLowerCase(); 
      } else if (i == 67 & playername.length() > 0){ 
       playername = playername.substring(0, playername.length() - 1).toLowerCase(); 
      } else { 
       playername += " "; 
      } 
     } 
    } 

    font.draw(game.batch, playername, 0, 0); 

    game.batch.end(); 
    stage.draw(); 
} 

@Override 
public void resize(int width, int height) { 

} 

@Override 
public void pause() { 

} 

@Override 
public void resume() { 

} 

@Override 
public void hide() { 

} 

@Override 
public void dispose() { 
    stage.dispose(); 

} 
} 

這是'LoginScreen ''的樣子： GameScreen

這是錯誤消息：

Exception in thread "LWJGL Application" 
java.lang.StringIndexOutOfBoundsException: String index out of range: 1 
at java.lang.String.substring(String.java:1963) 
at com.paladinzzz.game.screens.LoginScreen.render(LoginScreen.java:108) 
at com.badlogic.gdx.Game.render(Game.java:46) 
at com.paladinzzz.game.CrossplatformApp.render(CrossplatformApp.java:30) 
at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225) 
at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126) 

調試帶斷點：

Answer 1

崩潰的解決方案是這一行：

playername = playername.substring(0, 1).toUpperCase() + playername.substring(1, playername.length()).toLowerCase(); 

你的第二個字符串需要使用

playername.length()-1