NullPointerException異常是Java的嘗試與libgdx

-3

我是說我想創建我的球員，他的動畫一個NullPointerException動畫。我真的不明白什麼是錯的。下面是代碼：NullPointerException異常是Java的嘗試與libgdx

package com.sheep.game.Sprites; 

import com.badlogic.gdx.Gdx; 
import com.badlogic.gdx.graphics.Texture; 
import com.badlogic.gdx.graphics.g2d.Animation; 
import com.badlogic.gdx.graphics.g2d.Sprite; 
import com.badlogic.gdx.graphics.g2d.TextureRegion; 
import com.sheep.game.Screens.PlayScreen; 

public class Player extends Sprite { 

    float elapsedTime = 0; 

    public Animation<TextureRegion> animation; 
    public Texture sheepLoop2; 
    TextureRegion[] animationFrames; 

    public Sprite spr_player; 

    private PlayScreen screen; 

    public Player(PlayScreen screen) { 

     this.screen = screen; 

     sheepLoop2 = new Texture("sheepLoop2.png"); 

     TextureRegion[][] frames = TextureRegion.split(sheepLoop2, 33, 21); 

     animationFrames = new TextureRegion[2]; 
     int index = 0; 

     for(int i = 0; i < 1; i++) { 
      for(int j = 0; j < 1; j++) { 
       animationFrames[index++] = frames[j][i]; 
      } 
     } 

     animation = new Animation<TextureRegion>(1f/30f, animationFrames); 

     spr_player = new Sprite(sheepLoop2); 



    } 

    public void update() { 

     spr_player.setX(10); 
     spr_player.setY(100); 
     spr_player.setRegion(animation.getKeyFrame(elapsedTime,true)); 

    } 

    public void render() { 

     elapsedTime += Gdx.graphics.getDeltaTime(); 

    } 

    public Texture getSheepLoop2() { 
     return sheepLoop2; 
    } 
}

而且堆棧跟蹤是：

Exception in thread "LWJGL Application" java.lang.NullPointerException 
    at com.badlogic.gdx.graphics.g2d.TextureRegion.setRegion(TextureRegion.java:112) 
    at com.sheep.game.Sprites.Player.update(Player.java:53) 
    at com.sheep.game.Screens.PlayScreen.update(PlayScreen.java:61) 
    at com.sheep.game.Screens.PlayScreen.render(PlayScreen.java:84) 
    at com.badlogic.gdx.Game.render(Game.java:46) 
    at com.sheep.game.SheepGame.render(SheepGame.java:28) 
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop(LwjglApplication.java:225) 
    at com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run(LwjglApplication.java:126)

來源

2017-04-25 Cjinks

的可能的複製[什麼是空指針異常，怎麼解決呢？（HTTP：//計算器.COM /問題/ 218384 /什麼 - 是 - 一 - NullPointerException異常和知識-DO-I-FIX-IT） – csmckelvey

'異常在線程com.sheep.game.Sprites 「LWJGL應用」顯示java.lang.NullPointerException。 Player.update（Player.java:53）'哪一行是53？那裏可能是空的？當你在該區域進行調試時，你會發現什麼？ – csmckelvey

檢查animationFrame是否已正確初始化。 – Serhiy

animationFrames = new TextureRegion[2]; // having size 2 array initialisation not TextureRegion 

for(int i = 0; i < 1; i++) { 
    for(int j = 0; j < 1; j++) { 
     animationFrames[index++] = frames[j][i]; //run once according to your condition 
    } 
}

通過上面的循環，你只初始化第一指標，循環後animationFrames[1]是空

異常這裏

animation.getKeyFrame(elapsedTime,true) //return second TextureRegion that is still null

將null設置爲TextureRegion至Sprite。

spr_player.setRegion(animation.getKeyFrame(elapsedTime,true));

編輯

如果兩個精靈幀水平排列

for(int i = 0; i < 1; i++) { 
    for(int j = 0; j < 2; j++) { 
     animationFrames[index++] = frames[i][j]; 
    } 
}

來源

2017-04-25 20:47:07 Aryan

我只是在學習，我不明白你的意思？我該如何解決？ – Cjinks

sheepLoop2.png中有多少個精靈幀？ – Aryan

有兩個幀都是33 x 21像素 – Cjinks

NullPointerException異常是Java的嘗試與libgdx

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