Android studio NullPointerException不在我的代码中，而是在LibGDX的onResume（）中

这是堆栈跟踪：

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.epl.game, PID: 18789
    java.lang.RuntimeException: Unable to resume activity {com.epl.game/com.epl.game.AndroidLauncher}: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.badlogic.gdx.backends.android.AndroidInput.onResume()' on a null object reference
        at android.app.ActivityThread.performResumeActivity(ActivityThread.java:4205)
        at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:4237)
        at android.app.servertransaction.ResumeActivityItem.execute(ResumeActivityItem.java:52)
        at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:176)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
        at android.os.Handler.dispatchMessage(Handler.java:107)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.badlogic.gdx.backends.android.AndroidInput.onResume()' on a null object reference
        at com.badlogic.gdx.backends.android.AndroidApplication.onResume(AndroidApplication.java:300)
        at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1453)
        at android.app.Activity.performResume(Activity.java:7962)
        at android.app.ActivityThread.performResumeActivity(ActivityThread.java:4195)
        at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:4237) 
        at android.app.servertransaction.ResumeActivityItem.execute(ResumeActivityItem.java:52) 
        at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:176) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:97) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016) 
        at android.os.Handler.dispatchMessage(Handler.java:107) 
        at android.os.Looper.loop(Looper.java:214) 
        at android.app.ActivityThread.main(ActivityThread.java:7356) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:49 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930) 

这是我的主要项目

package com.epl.game;

import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.Input;
import com.badlogic.gdx.graphics.Color;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.BitmapFont;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.math.Intersector;
import com.badlogic.gdx.math.Rectangle;

import org.omg.PortableServer.POAManagerPackage.State;

import java.util.ArrayList;
import java.util.Random;

public class epl extends ApplicationAdapter {
    MyTextInputListener listener = new MyTextInputListener();
    SpriteBatch batch;
    Texture background;
    Texture[] man;
    State[] gsm;
    int batsmanState = 0;
    int pause = 0;
    float gravity = 0.2f;
    float velocity = 0;
    int manY = 0;
    Rectangle manRectangle;
    BitmapFont font1;
    BitmapFont font2;
    BitmapFont font3;
    Texture dizzy;
    int score = 0;
    int gameState = 0;
    int i1 = 0;
    int i2 = 0;
    State state0;
    State state1;
    State state2;
    State state3;
    State state4;
    State state5;

    Random random;
    String humanName;

    ArrayList<Integer> coinXs = new ArrayList<>();
    ArrayList<Integer> coinYs = new ArrayList<>();
    ArrayList<Rectangle> coinRectangles = new ArrayList<>();
    Texture coin;
    int coinCount;

    ArrayList<Integer> bombXs = new ArrayList<>();
    ArrayList<Integer> bombYs = new ArrayList<>();
    ArrayList<Rectangle> bombRectangles = new ArrayList<>();
    Texture bomb;
    int bombCount;
    PlayServices ply;

    @Override
    public void create() {
        batch = new SpriteBatch();
        background = new Texture("bg.png");
        man = new Texture[4];
        man[0] = new Texture("batsman.jpg");
        man[1] = new Texture("batsman.jpg");
        man[2] = new Texture("batsman.jpg");
        man[3] = new Texture("batsman.jpg");

        gsm = new State[6];
        gsm[0] = (state0);
        gsm[1] = (state1);
        gsm[2] = (state2);
        gsm[3] = (state3);
        gsm[4] = (state4);
        gsm[5] = (state5);


        manY = Gdx.graphics.getHeight() / 2;

        coin = new Texture("ball.png");
        bomb = new Texture("stump.jpeg");
        random = new Random();

        dizzy = new Texture("out.jpeg");

        font1 = new BitmapFont();
        font1.setColor(Color.RED);
        font1.getData().setScale(10);

        font2 = new BitmapFont();
        font2.setColor(Color.RED);
        font2.getData().setScale(10);

        font3 = new BitmapFont();
        font3.setColor(Color.RED);
        font3.getData().setScale(10);
    }

    public void makeCoin() {
        float height = random.nextFloat() * Gdx.graphics.getHeight();
        coinYs.add((int) height);
        coinXs.add(Gdx.graphics.getWidth());
    }



    public void makeBomb() {
        float height = random.nextFloat() * Gdx.graphics.getHeight();
        bombYs.add((int)height);
        bombXs.add(Gdx.graphics.getWidth());
    }
    private String myText;
    public class MyTextInputListener implements Input.TextInputListener {
        @Override
        public void input(String text) {
        }

        @Override
        public void canceled() {
            whatIsYourName();
        }

        public String getText() {
            return myText;
        }

        public void whatIsYourName() {
            Gdx.input.getTextInput(listener, "Name : ", "", "eg:Jonathan");
            humanName = listener.getText();
                gameState = 1;
            }
        }


    public epl(PlayServices ply){
        this.ply = ply;
    }

    @Override
    public void render () {
        batch.begin();
        batch.draw(background, 0, 0, Gdx.graphics.getWidth(), 
        Gdx.graphics.getHeight());

        if (gameState == 1 && state1 == null) {
            // GAME IS LIVE
            // BOMB
            if (bombCount < 250) {
                bombCount++;
            } else {
                bombCount = 0;
                makeBomb();
            }

            bombRectangles.clear();
            for (int i = 0; i < bombXs.size(); i++) {
                batch.draw(bomb, bombXs.get(i), bombYs.get(i));
                bombXs.set(i, bombXs.get(i) - 8);
                bombRectangles.add(new Rectangle(bombXs.get(i), 
                bombYs.get(i), 
                bomb.getWidth(), bomb.getHeight()));
            }

            // COINS
            if (coinCount < 100) {
                coinCount++;
            } else {
                coinCount = 0;
                makeCoin();
            }

            coinRectangles.clear();
            for (int i = 0; i < coinXs.size(); i++) {
                batch.draw(coin, coinXs.get(i), coinYs.get(i));
                coinXs.set(i, coinXs.get(i) - 4);
                coinRectangles.add(new Rectangle(coinXs.get(i), 
                coinYs.get(i), 
                coin.getWidth(), coin.getHeight()));
            }

            if (Gdx.input.justTouched()) {
                velocity = -10;
            }

            if (pause < 8) {
                pause++;
            } else {
                pause = 0;
                if (batsmanState < 3) {
                    batsmanState++;
                } else {
                    batsmanState = 0;
                }
            }

            velocity += gravity;
            manY -= velocity;

            if (manY <= 0) {
                manY = 0;
            }
        } else if (gameState == 5 && state5 == null) {
            //leaderboard
            if (Gdx.input.justTouched()){
                ply.submitScore(humanName,score);
                ply.showScore(humanName);
                gameState = 1;
            }
        }else if (gameState == 3 && state3 == null) {
            //name
            listener.whatIsYourName();
            gameState = 1;
        } else if (gameState == 0 && state0 == null) {
            // Waiting to start
                if (humanName == null){
                gameState = 3;
                }else{
                    gameState = 1;
                }
        } else if (gameState == 4 && state4 == null) {
            //final score display
            font3.draw(batch, "Score = " + score,100,1400);
            if (Gdx.input.justTouched()){
                score = 0;
                gameState = 1;
            }
        }else if (gameState == 2 && state2 == null) {
            // GAME OVER
            if (Gdx.input.justTouched()) {
                manY = Gdx.graphics.getHeight() / 2;
                velocity = 0;
                coinXs.clear();
                coinYs.clear();
                coinRectangles.clear();
                coinCount = 0;
                bombXs.clear();
                bombYs.clear();
                bombRectangles.clear();
                bombCount = 0;
                i1 = 0;
                i2 = 0;
            }
        }

        if (gameState == 2) {
            batch.draw(dizzy, Gdx.graphics.getWidth() / 2 - 
            man[batsmanState].getWidth() / 2, manY);
            if (Gdx.input.justTouched()){
                gameState = 4;
            }
        } else {
            batch.draw(man[batsmanState], Gdx.graphics.getWidth() / 2 - 
            man[batsmanState].getWidth() / 2, manY);
        }
        manRectangle = new Rectangle(Gdx.graphics.getWidth() / 2 - 
        man[batsmanState].getWidth() / 2, manY, 
        man[batsmanState].getWidth(), man[batsmanState].getHeight());

        for (int i=0; i < coinRectangles.size();i++) {
            if (Intersector.overlaps(manRectangle, coinRectangles.get(i))) {
                score++;
                i1 = random.nextInt((4 -1) + 1);
                score = score + i1;
                i2 = i1 + 1;

                coinRectangles.remove(i);
                coinXs.remove(i);
                coinYs.remove(i);
                break;
            }
        }

        for (int i=0; i < bombRectangles.size();i++) {
            if (Intersector.overlaps(manRectangle, bombRectangles.get(i))) {
                gameState = 2;
            }
        }

        font1.draw(batch, String.valueOf(score),100,200);
        font2.draw(batch, String.valueOf(i2),900,200);

        batch.end();
    }

    @Override
    public void dispose () {
        batch.dispose();
    }
}

这是我的游戏服务界面

package com.epl.game;

public interface PlayServices
{
    boolean signIn();
    void submitScore(String LeaderBoard, int highScore);
    void showScore(String LeaderBoard);
    boolean isSignedIn();
}

我是libgdx的新手，我正在尝试创建一个排行榜游戏。 我通过导入BaseGameUtils创建了它。 否则，如果你有其他方法，我可以在我的网站上创建一个全球排行榜

---

游戏请告诉我。

在

AndroidLauncher

类的

onCreate

中调用

initialize

方法至关重要。这就是为LibGDX的图形、声音和输入设置后端的原因。由于您没有调用

initialize

，因此输入类（以及图形、声音、文件等）未设置和分配，因此在达到生命周期的恢复部分时仍然为空。这将导致NullPointerException

在您的情况下，您的

onCreate

方法应该如下所示：

@覆盖
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
AndroidApplicationConfiguration配置=新的AndroidApplicationConfiguration（）；
//在此处自定义配置
初始化（新的epl（），配置）；
//您的其他设置代码。。。
}

---

注意，Java中的类名应始终以大写字母开头。这将使您的代码更易于阅读和理解。

在导致空指针异常的行上方设置一个断点，并检查您正在使用的对象的值？为什么它是空的？为什么它没有初始化？发帖提示：写问题时写有用的标题很有帮助。这有助于吸引可能帮助您的专家。如果可以的话，试着（a）省去任何乞求的信息，比如“请帮帮我”，这些信息只会让你落选；（b） 不要注意你被困了多久；（c） 不要添加关于如何提问的问题！-在评论中添加澄清问题；（d） 只需写一个问题的小摘要（例如错误消息）和您正在使用的技术。如果可以的话，保持在一两行以内。

package com.epl.game;

public interface PlayServices
{
    boolean signIn();
    void submitScore(String LeaderBoard, int highScore);
    void showScore(String LeaderBoard);
    boolean isSignedIn();
}