java - libgdx动画 Sprite 没有方法错误

Question

每当我将用于动画目的的 Sprite 图集上传到 overlaps2d 版本 0.1.2-快照中的场景中时。我的应用程序崩溃并显示以下行(略有编辑):

java.lang.NoSuchMethodError: No virtual method getKeyFrame(F)Lcom/badlogic/gdx/graphics/g2d/TextureRegion; in class Lcom/badlogic/gdx/graphics/g2d/Animation; or its super classes (declaration of 'com.badlogic.gdx.graphics.g2d.Animation' appears in /data/data/xxx.xxx.xxx/files/instant-run/dex/slice-gdx-1.9.5_xxx-classes.dex)

它指向我代码中的这一行:

sceneLoader.getEngine().update(Gdx.graphics.getDeltaTime());

这会不会是版本不匹配的问题，因为 overlap2d 已经一年多没有更新了，而 libgdx 大约一个月前才更新过？崩溃只发生在动画图像上，否则应用程序运行正常。我查看了错误所指的 libgdx 文件，它看起来是这样的:

package com.badlogic.gdx.graphics.g2d;

import com.badlogic.gdx.math.MathUtils;
import com.badlogic.gdx.utils.Array;

public class Animation<T> {

/** Defines possible playback modes for an {@link Animation}. */
public enum PlayMode {
    NORMAL,
    REVERSED,
    LOOP,
    LOOP_REVERSED,
    LOOP_PINGPONG,
    LOOP_RANDOM,
}

/** Length must not be modified without updating {@link #animationDuration}. See {@link #setKeyFrames(T[])}. */
T[] keyFrames;
private float frameDuration;
private float animationDuration;
private int lastFrameNumber;
private float lastStateTime;

private PlayMode playMode = PlayMode.NORMAL;

/** Constructor, storing the frame duration and key frames.
 * 
 * @param frameDuration the time between frames in seconds.
 * @param keyFrames the objects representing the frames. */
public Animation (float frameDuration, Array<? extends T> keyFrames) {
    this.frameDuration = frameDuration;
    T[] frames = (T[]) new Object[keyFrames.size];
    for (int i = 0, n = keyFrames.size; i < n; i++) {
        frames[i] = keyFrames.get(i);
    }
    setKeyFrames(frames);
}

/** Constructor, storing the frame duration and key frames.
 * 
 * @param frameDuration the time between frames in seconds.
 * @param keyFrames the objects representing the frames. */
public Animation (float frameDuration, Array<? extends T> keyFrames, PlayMode playMode) {
    this(frameDuration, keyFrames);
    setPlayMode(playMode);
}

/** Constructor, storing the frame duration and key frames.
 * 
 * @param frameDuration the time between frames in seconds.
 * @param keyFrames the objects representing the frames. */
public Animation (float frameDuration, T... keyFrames) {
    this.frameDuration = frameDuration;
    setKeyFrames(keyFrames);
}

/** Returns a frame based on the so called state time. This is the amount of seconds an object has spent in the
 * state this Animation instance represents, e.g. running, jumping and so on. The mode specifies whether the animation is
 * looping or not.
 * 
 * @param stateTime the time spent in the state represented by this animation.
 * @param looping whether the animation is looping or not.
 * @return the frame of animation for the given state time. */
public T getKeyFrame (float stateTime, boolean looping) {
    // we set the play mode by overriding the previous mode based on looping
    // parameter value
    PlayMode oldPlayMode = playMode;
    if (looping && (playMode == PlayMode.NORMAL || playMode == PlayMode.REVERSED)) {
        if (playMode == PlayMode.NORMAL)
            playMode = PlayMode.LOOP;
        else
            playMode = PlayMode.LOOP_REVERSED;
    } else if (!looping && !(playMode == PlayMode.NORMAL || playMode == PlayMode.REVERSED)) {
        if (playMode == PlayMode.LOOP_REVERSED)
            playMode = PlayMode.REVERSED;
        else
            playMode = PlayMode.LOOP;
    }

    T frame = getKeyFrame(stateTime);
    playMode = oldPlayMode;
    return frame;
}

/** Returns a frame based on the so called state time. This is the amount of seconds an object has spent in the
 * state this Animation instance represents, e.g. running, jumping and so on using the mode specified by
 * {@link #setPlayMode(PlayMode)} method.
 * 
 * @param stateTime
 * @return the frame of animation for the given state time. */
public T getKeyFrame (float stateTime) {
    int frameNumber = getKeyFrameIndex(stateTime);
    return keyFrames[frameNumber];
}

/** Returns the current frame number.
 * @param stateTime
 * @return current frame number */
public int getKeyFrameIndex (float stateTime) {
    if (keyFrames.length == 1) return 0;

    int frameNumber = (int)(stateTime / frameDuration);
    switch (playMode) {
    case NORMAL:
        frameNumber = Math.min(keyFrames.length - 1, frameNumber);
        break;
    case LOOP:
        frameNumber = frameNumber % keyFrames.length;
        break;
    case LOOP_PINGPONG:
        frameNumber = frameNumber % ((keyFrames.length * 2) - 2);
        if (frameNumber >= keyFrames.length) frameNumber = keyFrames.length - 2 - (frameNumber - keyFrames.length);
        break;
    case LOOP_RANDOM:
        int lastFrameNumber = (int) ((lastStateTime) / frameDuration);
        if (lastFrameNumber != frameNumber) {
            frameNumber = MathUtils.random(keyFrames.length - 1);
        } else {
            frameNumber = this.lastFrameNumber;
        }
        break;
    case REVERSED:
        frameNumber = Math.max(keyFrames.length - frameNumber - 1, 0);
        break;
    case LOOP_REVERSED:
        frameNumber = frameNumber % keyFrames.length;
        frameNumber = keyFrames.length - frameNumber - 1;
        break;
    }

    lastFrameNumber = frameNumber;
    lastStateTime = stateTime;

    return frameNumber;
}

/** Returns the keyframes[] array where all the frames of the animation are stored.
 * @return The keyframes[] field. */
public T[] getKeyFrames () {
    return keyFrames;
}

protected void setKeyFrames (T... keyFrames) {
    this.keyFrames = keyFrames;
    this.animationDuration = keyFrames.length * frameDuration;
}

/** Returns the animation play mode. */
public PlayMode getPlayMode () {
    return playMode;
}

/** Sets the animation play mode.
 * 
 * @param playMode The animation {@link PlayMode} to use. */
public void setPlayMode (PlayMode playMode) {
    this.playMode = playMode;
}

/** Whether the animation would be finished if played without looping (PlayMode#NORMAL), given the state time.
 * @param stateTime
 * @return whether the animation is finished. */
public boolean isAnimationFinished (float stateTime) {
    int frameNumber = (int)(stateTime / frameDuration);
    return keyFrames.length - 1 < frameNumber;
}

/** Sets duration a frame will be displayed.
 * @param frameDuration in seconds */
public void setFrameDuration (float frameDuration) {
    this.frameDuration = frameDuration;
    this.animationDuration = keyFrames.length * frameDuration;
}

/** @return the duration of a frame in seconds */
public float getFrameDuration () {
    return frameDuration;
}

/** @return the duration of the entire animation, number of frames times frame duration, in seconds */
public float getAnimationDuration () {
    return animationDuration;
}

据我了解，获取关键帧是从图像图集中检索帧并根据时间更改它以产生运动的错觉。

Answer 1

使用以前版本的 libgdx，即 1.9.4。在 libgdx 版本 1.9.5 中，动画类有一些变化，未随 overlap2d 快照版本更新，因此您遇到了问题。

在根项目的build.gradle中降级版本。希望这可能有所帮助。

谢谢。