Question

嗨，在我的应用程序中，我有一个非常频繁出现的爆炸动画。在创建爆炸时，我从资源加载3个图像，然后一旦爆炸动画结束，我就回收这3个图像。我经常这样做，并注意到帧率下降。他们是一个更好的方法，像静态位图或其他什么？

Answer 1

我曾经做过一个应用程序，一个炸弹爆炸的简单画布。我使用了由爆炸的每个步骤组成的平铺位图，并且只绘制了它的一部分，它经常更改以创建动画效果。它会在currentTimestamp

之后自动更新步骤

所以这是爆炸类：

public class ExplosionAnimated {

private static final String TAG = ExplosionAnimated.class.getSimpleName();

private Bitmap mBitmap;
private Rect mSourceRect;
private int mFrameCountX;
private int mFrameCountY;
private int mCurrentFrame;
private long mFrameTicker;
private int mFramePeriod;

private int mSpriteWidth;
private int mSpriteHeight;

private int mX;
private int mY;

private boolean mFinished = false;

public ExplosionAnimated(Bitmap pBitmap, int pX, int pY, 
        int pFrameCountX, int pFrameCountY, int pFps) {

    this.mBitmap = pBitmap;
    this.mX = pX;
    this.mY = pY;
    this.mCurrentFrame = 0;
    this.mFrameCountX = pFrameCountX;
    this.mFrameCountY = pFrameCountY;
    this.mSpriteWidth = pBitmap.getWidth() / pFrameCountX;
    this.mSpriteHeight = pBitmap.getHeight() / pFrameCountY;
    this.mSourceRect = new Rect(0, 0, this.mSpriteWidth, this.mSpriteHeight);
    this.mFramePeriod = 1000 / pFps;
    this.mFrameTicker = 0l;
}

public void update(long gameTime) {

    if (gameTime > this.mFrameTicker + this.mFramePeriod) {
        this.mFrameTicker = gameTime;

        this.mCurrentFrame++;
        if (this.mCurrentFrame >= this.mFramePeriod) {
            this.mCurrentFrame = 0;
            this.mFinished = true;
        }
    }

    if (!this.mFinished) {

        this.mSourceRect.left = this.mCurrentFrame * this.mSpriteWidth;
        this.mSourceRect.right = this.mSourceRect.left + this.mSpriteWidth;
    }
}

public void draw(Canvas canvas) {

    Rect destRect = new Rect(this.mX, this.mY, 
            this.mX + this.mSpriteWidth, 
            this.mY + this.mSpriteHeight);
    canvas.drawBitmap(this.mBitmap, this.mSourceRect, destRect, null);
}

public boolean isFinished() {
    return this.mFinished;
}
}

这些是来自对象（Bomb.java for exemple）的方法，它开始爆炸并绘制它：

public void explode(Context pContext, Canvas pCanvas) {

    this.mState = State.EXPLODING;
    this.mExplosion = new ExplosionAnimated(this.mExplosionBitmap, 
            (int) this.mX, (int) this.mY, 7, 3, 7);
}

public void doDraw(Canvas pCanvas) {

    if (this.mState == State.EXPLODING) {

        if (this.mExplosion.isFinished()) {
            this.mState = State.EXPLODED;
        } else {
            this.mExplosion.update(System.currentTimeMillis());
            this.mExplosion.draw(pCanvas);
        }
    } else {
        pCanvas.drawBitmap(this.mBombBitmap, this.mX, this.mY, null);
    } 
}

我使用Thread和SurfaceView连续绘制炸弹（或爆炸），只给出currentTimestamp来更新爆炸。

我希望它有所帮助，如果你需要我可以展示和解释更多代码

回收位图的后果？

1 个答案: