Question

我想尝试一个简单的图像动画。我想让它看起来好像直升机的螺旋桨叶片正在转动。我有三张直升机的图像，我根据动画进度显示其中一个图像。问题是所有三个图像最终彼此重叠，而不是一次只显示一个图像，从而创建动画。这就是我到目前为止所做的，我甚至尝试通过执行canvas.drawColor（Color.BLACK）来清除画布，但这将清除整个画布，这不是我想要的。

这就是我所拥有的：

1）在View类中：

静态类直升机{ private long mLastUpdate; private long mProgress = 0; 私人最终浮动mX; 私人最终浮动mY;

    private final Bitmap mHelicopter1;
    private final Bitmap mHelicopter2;
    private final Bitmap mHelicopter3;
    private final float mRadius;

    Helicopter(long mLastUpdate, float mX, float mY,
              Bitmap helicopter1, Bitmap helicopter2, Bitmap helicopter3) {
        this.mLastUpdate = mLastUpdate;
        this.mX = mX;
        this.mY = mY;
        this.mHelicopter1 = helicopter1;
        this.mHelicopter2 = helicopter2;
        this.mHelicopter3 = helicopter3;
        mRadius = ((float) mHelicopter1.getWidth()) / 2f;

    }

    public void update(long now) {
        mProgress += (now - mLastUpdate);

        if(mProgress >= 400L)
        {
         mProgress = 0;
        }
        mLastUpdate = now;
    }

    public void setNow(long now) {
        mLastUpdate = now;
    }

    public void draw(Canvas canvas, Paint paint) 
    {       

        if (mProgress < 150L) 
        {
            canvas.drawBitmap(mHelicopter1, mX - mRadius, mY - mRadius, paint);
        } 
        else if (mProgress < 300L) 
        {
            canvas.drawBitmap(mHelicopter2, mX - mRadius, mY - mRadius, paint);

        } 
        else if(mProgress < 400L)
        {
         canvas.drawBitmap(mHelicopter3, mX - mRadius, mY - mRadius, paint);
        }

    }

    public boolean done() {
        return mProgress > 700L;
    }
}

private ArrayList<Helicopter> mHelicopters = new ArrayList<Helicopter>();

2）这是在线程的run（）中调用的：

private void doDraw(Canvas canvas) 
    {
     final long now = SystemClock.elapsedRealtime();

        canvas.save();

        for (int i = 0; i < mHelicopters.size(); i++) {
            final Helicopter explosion = mHelicopters.get(i);
            explosion.update(now);
        }

        for (int i = 0; i < mHelicopters.size(); i++) {
            final Helicopter explosion = mHelicopters.get(i);
            explosion.draw(canvas, mPaint);
        }

        canvas.restore();
    }

有人能帮帮我吗？我在网上看了很多关于动画的例子，它们似乎总是涉及文本，而不是图像。感谢。

Answer 1

通常绘制画布的线程会重绘整个画布和所有道具/演员。这样，如果您增加直升机刀片图像索引，它将在重绘其余画布后绘制到位。类似于：Background-＆gt; Helicopter-＆gt; Blade1 next iteration Background-＆gt; Helicopter-＆gt; Blade2。

Answer 2

可能会迟到但反应似乎在这里： http://developer.android.com/guide/topics/graphics/2d-graphics.html#frame-animation

Answer 3

最新文档似乎在这里：

http://developer.android.com/guide/topics/graphics/drawable-animation.html

如何做android图像动画

3 个答案: