android旋转图像

Question

我正在尝试创建两个旋转的轮子，就像滑轮一样，所以每次连接的绳子移动时，两个滑轮都会旋转。我尝试了两种方法：

1)在View类的onDraw()方法中使用Matrix.postRotate，该方法调用以下内容：

private void drawSpinningWheel(Canvas canvas)
{
    try
    {
        canvas.save();

            Bitmap bitmapOrg = null;

        int iDrawable = R.drawable.spinning_button;

        bitmapOrg = BitmapFactory.decodeResource(getResources(), iDrawable);

        if(bitmapOrg != null)
        {
            int width = bitmapOrg.getWidth(); 
            int height = bitmapOrg.getHeight(); 
            int newWidth = 24; 
            int newHeight = 24; 

            // calculate the scale - in this case = 0.4f 
            float scaleWidth = ((float) newWidth) / width; 
            float scaleHeight = ((float) newHeight) / height; 

            // createa matrix for the manipulation 
            Matrix matrix = new Matrix(); 
            // resize the bit map 
            matrix.postScale(scaleWidth, scaleHeight); 
            matrix.postRotate((float) mDegrees++);

            Bitmap resizedBitmap = Bitmap.createBitmap(bitmapOrg, 0, 0, 
                    width, height, matrix, true); 

            canvas.drawBitmap(resizedBitmap, matrix, null);

        }

        canvas.restore();
    }
    catch(Exception e)
    {
        Log.e(TAG + "drawSpinningWheel", e.getMessage());
    }

}

但是看起来图像不仅旋转，而且绕着另一个轴旋转。

2)使用SurfaceView和一个单独的线程，在run()调用：

    private void doDraw(Canvas canvas) {
        // Draw the background image. Operations on the Canvas accumulate
        // so this is like clearing the screen.
        canvas.drawBitmap(mBackgroundImage, 0, 0, null);

        int yTop = mCanvasHeight - ((int) mY + mSpinningWheelImageHeight / 2);
        int xLeft = (int) mX - mSpinningWheelImageWidth / 2;

..。

        // Draw the ship with its current rotation
        canvas.save();
        canvas.rotate((float) mHeading++, (float) mX, mCanvasHeight
                - (float) mY);

            mSpinningWheelImage.setBounds(xLeft, yTop, xLeft + mSpinningWheelImageWidth, yTop
                    + mSpinningWheelImageHeight);
            mSpinningWheelImage.draw(canvas);


        canvas.restore();
    }

我得到了旋转工作，但我不能添加另一个旋转轮子。我甚至尝试为第二个旋转轮创建另一个线程，但只显示了一个线程。谁能给我指个方向？谢谢。

3)好了，现在我也尝试了RotateAnimation：

公共类GraphicsView扩展了视图{私有静态最终字符串QUOTE =“没有人再使用Java了。这是一个很大的重量级球和链子。”；

private Animation anim;
private Animation anim2;

private Bitmap jobs;
private Bitmap wheel;

private int jobsXOffset;        
private int jobsYOffset;

private int wheelXOffset;        
private int wheelYOffset;

public GraphicsView(Context context) 
{
    super(context);
    jobs = BitmapFactory
    .decodeResource(getResources(), R.drawable.spinning_button);

    jobsXOffset = jobs.getWidth() / 2;
    jobsYOffset = jobs.getHeight() / 2;

    wheel = BitmapFactory
    .decodeResource(getResources(), R.drawable.wheel);

    wheelXOffset = jobs.getWidth() / 2;
    wheelYOffset = jobs.getHeight() / 2;


}

private void createAnim(Canvas canvas) 
{
    anim = new RotateAnimation(0, 360, canvas.getWidth() / 2, canvas
            .getHeight() / 2);
    anim.setRepeatMode(Animation.INFINITE);
    anim.setRepeatCount(Animation.INFINITE);
    anim.setDuration(10000L);
    anim.setInterpolator(new AccelerateDecelerateInterpolator());

    startAnimation(anim);
}

private void createAnim2(Canvas canvas) 
{
    anim2 = new RotateAnimation(0, 360, canvas.getWidth() / 2+30, canvas
            .getHeight() / 2);
    anim2.setRepeatMode(Animation.INFINITE);
    anim2.setRepeatCount(Animation.INFINITE);
    anim2.setDuration(10000L);
    anim2.setInterpolator(new AccelerateDecelerateInterpolator());

    startAnimation(anim);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);

    // creates the animation the first time
    if (anim == null) {
        createAnim(canvas);
    }

    int centerX = canvas.getWidth() / 2;
    int centerY = canvas.getHeight() / 2;

    canvas.drawBitmap(jobs, centerX - jobsXOffset,
            centerY - jobsYOffset, null);

    canvas.drawBitmap(wheel, centerX - wheelXOffset + 30,
            centerY - wheelYOffset, null);

}

}

但结果类似于Canvas.Rotate，我能够让第一张图像旋转得很好，但第二张图像将简单地围绕第一张图像旋转，尽管我注意到第二张图像实际上也在旋转。看起来我需要一个单独的视图来查看第二张图片，我希望避免这种情况，因为我不确定如何让轮子旋转，但连接的绳子不旋转。

Answer 1

你试过RotateAnimation吗？

Answer 2

看看我的问题和答案，我想这就是你(和我)正在寻找的……How to spin an android icon on its center point?

我放了三个动画，我的标志文本和我的标志图标。然后，我对文本进行负旋转，对图标进行正旋转。这很简单，但很酷。我的问题的答案是代码清单。