机器人旋转图像

Question

我正在尝试创建两个纺车，就像在滑轮中一样，因此每次连接的绳索移动时，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，它调用以下内容:

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());
    }

}

但看起来图像不仅旋转而且还绕着另一个轴旋转

2) 使用 SurfaceView 和一个单独的线程，在 run() 中调用:

    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();
    }

我可以让纺车工作，但我无法添加另一个纺车。我什至试图为第二个纺车创建另一个线程，只有一个出现。有人能指出我正确的方向吗？谢谢。

3) 好的，现在我也尝试了 RotateAnimation:

公共(public)类 GraphicsView 扩展 View { 私有(private)静态最终字符串引用 = “没有人再使用 Java。这是一个重量级的大链条。”;

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，我能够让第一张图片旋转得很好，但第二张图片只会围绕第一张图片旋转，尽管我注意到第二张图片实际上也在旋转。看起来我需要一个单独的 View 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会旋转。

Answer 1

你试过RotateAnimation了吗？