在 android 中基于 onTouchListener 旋转包含贴纸的布局

Question

我已经尝试了一个多星期了，但我无法根据触摸正确旋转布局（相对）。我需要设置旋转角度，以便当我在布局的左下角（有一个小图像）移动手指时布局旋转。基本上我有一个带有贴纸图像的相对布局。我可以通过触摸布局的相应角来拖动和缩放贴纸（图片），但我无法正确旋转它。谁能帮我设置一下旋转角度，这样整个布局就可以顺畅旋转了？

这是代码片段

            switch (event.getAction()) {

            case MotionEvent.ACTION_DOWN: {
                lastTouchedScaleXPosition = event.getX();
                lastTouchedScaleYPosition = event.getY();

                if(previousXPosition == 0 && previousYPosition == 0){

                    int[] viewLocation = new int[2];
                    v.getLocationOnScreen(viewLocation);
                    previousXPosition= viewLocation[0];
                    previousYPosition= viewLocation[1];

                }
                break;
            }

            case MotionEvent.ACTION_MOVE: {

                currentTouchedXPosition = event.getX() - lastTouchedScaleXPosition;
                currentTouchedYPosition = event.getY() - lastTouchedScaleYPosition;

                currentXPosition = previousXPosition + currentTouchedXPosition;
                currentYPosition = previousYPosition + currentTouchedYPosition;


                RelativeLayout mainLayout = (RelativeLayout) findViewById(R.id.parent);
                int w =  mainLayout.getWidth();
                int h =  mainLayout.getHeight();

                float center_x = 0;
                float center_y = 0;
                center_x +=  w/2;
                center_y +=  h/2;

                double tx = currentXPosition - center_x, ty = currentYPosition - center_y;
                double t_length = Math.sqrt(tx*tx + ty*ty);
                double a = Math.toDegrees(Math.acos(ty / t_length));

                mainLayout.setRotation((float) a);

                mainLayout.setTranslationX((w - h) / 2);
                mainLayout.setTranslationY((h - w) / 2);

                ViewGroup.LayoutParams lp = (ViewGroup.LayoutParams) mainLayout.getLayoutParams();
                lp.height = w;
                lp.width =  h;

                parent.setLayoutParams(lp);


                previousXPosition = currentXPosition;
                previousYPosition = currentYPosition;

                break;
            }
        }
        return true;
    }

`

Answer 1

尝试了很多但没有得到想要的 result.This link 帮我解决了这个问题。 rotate and resize the image view with single finger in android

来源linkhttps://github.com/ryanch741/android-view-rotate-zoom-single-finger

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