在Android的2手指旋转手势监听器 [英] 2 Finger Rotation gesture listener in android

问题描述

我试图找出使图像旋转，随着用户的手指拖动它向左或向右的最佳方式，而旋转的角度。

 浮动X1 = lastEvent [0]  -  lastEvent [1];
浮Y1 = lastEvent [2]  -  lastEvent [3];
浮动degrees1 =（浮点）（Math.atan2（Y1，X1））;
浮χ2= event.getX（0） -  event.getX（1）;
浮Y2 = event.getY（0） -  event.getY（1）;
浮动degrees2 =（浮点）（Math.atan2（Y2，X2））;浮度=（浮点）Math.toDegrees（degrees2-degrees1）;
 

不过，这并不像旋转，我想它..是否有旋转手势的监听器？谢谢

解决方案

  / **确定前两个手指之间的度* /
    私人浮动旋转（MotionEvent事件）{
        双delta_x =（event.getX（0） -  event.getX（1））;
        双delta_y =（event.getY（0） -  event.getY（1））;
        双弧度= Math.atan2（delta_y，delta_x）;
        如果（Constant.TRACE）Log.d（旋转~~~~~~~~~~~~~~~~~，delta_x +##+ delta_y +##+弧度+##
                        + Math.toDegrees（弧度））;
        回报（浮）Math.toDegrees（弧度）;
    }
 

I'm trying to figure out the best way to make an image rotate along with a user's finger dragging it left or right, and the angle of rotation.

float x1 = lastEvent[0] - lastEvent[1];
float y1 = lastEvent[2] - lastEvent[3];    
float degrees1 = (float)(Math.atan2(y1, x1));      
float x2 = event.getX(0) - event.getX(1);
float y2 = event.getY(0) - event.getY(1);
float degrees2 = (float)(Math.atan2(y2, x2));   

float degrees = (float) Math.toDegrees(degrees2-degrees1);

But it doesn't rotate like i want it.. Is there any listener for rotation gesture? Thanks

解决方案

/** Determine the degree between the first two fingers */
    private float rotation(MotionEvent event) { 
        double delta_x = (event.getX(0) - event.getX(1));
        double delta_y = (event.getY(0) - event.getY(1));
        double radians = Math.atan2(delta_y, delta_x);       
        if (Constant.TRACE) Log.d("Rotation ~~~~~~~~~~~~~~~~~", delta_x+" ## "+delta_y+" ## "+radians+" ## "
                        +Math.toDegrees(radians));
        return (float) Math.toDegrees(radians);
    }

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