沿路径移动UIview

Question

我希望能够在按下手指时取出初始点，然后取出手指释放时的点，并获得两者之间的线（角度）并让球继续沿着该路径行进。我写了一些代码，但是当我尝试时，球似乎在所有不同的方向上都会出现。

for(Ball *balls in self.view.subviews){
        [UIView beginAnimations:nil context:nil];
        //[UIView setAnimationRepeatAutoreverses:NO];
        CGFloat x;
        CGFloat y;
        for(Ball *subBalls in self.view.subviews){
            if(balls != subBalls)
                if((CGRectIntersectsRect([balls frame], [subBalls frame]))){
                    [subBalls changeDirectionX];
                    [subBalls changeDirectionY];
                }
        }
        CGPoint point = balls.center;
        if(point.x + 25 > self.view.bounds.size.width)
            [balls changeDirectionX];
        if(point.x - 25 < 0)
            [balls changeDirectionX];
        if(point.y + 25 > self.view.bounds.size.height)
            [balls changeDirectionY];
        if(point.y - 25 < 0)
            [balls changeDirectionY];
        if(balls.directionX == 1){
            x = point.x + (balls.speed * cos(balls.addx));
        }
        else{
            x = point.x - (balls.speed * cos(balls.addx));
            //balls.addx;
        }
        if(balls.directionY == 1){
            y = point.y + (balls.speed * sin(balls.addx));
        }
        else
            y = point.y - (balls.speed * sin(balls.addx));
        //balls.addy;
        //CGFloat x = (CGFloat) random()/(CGFloat) RAND_MAX * self.view.bounds.size.width;
        //CGFloat y = (CGFloat) random()/(CGFloat) RAND_MAX * self.view.bounds.size.height;

        CGPoint squarePostion = CGPointMake(x, y);
        balls.center = squarePostion;

        [UIView commitAnimations];

这是我尝试计算角度的地方

-(void) dragging:(UIPanGestureRecognizer *)p{
    UIView *v = p.view;
    CGPoint velocity;
    if(p.state == UIGestureRecognizerStateBegan){
        self.origC = v.center;
        self.pointIn = [p locationInView:[UIApplication sharedApplication].keyWindow];
        //NSLog(@"%f",self.pointIn.x);
        //pointInWindow = CGPointMake(pointIn.x, pointIn.y);
    }
    //NSLog(@"%f,%f orig %f, %f",pointInWindow.x, pointInWindow.y,self.origC.x,self.origC.y);
    velocity = [p velocityInView:v.superview];
    //NSLog(@"x=%f",velocity.x);
    //NSLog(@"y=%f",velocity.y);
    [UIView animateWithDuration:1 delay:0 options:UIViewAnimationCurveEaseInOut animations:^{
        CGPoint delta = [p translationInView:v.superview];
        CGPoint c = self.origC;
        c.x += delta.x;
        c.y += delta.y;
        v.center = c;
    }completion:nil];
    if(p.state == UIGestureRecognizerStateEnded){
        CGPoint lastPoint = [p locationInView:[UIApplication sharedApplication].keyWindow];
        NSLog(@"lastpoint.x: %f, lastpoint.y: %f, pointin.x: %f, pointin.y%f",lastPoint.x,lastPoint.y,
              self.pointIn.x,self.pointIn.y);
        double velocityX = velocity.x;
        double velocityY = velocity.y;
        if(velocityX > velocityY)
            self.speed = velocityX/200;
        else
            self.speed = velocityY/200;
        //NSLog(@"orig %f , last %f",self.pointIn.x,lastPoint.x);
        self.lateC = v.center;
        CGFloat deltaX = lastPoint.x - self.pointIn.x;
        CGFloat deltaY = lastPoint.y - self.pointIn.y;;
        //NSLog(@"deltaX: %f, deltaY: %f ",deltaX,deltaY);
        double angle = atan(deltaY/deltaX) * 180/M_PI;
        if(angle < 0)
            angle += 360;
        NSLog(@"angle: %f",angle);
        self.addy = angle;
        self.addx = angle;
        self.timer = [NSTimer scheduledTimerWithTimeInterval:.5 target:self selector:@selector(changeVelocity) userInfo:nil repeats:YES];
    }
}

感谢您的帮助