圆形视图上的 UIGestureRecognizer

Question

我有一个 UIView，我使用下面的代码使它变圆。

[myView setBackgroundColor:[UIColor redColor]];
[[myView layer] setCornerRadius:[myView bounds].size.height / 2.0f];
[[myView layer] setMasksToBounds:YES];
[myView setClipsToBounds:YES];

然后添加UIPanGestureRecognizer移动方块

UIPanGestureRecognizer *panGesture=[[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(boxIsMoving:)];
        [myView addGestureRecognizer:panGesture];

但问题是，当用户点击圆外但在实际框架中并开始拖动时，我的视图也开始移动。谁能建议我如何忽略回合外的触球。

Answer 1

您可以使用此委托方法。如果触摸在拐角半径之外，它将 return 否。

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
    CGPoint  touchPoint = [touch locationInView:myView];
    if (CGRectContainsPoint(myview.bounds, touchPoint))
    {
        CGFloat centerX = CGRectGetMidX(myView.bounds);
        CGFloat centerY = CGRectGetMidY(myView.bounds);
        CGFloat radius2 = pow((touchPoint.x -centerX),2)+ pow((touchPoint.y - centerY), 2);
        if (radius2 < pow(CGRectGetWidth(myView.frame)/2, 2))
        {
            return YES;
        }
    }
    return NO;
}

Answer 2

正如 Erik Dolor 所建议的那样，您可以只计算手势与视图中心点之间的距离。使用这样的东西；

- (IBAction)boxIsMoving:(UIPanGestureRecognizer *)gestureRecognizer
{
    CGPoint viewCentre = CGPointMake(myView.bounds.size.width / 2, myView.bounds.size.height / 2);

    CGPoint gesturePosition = [gestureRecognizer locationInView:self.view];

    float distanceGestureToViewCentre = abs((sqrt((viewCentre.x - gesturePosition.x) 
                                             * (viewCentre.x - gesturePosition.x)
                                             + (viewCentre.y - gesturePosition.y) 
                                             * (viewCentre.y - gesturePosition.y))));

    if(distanceTapToViewCentre < radiusOfView)
    {
        // Handle pan
    }
    else
    {
        // Do nothing
    }
}

圆形视图上的 UIGestureRecognizer

UIGestureRecognizer on a rounded view

ios

objective-c

uigesturerecognizer

rounded-corners

uipangesturerecognizer