iphone - 如何限制平移手势区域？

Question

我有我的 UIImageView 我有另一个 UIView 矩形。通过对 UIView 矩形应用平移手势，它也可以在 UIImageView 之外。我不想被拖到 UIImageView

之外

我试过下面的代码，但它不是这样工作的

-(void)handleMovementView:(UIPanGestureRecognizer *)recognizer
{
    CGPoint movement;

    if(recognizer.state == UIGestureRecognizerStateBegan || recognizer.state == UIGestureRecognizerStateChanged || recognizer.state == UIGestureRecognizerStateEnded)
    {
        CGRect rec = recognizer.view.frame;
        CGRect imgvw = self.imgViewCrop.frame;
        if((rec.origin.x >= imgvw.origin.x && (rec.origin.x + rec.size.width <= imgvw.origin.x + imgvw.size.width)))
        {
            CGPoint translation = [recognizer translationInView:recognizer.view.superview];
            movement = translation;
            recognizer.view.center = CGPointMake(recognizer.view.center.x + translation.x, recognizer.view.center.y + translation.y);
            [recognizer setTranslation:CGPointZero inView:recognizer.view.superview];
            [self handleMovementForHandlers:movement];
        }
    }

}

如果我缓慢地应用 Pan 它会应用这个条件但是当我快速地应用它时它会超出 ImageView

Answer 1

不是手动计算点是否在 View 的边界内，而是使用 CGRectContainsPoint(rect, point)。这对我有用，我喜欢它，因为它更短且更易读:

func handlePan(pan: UIPanGestureRecognizer) {
    switch pan.state {
    case .Began:
        if CGRectContainsPoint(self.pannableView.frame, pan.locationInView(self.pannableView)) {
            // Gesture started inside the pannable view. Do your thing.
        }
}