ios - 向 UIPangesture 添加边界

Question

我在 subview 中有一个 UILabel 并且在 上有一个 panGesture 和 pinchGesture UILabel。截至目前，我可以将 UILabel 移动到所有 View 中。我希望此 UILabel 确实位于 subView 的区域内。我将如何做到这一点？

- (void)handlePanGesture:(UIPanGestureRecognizer *)panGesture {
CGPoint translation = [panGesture translationInView:panGesture.view.superview];

if (UIGestureRecognizerStateBegan == panGesture.state ||UIGestureRecognizerStateChanged == panGesture.state) {
    panGesture.view.center = CGPointMake(panGesture.view.center.x + translation.x,
                                         panGesture.view.center.y + translation.y);
    [panGesture setTranslation:CGPointZero inView:self.view];
 }
}

在这一行中，

CGPoint translation = [panGesture translationInView:panGesture.view.superview];

它正在将它设置为 superView，我试图将它设置为我的 subView，但我似乎无法弄明白。

Answer 1

这是我处理可拖动按钮并将其限制在主视图边界的代码希望这段代码能帮到你

 CGPoint translation = [recognizer translationInView:self.view];
    CGRect recognizerFrame = recognizer.view.frame;
    recognizerFrame.origin.x += translation.x;
    recognizerFrame.origin.y += translation.y;

    // Check if UIImageView is completely inside its superView
    if (CGRectContainsRect(self.view.bounds, recognizerFrame)) {
        recognizer.view.frame = recognizerFrame;
    }
    // Else check if UIImageView is vertically and/or horizontally outside of its
    // superView. If yes, then set UImageView's frame accordingly.
    // This is required so that when user pans rapidly then it provides smooth translation.
    else {
        // Check vertically
        if (recognizerFrame.origin.y < self.view.bounds.origin.y) {
            recognizerFrame.origin.y = 0;
        }
        else if (recognizerFrame.origin.y + recognizerFrame.size.height > self.view.bounds.size.height) {
            recognizerFrame.origin.y = self.view.bounds.size.height - recognizerFrame.size.height;
        }

        // Check horizantally
        if (recognizerFrame.origin.x < self.view.bounds.origin.x) {
            recognizerFrame.origin.x = 0;
        }
        else if (recognizerFrame.origin.x + recognizerFrame.size.width > self.view.bounds.size.width) {
            recognizerFrame.origin.x = self.view.bounds.size.width - recognizerFrame.size.width;
        }
    }

    // Reset translation so that on next pan recognition
    // we get correct translation value
    [recognizer setTranslation:CGPointZero inView:self.view];