向 UIPangesture 添加边界
Add boundaries to a UIPangesture
我在 subview
中有一个 UILabel
,在 UILabel
中有一个 panGesture
和 pinchGesture
。截至目前,我可以移动 UILabel
穿过所有视图。我希望这个 UILabel
留在 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,我正在尝试将它设置为我的 subView,但我似乎无法弄明白。
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];
我在 subview
中有一个 UILabel
,在 UILabel
中有一个 panGesture
和 pinchGesture
。截至目前,我可以移动 UILabel
穿过所有视图。我希望这个 UILabel
留在 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,我正在尝试将它设置为我的 subView,但我似乎无法弄明白。
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];