我知道标题有点混乱，所以我会尽力解释清楚。我有一个固定宽度为 100 的 UIView 和一个从 0 开始的可变高度。我想要做的是将我的手指从 UIView 的底部拖到屏幕顶部，然后将 UIView改变它的高度/延伸到我手指的位置。如果这仍然很复杂，那就把它想象成从某物下面拉出一条纸条。
如果您能提供帮助，那就太好了。我觉得应该不会太难，但我只是初学者，如果我没有解释清楚，我可以理解！
【问题讨论】：
标签： ios objective-c uiview
这应该是直截了当的UIPanGestureRecognizer 和一点数学。要将视图更改为正确的框架（我使用名称 _viewToChange，因此稍后将其替换为您的视图），只需添加：
UIPanGestureRecognizer * pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(pan:)];
pan.maximumNumberOfTouches = pan.minimumNumberOfTouches = 1;
[self addGestureRecognizer:pan];
到你的init方法为超级视图，并定义方法：
- (void)pan:(UIPanGestureRecognizer *)aPan; {
CGPoint currentPoint = [aPan locationInView:self];
[UIView animateWithDuration:0.01f
animations:^{
CGRect oldFrame = _viewToChange.frame;
_viewToChange.frame = CGRectMake(oldFrame.origin.x, currentPoint.y, oldFrame.size.width, ([UIScreen mainScreen].bounds.size.height - currentPoint.y));
}];
}
当用户手指移动时，这应该会为视图设置动画。希望有帮助！
【讨论】：
currentPoint.y。确保currentPoint.y 在某个区间内（使用MAX 和MIN 函数）将为您提供所需的结果。至于你想要它选择的视图，只需查看currentPoint.x，并弄清楚它在哪里。如果它在左侧（小于屏幕宽度的 1/3），则使用第一个视图。如果它在中间，则使用第二个视图等。
CGPoint velocity = [gestureRecognizer velocityInView:yourView];，您应该能够确定它正在朝哪个方向移动。
使用从 Storyboard 添加到 UIView 的 PanGesture 并将委托设置为 self。 UIView 附加到屏幕底部。
class ViewController: UIViewController {
var translation: CGPoint!
var startPosition: CGPoint! //Start position for the gesture transition
var originalHeight: CGFloat = 0 // Initial Height for the UIView
var difference: CGFloat!
override func viewDidLoad() {
super.viewDidLoad()
originalHeight = dragView.frame.height
}
@IBOutlet weak var dragView: UIView! // UIView with UIPanGestureRecognizer
@IBOutlet var gestureRecognizer: UIPanGestureRecognizer!
@IBAction func viewDidDragged(_ sender: UIPanGestureRecognizer) {
if sender.state == .began {
startPosition = gestureRecognizer.location(in: dragView) // the postion at which PanGestue Started
}
if sender.state == .began || sender.state == .changed {
translation = sender.translation(in: self.view)
sender.setTranslation(CGPoint(x: 0.0, y: 0.0), in: self.view)
let endPosition = sender.location(in: dragView) // the posiion at which PanGesture Ended
difference = endPosition.y - startPosition.y
var newFrame = dragView.frame
newFrame.origin.x = dragView.frame.origin.x
newFrame.origin.y = dragView.frame.origin.y + difference //Gesture Moving Upward will produce a negative value for difference
newFrame.size.width = dragView.frame.size.width
newFrame.size.height = dragView.frame.size.height - difference //Gesture Moving Upward will produce a negative value for difference
dragView.frame = newFrame
}
if sender.state == .ended || sender.state == .cancelled {
//Do Something
}
}
}
【讨论】：
这是我的快速解决方案，使用自动布局和要调整大小的视图的高度限制，同时根据安全区域设置上限和下限
private var startPosition: CGPoint!
private var originalHeight: CGFloat = 0
override func viewDidLoad() {
super.viewDidLoad()
let panGesture = UIPanGestureRecognizer(target: self, action: #selector(viewDidDrag(_:)))
resizableView.addGestureRecognizer(panGesture)
}
@objc private func viewDidDrag(_ sender: UIPanGestureRecognizer) {
if sender.state == .began {
startPosition = sender.location(in: self.view)
originalHeight = detailsContainerViewHeight.constant
}
if sender.state == .changed {
let endPosition = sender.location(in: self.view)
let difference = endPosition.y - startPosition.y
var newHeight = originalHeight - difference
if view.bounds.height - newHeight < topSafeArea + backButtonSafeArea {
newHeight = view.bounds.height - topSafeArea - backButtonSafeArea
} else if newHeight < routeDetailsHeaderView.bounds.height + bottomSafeArea {
newHeight = routeDetailsHeaderView.bounds.height
}
resizableView.constant = newHeight
}
if sender.state == .ended || sender.state == .cancelled {
//Do Something if interested when dragging ended.
}
}
【讨论】：