How to drag up UIContainer view in parent UIView within certain limits? - ios

Question

How would you go about dragging up a tab at the bottom of the screen like in apple maps and be able to drag it above the parent UIView, but keep it constrained within bounds of the screen.
i got this code which I'm trying to modify for my use case but I'm struggling to set the right bounds so it cant move up past a certain point and move down past a certain point.
var originalX: CGFloat = 0.0
var originalY: CGFloat = 0.0
#objc func handlePanGesture(gesture: UIPanGestureRecognizer) {
guard let panView = gesture.view else {
return
}
self.view.bringSubviewToFront(panView)
var translatedPoint = gesture.translation(in: self.view)
if gesture.state == .began {
originalX = panView.center.x
originalY = panView.center.y
}
translatedPoint = CGPoint(x: originalX, y: originalY + translatedPoint.y)
print(originalY + translatedPoint.y)
print(view.frame.height)
if (originalY + translatedPoint.y) > view.frame.height {
UIView.animate(withDuration: 0.1, delay: 0, options: [.curveEaseInOut], animations: {
gesture.view?.center = translatedPoint
} , completion: nil)
}
}
new code with offset
var originalX: CGFloat = 0.0
var originalY: CGFloat = 0.0
var currentPoint: CGPoint?
var position:CGPoint?
#objc func handlePanGesture(gesture: UIPanGestureRecognizer) {
guard let panView = gesture.view else {
return
}
self.view.bringSubviewToFront(panView)
var translatedPoint = gesture.translation(in: self.view)
if gesture.state == .began {
originalX = panView.center.x
originalY = panView.center.y
}
translatedPoint = CGPoint(x: originalX, y: originalY + translatedPoint.y)
//if offsetY >= 9 {
UIView.animate(withDuration: 0.1, delay: 0, options: [.curveEaseInOut], animations: {
gesture.view?.center = translatedPoint
} , completion: nil)
//}
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first {
position = touch.location(in: view)
//print("position\(position)")
}
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
if let touch = touches.first {
currentPoint = touch.location(in: view)
//print("currentPoint\(currentPoint)")
let offsetY = currentPoint!.y - position!.y
print(offsetY)
}
}
out put when dragging container view
2.0
0.5
9.0
1.0
8.0
0.5
4.0
7.5
-0.5
-6.5
-1.0
-8.0
output for dragging on uiview
-11.5
-21.5
-36.0
-52.0
-74.5
-86.5
-98.0
-102.0
-106.0
-112.0
-116.5
-120.0
-122.5
-124.0
-124.0
-124.0
-124.0
-124.0
-123.5
-120.5
-116.5
-114.0
-109.0
-104.5
-97.0
-89.0
-80.0
-74.0
-66.0
-58.5
-54.5
-49.5
-47.0
-42.5
-39.5
-35.5
-31.0
-28.5
-24.0
-21.5
-19.5
-18.0
-16.0
-15.5
-15.0

Answer 1

You can try that, and record the TouchPoint at TouchBegin（beginDrag） and get currentPoint at TouchMove（dragging）——I don't remember the specific agency method. By calculating offsetX = currentpoint.x - touchpoint.x. Using gestures to calculate is too complicated。
offsetX = currentpoint.x - touchpoint.x;
offsetY = currentpoint.y - touchpoint.y;