我正在开发一个应用程序，用户可以在其中滑动“卡”，这些卡基本上是用API数据填充的UIViews。
首次打开应用程序时，将创建卡片并将其作为子视图添加到超级视图。每次用户滑动时，都会从超级视图中移除该卡片。
当用户刷卡时，将创建更多卡并将其缓存在后台。
当用户位于最后一张卡片上时，我将缓存的卡片添加到当前显示的卡片后面的Superview中。
问题是在将卡片添加到超级视图时，我的手势识别器停止工作/出现故障（用户无法滑动）。几秒钟后，它再次开始工作，用户可以滑动。
如何阻止识别器出现故障？任何见识将不胜感激。
谢谢！
这是创建/添加卡的代码
//创建卡片
func createCards（firstCall：Bool）{
APICall.begin () { (info) in
DispatchQueue.main.async {
for i in info {
let frontView = frontView()
let backView = backView()
// Set up front and back views
self.viewSetup(view: frontView)
self.viewSetup(view: backView)
// Set up card view
let view = cardView(frame: frame)
view.addSubview(backView)
view.addSubview(frontView)
self.viewSetup(view: view)
view.isHidden = true
// function that add recognizer
self.dragging(view: view)
// cacheCard
if !firstCall{
self.cache.add(cardView: view)
// add to view
}else{
self.view.addSubview(view)
}
}
// Reveal current card
if firstCall {
self.view.subviews.last?.isHidden = false
}
print("DONE")
}
}
}
这是添加识别器/添加缓存的代码
// dragging gesture helper
func draggig(card: view){
let gesture = UIPanGestureRecognizer(target: self, action: #selector(ViewController.wasDragged(_:)))
view.addGestureRecognizer(gesture)
view.isUserInteractionEnabled = true
}
// dragged gestrues
func wasDragged(_ gesture: UIPanGestureRecognizer){
// Only allow dragging when front is showing
if(showingFront){
// Dragging code
let helper = draggingBeganHelper(gesture: gesture)
let card:UIView = helper[0] as! UIView
var rotation:CGAffineTransform = helper[1] as! CGAffineTransform
var stretch:CGAffineTransform = helper.last as! CGAffineTransform
if gesture.state == UIGestureRecognizerState.ended {
rotation = CGAffineTransform(rotationAngle: 0)
stretch = rotation.scaledBy(x: 1, y: 1)
//Remove card from superview
card.removeFromSuperview()
// Store cards in cache
if(self.view.subviews.count == lastCardIndex + cardOffset){
createCards(false)
}
// When at the second to last card
else if self.view.subviews.count == lastCardIndex+1{
if cardCacheArray.isEmpty {
createCards(true)
}
else{
DispatchQueue.main.async {
for i in cardCacheArray{
self.view.insertSubview(i, belowSubview: self.view.subviews[lastCardIndex])
}
self.cache.empty()
}
}
}
}
}
}
func draggingBeganHelper(gesture: UIPanGestureRecognizer) -> [AnyObject]{
// Card dragging gesture setup
let translation = gesture.translation(in: self.view)
let card = gesture.view
card?.center = CGPoint(x: (card?.center.x)! + translation.x, y: (card?.center.y)! + translation.y)
let xFromCenter = (card?.center.x)! - self.view.bounds.width/2
let scale = min(100/abs(xFromCenter),1)
let rotation = CGAffineTransform(rotationAngle: xFromCenter/200)
let stretch = rotation.scaledBy(x: scale, y: scale)
card?.transform = stretch
return [card!,rotation as AnyObject,stretch as AnyObject]
}
最佳答案
弄清楚了。一次加载太多的UIView。更好，更流畅的方法是不断回收两个UIViews
关于ios - 使用手势识别器添加 subview 时遇到UI故障，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/40943712/