[英]'UICollectionView must be initialized with a non-nil layout parameter' - Swift 4
[英]UiCollectionView must be initialized with a non-nil layout parameter Swift 3
我已經在StackOverflow上搜索了此問題的答案,並嘗試了不同的實現方法。 我有一個collectionView
,它具有一個按鈕,當按下該按鈕時,它會嘗試初始化另一個collectionView
。 這是堆棧跟蹤:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'UICollectionView must be initialized with a non-nil layout parameter'
*** First throw call stack:
(
0 CoreFoundation 0x000000010adb3d4b __exceptionPreprocess + 171
1 libobjc.A.dylib 0x00000001079b321e objc_exception_throw + 48
2 CoreFoundation 0x000000010ae1d2b5 +[NSException raise:format:] + 197
3 UIKit 0x0000000108eca775 -[UICollectionView initWithFrame:collectionViewLayout:] + 76
4 UIKit 0x0000000108f13abb -[UICollectionViewController _newCollectionViewWithFrame:collectionViewLayout:] + 108
5 UIKit 0x0000000108f12c94 -[UICollectionViewController loadView] + 678
6 UIKit 0x000000010873761c -[UIViewController loadViewIfRequired] + 201
7 UIKit 0x0000000108737e70 -[UIViewController view] + 27
8 UIKit 0x0000000108ff86a4 -[_UIFullscreenPresentationController _setPresentedViewController:] + 87
9 UIKit 0x0000000108712702 -[UIPresentationController initWithPresentedViewController:presentingViewController:] + 141
10 UIKit 0x000000010874ae97 -[UIViewController _presentViewController:withAnimationController:completion:] + 3956
11 UIKit 0x000000010874e26b -[UIViewController _performCoordinatedPresentOrDismiss:animated:] + 530
12 UIKit 0x000000010874dd51 -[UIViewController presentViewController:animated:completion:] + 179
13 TheAppProject 0x0000000107385842 _TFC17TheAppProject15DailyController12publishedTapfT6senderCSo8UIButton_T_ + 754
14 TheAppProject 0x00000001073859fa _TToFC17TheAppProject15DailyController12publishedTapfT6senderCSo8UIButton_T_ + 58
15 UIKit 0x00000001085978bc -[UIApplication sendAction:to:from:forEvent:] + 83
16 UIKit 0x000000010871dc38 -[UIControl sendAction:to:forEvent:] + 67
17 UIKit 0x000000010871df51 -[UIControl _sendActionsForEvents:withEvent:] + 444
18 UIKit 0x000000010871ce4d -[UIControl touchesEnded:withEvent:] + 668
19 UIKit 0x0000000108605545 -[UIWindow _sendTouchesForEvent:] + 2747
20 UIKit 0x0000000108606c33 -[UIWindow sendEvent:] + 4011
21 UIKit 0x00000001085b39ab -[UIApplication sendEvent:] + 371
22 UIKit 0x0000000108da072d __dispatchPreprocessedEventFromEventQueue + 3248
23 UIKit 0x0000000108d99463 __handleEventQueue + 4879
24 CoreFoundation 0x000000010ad58761 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
25 CoreFoundation 0x000000010ad3d98c __CFRunLoopDoSources0 + 556
26 CoreFoundation 0x000000010ad3ce76 __CFRunLoopRun + 918
27 CoreFoundation 0x000000010ad3c884 CFRunLoopRunSpecific + 420
28 GraphicsServices 0x000000010dc1ba6f GSEventRunModal + 161
29 UIKit 0x0000000108595c68 UIApplicationMain + 159
30 TheAppProject 0x0000000107366d8f main + 111
31 libdyld.dylib 0x000000010bd6368d start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
這是我的代碼:
private let reuseIdentifier = "cell"
class MyCollectionViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {
let myCell = MyCell()
override func viewDidLoad() {
super.viewDidLoad()
let layout = UICollectionViewFlowLayout()
let collectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
collectionView.backgroundColor = UIColor.black
collectionView.alwaysBounceVertical = true
collectionView.delegate = self
collectionView.dataSource = self
self.collectionView!.register(MyCell.self, forCellWithReuseIdentifier: reuseIdentifier)
}
// MARK: - Layout
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 325, height: 630)
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
return 60.0
}
}
您的MyCollectionViewController類是UICollectionViewController的子類,它具有collectionView的屬性,該屬性是實際的UICollectionView本身。 因此,您在此行中創建了單獨的UICollectionView:
let collectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
與UICollectionViewController本身提供的self.collectionView不同。
因此,這不是您得到的錯誤的根源。
實際上,您所看到的錯誤將中繼到您如何創建和呈現MyCollectionViewController本身。 您沒有顯示代碼的創建方式,但沒有向其傳遞任何布局。 例如,要在代碼中創建它,您可以這樣做:
let layout = UICollectionViewFlowLayout()
let myCollectionVC = MyCollectionViewController(collectionViewLayout: layout)
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