我有一个带有页眉和页脚的UIcollectionView,有时候一个奇怪的错误只会显示屏幕为空。这很奇怪,因为即使在View Debugger上它显示为空,但是Header是一个静态图像,它在应用程序上并没有从API获得,也没有显示。
此外,控制台不提供任何错误方法。我尝试转到另一个视图并强制reloadData()但仍然没有显示任何内容。我可以用任何方式更好地调试它或确保它不会发生吗?
这是视图调试器的样子:
您可以看到页眉和页脚空可重复使用的视图:
修改
这是使用RxDataSources
创建补充视图的方式 dataSource.supplementaryViewFactory = { (dataSource, collectionView, kind, indexPath) in
switch kind {
case UICollectionElementKindSectionHeader:
let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: CellReuseId.contentHeaderCollectionView, for: indexPath ) as! ContentHeaderView
headerView.imageView.image = ImageAssets.contentBanner
let tapGestureRecognizer = UITapGestureRecognizer(target:self, action: #selector(self.showListOfEvents(_:)))
headerView.addGestureRecognizer(tapGestureRecognizer)
return headerView
case UICollectionElementKindSectionFooter:
let footerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: CellReuseId.contentFooterCollectionView, for: indexPath) as! ContentFooterView
footerView.setUpObjects()
//setUp Appropiate label or animation
let showFooter: Bool = !(self.centerActivityIndicator?.isAnimating ?? false)
footerView.setUpAppropiateDependingOnResults(isThereMoreResults: self.isThereMoreResults, showFooter: showFooter)
return footerView
default: break
}
//return default
return UICollectionReusableView()
}
这是获取API模型并将它们绑定到collectionView
的代码let results = Observable.of(paginationObserver, offlineObserver).merge()
//calls method that calls DB with the appropiate data
.flatMapLatest { [unowned self] parametersChanged -> Driver<LecturesStateResults> in
//since this is being called again, we make sure to clean out "old cache data" on view model
self.videoObject.lecturesResults.value.removeAll(keepingCapacity: true)
return self.setupLectures().asDriver(onErrorJustReturn: LecturesStateResults.empty)
}
results
//Bind the result observable to the UIcollectionView
//UiCollection view only wants an array not an Observable
.map {
if !$0.results.isEmpty { self.centerActivityIndicator?.stopAnimating()}
return [SectionModel(model: "", items: $0.results)]
}
.bind(to: lectureViewSquare.rx.items(dataSource: dataSource))
.addDisposableTo(disposeBag)
lectureViewSquare.rx.setDelegate(self)
.addDisposableTo(disposeBag)
答案 0 :(得分:1)
我在使用相同的ui渲染时遇到了同样的问题,但没有使用RxSwift。
解决问题的代码是
dispatch_async(dispatch_get_main_queue(), ^{
[self.collectionView reloadData];
});