在我的UICollecitonView中,我使用
self.DataTableCollectionView.reloadData()
但是随着我收集的数据越来越多,它的滚动变得粗糙,在加载一些页面后,它变得很难向上或向下滚动。它被卡住了。
最终,当我尝试一次加载1000行时,滚动工作顺利,但当我尝试使用API一次分页和加载50行时,滚动变得很难。
有什么问题吗?谁能帮我解决一下?
我不知道是什么问题?self.DataTableCollectionView.reloadData()是这个问题的原因吗?
下面是在滚动时加载数据的代码:
func scrollViewDidScroll(scrollView: UIScrollView) {
let offsetY = scrollView.contentOffset.y
let contentHeight = scrollView.contentSize.height
if(offsetY > (contentHeight - scrollView.frame.size.height)){
let seconds = 3.0
let delay = seconds * Double(NSEC_PER_SEC)
let dispatchTime = dispatch_time(DISPATCH_TIME_NOW, Int64(delay))
self.loadMoreData()
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), {
self.DataTableCollectionView.reloadData()
})
}
}
==========
我把这些细胞
self.DataTableCollectionView .registerNib(UINib(nibName: "DCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: dCellIdentifier)
self.DataTableCollectionView .registerNib(UINib(nibName: "CCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: cCellIdentifier)
并重复使用:
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
let dCell : DCollectionViewCell = collectionView .dequeueReusableCellWithReuseIdentifier(dCellIdentifier, forIndexPath: indexPath) as! DCollectionViewCell
let cCell : ContentCollectionViewCell = collectionView .dequeueReusableCellWithReuseIdentifier(cCellIdentifier, forIndexPath: indexPath) as! CCollectionViewCell
}
=========
添加更具体的代码:
现在我更新了我的滚动功能,
func scrollViewDidScroll(scrollView: UIScrollView) {
let offsetY = scrollView.contentOffset.y
let contentHeight = scrollView.contentSize.height
if(offsetY > (contentHeight - scrollView.frame.size.height)){
var returnTableData = NSMutableArray()
self.InspectPageId = self.InspectPageId+1
self.dataSource.populateData(PageId:self.InspectPageId)
returnTableData = self.dataSource.DTableDataArray
if(returnTableData.count>0){
for i in 0..<returnTableData.count {
self.TableDataArray.addObject(returnTableData[i])
}
}
self.NumberOfRows = self.TableDataArray.count
dispatch_async(dispatch_get_main_queue(),{
self.DataTableCollectionView.reloadData()
})
}
}
以下是手动创建集合视图的代码:
if indexPath.row == 0 {
//Here Header Cell is creating
let dateCell : DateCollectionViewCell = collectionView .dequeueReusableCellWithReuseIdentifier(dateCellIdentifier, forIndexPath: indexPath) as! DateCollectionViewCell
dateCell.dateLabel.font = UIFont(name:"HelveticaNeue", size: 12)
dateCell.dateLabel.textColor = UIColor.blackColor()
dateCell.dateLabel.textAlignment = .Left
dateCell.dateLabel.text = UMIDDataArray[rowIndex-1] as? String
dateCell.backgroundColor = UIColor.whiteColor()
dateCell.layer.shouldRasterize = true
dateCell.layer.rasterizationScale = UIScreen.mainScreen().scale
return dateCell
} else {
//Here Data Cell is Creating
let contentCell : ContentCollectionViewCell = collectionView .dequeueReusableCellWithReuseIdentifier(contentCellIdentifier, forIndexPath: indexPath) as! ContentCollectionViewCell
contentCell.contentLabel.font = UIFont(name:"HelveticaNeue", size: 12)
contentCell.contentLabel.textColor = UIColor.blackColor()
contentCell.contentLabel.textAlignment = .Left
contentCell.bottomBorder.hidden = false
contentCell.layer.shouldRasterize = true
contentCell.layer.rasterizationScale = UIScreen.mainScreen().scale
let LensData:NSArray = TableDataArray[rowIndex-1] as! NSArray
let ColumnValue = LensData[colIndex-1] as? String
contentCell.contentLabel.text = ColumnValue
contentCell.backgroundColor = UIColor.whiteColor()
return contentCell
}
Following is the code which is use to take data from API:
//function of DataSource Class.
func populateData(PageId:Int){
var returnData = NSMutableArray()
let OtherColobjects = NSMutableArray()
let Urlpath = SetApiUrl()
let url: NSURL = NSURL(string: Urlpath)!
let urlRequest = NSURLRequest(URL: url)
let config = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: config)
let semaphore = dispatch_semaphore_create(0)
let task = session.dataTaskWithRequest(urlRequest) {
(data, response, error) in
guard error == nil else {
return
}
guard let responseData = data else {
return
}
do {
guard let Data = try NSJSONSerialization.JSONObjectWithData(responseData, options: []) as? [String: AnyObject] else {
return
}
for anItem in Data["result"]!["DATA"] as! [Dictionary<String, AnyObject>] {
let d1 = self.checkForNull(anItem["data1"]!)
let d2 = self.checkForNull(anItem["data2"]!)
let d3 = self.checkForNull(anItem["data3"]!)
let d4 = self.checkForNull(anItem["data4"]!)
...... // Total 20 Columns
let obj = [ d1, d2, d3, d4,.............,d20 ]
OtherColobjects.addObject(obj)
}
dispatch_semaphore_signal(semaphore)
} catch {
return
}
}
task.resume()
dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER)
self.NumberOfRows = returnData[0].count
self.DTableDataArray = returnData[1] as! NSMutableArray
}
7条答案
按热度按时间vsdwdz231#
在出队单元格后添加以下2行,
wj8zmpe12#
你应该只从主线程更新你的UI,所以这样做代替...
Swift 2.x:
如果这不能解决问题,那么你可能还需要在后台线程上调用
loadMoreData()
。Swift 2.x:
由于您没有向我们展示您的
loadMoreData()
函数,因此不清楚您的代码是如何工作的。实际上,您可能想从loadMoreData
内部调用DataTableCollectionView.reloadData()
,但我无法在没有看到函数的情况下判断。请添加额外的代码hm2xizp93#
你应该在
MainThread
上调度reloadData()
。根据苹果文档,操作UI应该总是在MainThread
中完成。bvk5enib4#
如果
self.loadMoreData()
不是异步的,它会阻塞你的UI。self.DataTableCollectionView.reloadData()
应该在主线程上从self.loadMoreData()
调用。即使这不是阻塞,你也会在每个页面上多次调用
loadMoreData()
。你应该添加一个布尔值来检查你是否已经加载了数据,让我们称之为isLoading
。当你初始化viewcontroller时,将isLoading
设置为false。在self.loadMoreData()
中将其设置为true,并在scrollViewDidScroll(scrollView: UIScrollView)
中更改check,因此它看起来像这样:gev0vcfq5#
在主队列中重新加载搭配
fjaof16o6#
尝试将您的reload collectionview从scrollviewdidscroll移动到loadmoredata()
public void run(){
/* 1.列出项目2.然后在最后调用realoadata 3.如果单元格中有图像,则使用图像缓存,可以编程图像缓存或使用SDWebImage等库 */
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0),{self.DataTableCollectionView.reloadData()})
}
unhi4e5o7#
重新加载数据前禁用动画
对我很有效。