我在我的应用程序中已经有大约5个UIScrollView，它们都加载了多个.xib文件。我们现在想要使用UIRefreshControl。它们构建为与UITableViewControllers一起使用（根据UIRefreshControl类引用）。我不想重新做所有5个UIScrollView的工作。我已经尝试在我的UIRefreshControl中使用UIScrollView，除了一些东西之外它按预期工作。
UIScrollView跳下大约10个像素，这只有在我非常小心地将UIScrollview拖得很慢时才会发生。UIScrollView，UIScrollView停留在我放手的地方。重新加载完成后，UIScrollView跳到顶部没有动画。这是我的代码：
-(void)viewDidLoad
{
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
[refreshControl addTarget:self action:@selector(handleRefresh:) forControlEvents:UIControlEventValueChanged];
[myScrollView addSubview:refreshControl];
}
-(void)handleRefresh:(UIRefreshControl *)refresh {
// Reload my data
[refresh endRefreshing];
}
有什么方法可以节省一大堆时间并在UIRefreshControl中使用UIScrollView？
谢谢！！！
我有一个UIRefreshControl与UIScrollView一起工作：
- (void)viewDidLoad
{
UIScrollView *scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)];
scrollView.userInteractionEnabled = TRUE;
scrollView.scrollEnabled = TRUE;
scrollView.backgroundColor = [UIColor whiteColor];
scrollView.contentSize = CGSizeMake(500, 1000);
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
[refreshControl addTarget:self action:@selector(testRefresh:) forControlEvents:UIControlEventValueChanged];
[scrollView addSubview:refreshControl];
[self.view addSubview:scrollView];
}
- (void)testRefresh:(UIRefreshControl *)refreshControl
{
refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:@"Refreshing data..."];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[NSThread sleepForTimeInterval:3];//for 3 seconds, prevent scrollview from bouncing back down (which would cover up the refresh view immediately and stop the user from even seeing the refresh text / animation)
dispatch_async(dispatch_get_main_queue(), ^{
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"MMM d, h:mm a"];
NSString *lastUpdate = [NSString stringWithFormat:@"Last updated on %@", [formatter stringFromDate:[NSDate date]]];
refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:lastUpdate];
[refreshControl endRefreshing];
NSLog(@"refresh end");
});
});
}
需要在单独的线程上进行数据更新，否则它将锁定主线程（UI用于更新UI）。因此，当主线程忙于更新数据时，UI也会被锁定或冻结，您永远不会看到平滑的动画或微调器。
编辑：好的，我正在做与OP相同的事情，我现在已经添加了一些文本（即“拉到刷新”），它确实需要回到主线程来更新该文本。
更新的答案。
您只需创建一个刷新控件的实例，并将其添加到滚动视图的顶部。然后，在委托方法中，您可以根据需要调整其行为。
添加到上面的答案，在某些情况下你不能设置contentSize（可能使用自动布局？）或者contentSize的高度小于或等于UIScrollView的高度。在这些情况下，UIRefreshControl将无法工作，因为UIScrollView不会反弹。
要解决此问题，请将属性alwaysBounceVertical设置为TRUE。
如果你有幸支持iOS 10+，你现在可以简单地设置refreshControl的UIScrollView。这与refreshControl上现有的UITableView的工作方式相同。
以下是在C＃/ Monotouch中执行此操作的方法。我无法在任何地方找到C＃的任何样本，所以这里是..谢谢Log139！
public override void ViewDidLoad ()
{
//Create a scrollview object
UIScrollView MainScrollView = new UIScrollView(new RectangleF (0, 0, 500, 600));
//set the content size bigger so that it will bounce
MainScrollView.ContentSize = new SizeF(500,650);
// initialise and set the refresh class variable
refresh = new UIRefreshControl();
refresh.AddTarget(RefreshEventHandler,UIControlEvent.ValueChanged);
MainScrollView.AddSubview (refresh);
}
private void RefreshEventHandler (object obj, EventArgs args)
{
System.Threading.ThreadPool.QueueUserWorkItem ((callback) => {
InvokeOnMainThread (delegate() {
System.Threading.Thread.Sleep (3000);
refresh.EndRefreshing ();
});
});
}
对于跳跃问题，Tim Norman's answer解决了它。
如果您使用swift2，这是swift版本：
import UIKit
class NoJumpRefreshScrollView: UIScrollView {
/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func drawRect(rect: CGRect) {
// Drawing code
}
*/
override var contentInset:UIEdgeInsets {
willSet {
if self.tracking {
let diff = newValue.top - self.contentInset.top;
var translation = self.panGestureRecognizer.translationInView(self)
translation.y -= diff * 3.0 / 2.0
self.panGestureRecognizer.setTranslation(translation, inView: self)
}
}
}
}
如何在Swift 3中做到这一点：
override func viewDidLoad() {
super.viewDidLoad()
let scroll = UIScrollView()
scroll.isScrollEnabled = true
view.addSubview(scroll)
let refreshControl = UIRefreshControl()
refreshControl.addTarget(self, action: #selector(pullToRefresh(_:)), for: .valueChanged)
scroll.addSubview(refreshControl)
}
func pullToRefresh(_ refreshControl: UIRefreshControl) {
// Update your conntent here
refreshControl.endRefreshing()
}
我让UIRefreshControl在UIScrollView内正常工作。我继承了UIScrollView，阻止了对contentInset的更改并覆盖了contentOffset setter：
class ScrollViewForRefreshControl : UIScrollView {
override var contentOffset : CGPoint {
get {return super.contentOffset }
set {
if newValue.y < -_contentInset.top || _contentInset.top == 0 {
super.contentOffset = newValue
}
}
}
private var _contentInset = UIEdgeInsetsZero
override var contentInset : UIEdgeInsets {
get { return _contentInset}
set {
_contentInset = newValue
if newValue.top == 0 && contentOffset.y < 0 {
self.setContentOffset(CGPointZero, animated: true)
}
}
}
}
对于Jumping问题，覆盖contentInset仅在iOS 9之前解决它。我只是尝试了一种避免跳转问题的方法：
let scrollView = UIScrollView()
let refresh = UIRefreshControl()
// scrollView.refreshControl = UIRefreshControl() this will cause the jump issue
refresh.addTarget(self, action: #selector(handleRefreshControl), for: .valueChanged)
scrollView.alwaysBounceVertical = true
//just add refreshControl and send it to back will avoid jump issue
scrollView.addSubview(refresh)
scrollView.sendSubviewToBack(refresh)
适用于iOS 9 10 11等等，我希望他们（Apple）能解决这个问题。
由于iOS 10 UIScrollView已经具有refreshControl属性。创建UIRefereshControl时会出现此refreshControl，并且指向此属性。
不再需要将UIRefereshControl添加为子视图。
func configureRefreshControl () {
// Add the refresh control to your UIScrollView object.
myScrollingView.refreshControl = UIRefreshControl()
myScrollingView.refreshControl?.addTarget(self, action:
#selector(handleRefreshControl),
for: .valueChanged)
}
@objc func handleRefreshControl() {
// Update your content…
// Dismiss the refresh control.
DispatchQueue.main.async {
self.myScrollingView.refreshControl?.endRefreshing()
}
}
UIRefreshControl对象是附加到任何UIScrollView对象的标准控件
代码和引用来自https://developer.apple.com/documentation/uikit/uirefreshcontrol