试试这个方法。它会起作用的。

[tblViewTerms performSelectorOnMainThread:@selector(dataLoadDoneWithLastTermIndex:) withObject:lastTermIndex waitUntilDone:YES];waitUntilDone:YES];

@interface UITableView (TableViewCompletion)

-(void)dataLoadDoneWithLastTermIndex:(NSNumber*)lastTermIndex;

@end

@implementation UITableView(TableViewCompletion)

-(void)dataLoadDoneWithLastTermIndex:(NSNumber*)lastTermIndex
{
    NSLog(@"dataLoadDone");

NSIndexPath* indexPath = [NSIndexPath indexPathForRow: [lastTermIndex integerValue] inSection: 0];

[self selectRowAtIndexPath:indexPath animated:YES scrollPosition:UITableViewScrollPositionNone];

}
@end

我将在表完全加载时执行。

另一个解决方案是你可以子类化UITableView。

只是提供另一种方法，基于补全是发送到cellForRow的“最后可见”单元格的思想。

// Will be set when reload is called
var lastIndexPathToDisplay: IndexPath?

typealias ReloadCompletion = ()->Void

var reloadCompletion: ReloadCompletion?

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

    // Setup cell

    if indexPath == self.lastIndexPathToDisplay {

        self.lastIndexPathToDisplay = nil

        self.reloadCompletion?()
        self.reloadCompletion = nil
    }

    // Return cell
...

func reloadData(completion: @escaping ReloadCompletion) {

    self.reloadCompletion = completion

    self.mainTable.reloadData()

    self.lastIndexPathToDisplay = self.mainTable.indexPathsForVisibleRows?.last
}

一个可能的问题是:如果reloadData()在lastIndexPathToDisplay被设置之前已经完成，“最后可见”单元格将在lastIndexPathToDisplay被设置之前显示，补全将不会被调用(并且将处于“等待”状态):

self.mainTable.reloadData()

// cellForRowAt could be finished here, before setting `lastIndexPathToDisplay`

self.lastIndexPathToDisplay = self.mainTable.indexPathsForVisibleRows?.last

如果反转，可能会在reloadData()之前通过滚动触发补全。

self.lastIndexPathToDisplay = self.mainTable.indexPathsForVisibleRows?.last

// cellForRowAt could trigger the completion by scrolling here since we arm 'lastIndexPathToDisplay' before 'reloadData()'

self.mainTable.reloadData()

如果你在viewDidLoad时重新加载数据，你可以把你的代码放到viewDidLayoutSubviews方法中。但是你应该小心viewDidLayoutSubviews可能会被多次调用。

迅速:

extension UITableView {
    func reloadData(completion:@escaping ()->()) {
        UIView.animate(withDuration: 0, animations: reloadData)
            { _ in completion() }
    } 
}

// ...somewhere later...

tableView.reloadData {
    print("done")
}

objective - c:

[UIView animateWithDuration:0 animations:^{
    [myTableView reloadData];
} completion:^(BOOL finished) {
    //Do something after that...
}];

尝试设置延迟时间:

[_tableView performSelector:@selector(reloadData) withObject:nil afterDelay:0.2];
[_activityIndicator performSelector:@selector(stopAnimating) withObject:nil afterDelay:0.2];

和一个UICollectionView版本，基于kolaworld的答案。

它需要测试。到目前为止，它在iOS 9.2和Xcode 9.2 beta 2上工作，将collectionView滚动到一个索引，作为一个闭包。

extension UICollectionView
{
    /// Calls reloadsData() on self, and ensures that the given closure is
    /// called after reloadData() has been completed.
    ///
    /// Discussion: reloadData() appears to be asynchronous. i.e. the
    /// reloading actually happens during the next layout pass. So, doing
    /// things like scrolling the collectionView immediately after a
    /// call to reloadData() can cause trouble.
    ///
    /// This method uses CATransaction to schedule the closure.

    func reloadDataThenPerform(_ closure: @escaping (() -> Void))
    {
        CATransaction.begin()
            CATransaction.setCompletionBlock(closure)
            self.reloadData()
        CATransaction.commit()
    }
}

用法:

myCollectionView.reloadDataThenPerform {
    myCollectionView.scrollToItem(at: indexPath,
            at: .centeredVertically,
            animated: true)
}