iPhone SDK - 如何使用动画以编程方式滚动UITableView？

Question

How would I scroll a UITableView to a specific position with an animation?

Currently I'm using this code to jump to a position:

 //tableController -> viewDidLoad
 [self.tableView reloadData];
 NSIndexPath *indexPath = [NSIndexPath indexPathForRow:row inSection:0];
 [self.tableView scrollToRowAtIndexPath:indexPath
                       atScrollPosition:UITableViewScrollPositionTop
                               animated:YES];

The problem with this code is, that the table jumps right to the right position without any animation. Is there any way to enable the animation or set the duration?

Thanks for any help.

Answer 1

It works fine for me:

-(void) viewDidAppear:(BOOL)animated{
    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:n inSection:0];
    [self.tableView scrollToRowAtIndexPath:indexPath
                    atScrollPosition:UITableViewScrollPositionTop
                            animated:YES];

}

To be sure that this is called only once, you can make a verification like this:

if(!isInitialized){
   isInitialized = YES;
   ....
}

Answer 2

Try commenting out the reloadData call. If I'm understanding your question correctly, and you're in viewDidLoad , you should not need to call it anyway.

Also, if you've just gotten done pushing the view controller, you won't get an animated scroll. You'll have to insert a delay (I've found a quarter second works well) between the time that viewDidLoad was called and when your animation starts.

Answer 3

I have two suggestions for you to investigate:

1. Are you running your app on the simulator or the iPhone itself? I have noticed some animations behave differently in the simulator.

2. Is it possible you are calling scrollToRowAtIndexPath:atScrollPosition:animated twice in quick succession? This can 'confuse' the animation. You should call this function only once while processing a given event.

Answer 4

我知道这可能为时已晚，但也许对其他人有帮助，现在你可以用[tableView scrollsToTop]滚动一个表。