iPhone SDK - How to scroll a UITableView programma

问题:

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.

回答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;
   ....
}

回答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.

回答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.

回答4:

I know it's maybe too late, but maybe it is help to others, now you can scroll a table just with [tableView scrollsToTop].