How can I get the UITableView scroll position so I can save it?

Question

Is there any way to find out which UITableViewCell is at the top of the scroll window?

I'd like to get the current scroll position so that I can save it when the app exits. When the app gets started I want to scroll to the position it was at when it last exited.

Massage

This can also be achieved as <#55327730> – Hemispheroid

Answer 1

You can easily grab the exact offset of the table view by looking at its contentOffset property. For the vertical scroll, look at:

tableView.contentOffset.y;

Boatswain

That's a CGPoint in the scroll view, I'm not sure how I can tell which UITableViewCell that corresponds to. – Massage

You don't need the cell if you use the offset; just set the offset when you re-enter the view. However, if you MUST know the cell at the top, just use: [tableView indexPathForRowAtPoint: CGPointMake(0, 0)]; – Boatswain

using contentOffset works perfectly, it returns the scroll position exactly where it was when the app last quit. Thanks! I didn't need to know which cell it was after all. – Massage

for the c# user use this case: tableView.ContentOffset.Y; – Milks

Answer 2

The accepted solution only works if you know the size of all table view items. With auto sizing/estimated size that is not always true.

One alternative is to save the first visible item and scroll to it.

You can get the first visible item indexPath with:

savedIndex = tableView.indexPathsForVisibleRows?.first

Then scroll to it by doing:

tableView.scrollToRowAtIndexPath(savedIndex, atScrollPosition: .Top, animated: false)

Shakti

Answer 3

Make sure you can load in viewWillAppear and not viewDidLoad (tested iOS 9). ViewWillAppear is when view has finished layout - there is differences in the outcome.

-(void) viewWillAppear:(BOOL)animated {
    NSUserDefaults *lightData = [NSUserDefaults standardUserDefaults];
    [self.tableView setContentOffset:CGPointMake(0, [lightData floatForKey:@"yValue"])];
}

-(void) viewWillDisappear:(BOOL)animated {
    NSUserDefaults *lightData = [NSUserDefaults standardUserDefaults];
    [lightData setFloat:self.tableView.contentOffset.y forKey:@"yValue"];
    [lightData synchronize];
}

Reifel