IOS 13 中的滚动问题

Question

In order to achieve scroll To bottom for a table view, I am using the below code.

extension UITableView {

func scrollToBottom(){
        let indexPath = IndexPath(
                row: self.numberOfRows(inSection:  self.numberOfSections -1) - 1, 
                section: self.numberOfSections - 1)
        self.scrollToRow(at: indexPath, at: .bottom, animated: true)
    }
}

This is working perfectly fine for all the devices whose versions are below 13, but in ios 13 it is not scrolling completely to last cell , it is stopping in between the last cell (approximate 40 pixel from bottom).

I also tried alternate ways by

1. setting content Offset
2. setting the scroll to visible rect all
3. having a delay for 1.0 seconds

but all of these having the same behaviour, not scrolling completely.

Answer 1

If you're facing this issue because of having different cells with different heights then below code will probably work for you:

private func moveTableViewToBottom(indexPath: IndexPath) {
    tableView.scrollToRow(at: indexPath, at: .bottom, animated: false)
    DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
        self.tableView.scrollToRow(at: indexPath, at: .bottom, animated: false)
    }
}

Answer 2

Try this

func scrollToBottom(){
    DispatchQueue.main.async {
        let indexPath = IndexPath(row: self.yourDataSourceArray-1, section: self.numberOfSections - 1)
        self.tableView.scrollToRow(at: indexPath, at: .bottom, animated: true)
    }
}

Answer 3

Thank Shivam Pokhriyal

It helps me work properly on iOS 13, But I don't know exactly why

Swift:

private func moveTableViewToBottom(indexPath: IndexPath) {
    tableView.scrollToRow(at: indexPath, at: .bottom, animated: false)
        if #available(iOS 13.0, *) {
            DispatchQueue.main.asyncAfter(deadline: .now() + 0.1) {
        self.tableView.scrollToRow(at: indexPath, at: .bottom, animated: false)
        }
    }
}

OC:

- (void)scrollToBottomAnimated:(BOOL)animated {

NSInteger rows = [self.tableView numberOfRowsInSection:0];
    if (rows > 0) {
        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:rows-1 inSection:0];
        [self.tableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionBottom animated:animated];
        if (@available(iOS 13.0, *)) {
            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
                                NSInteger rows = [self.tableView numberOfRowsInSection:0];
                if (rows > 0) {
                    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:rows-1 inSection:0];
                    [self.tableView scrollToRowAtIndexPath:indexPath atScrollPosition:UITableViewScrollPositionBottom animated:animated];
                }
            });
        } else {
            // Fallback on earlier versions
        }
    }
}