当用户滑动并查看“删除”按钮时，如何更新UITableView单元格？

Question

I have UITableVIew table.

I implemented deleting in method tableView:commitEditingStyle:forRowAtIndexPath: of UITableViewDataSource Protocol.

All work fine here. Useful question on subject here Deleting table row with animation using core data .

But every cell shows timer which count down and I have issue with this.

I use NSTimer in following way:

timer = [NSTimer scheduledTimerWithTimeInterval:0.25 target:self
    selector:@selector(updateTickerHandler:) userInfo:nil repeats:YES];

...

- (void)updateTickerHandler:(NSTimer*)timer
{
    [tableView reloadData];
}

When user swipes to delete timer, button "Delete" disappear when [tableView reloadData]; called.

I want to implement updating timer count down values on table cells which allows user to use swipe with "Delete" smoothly.

How to achieve this?

Answer 1

I was not able to obtain working behaviour with the call:

[tableView reloadData];

The working solution is to update cell components manually and not to call [table reloadData]

Code of updateTickerHandler: could be updated in the following way:

- (void)updateTickerHandler:(NSTimer*)timer
{
    [tableView beginUpdates];


    // select visible cells only which we will update 
    NSArray *visibleIndices = [tableView indexPathsForVisibleRows];

    // iterate through visible cells
    for (NSIndexPath *visibleIndex in visibleIndices)
    {
        MyTableCell *cell = (MyTableCell*)
            [tableView cellForRowAtIndexPath:visibleIndex];

        // add here code to fill `cell` with actual values
        // visibleIndex can be used to retrieve corresponding data

        ...
    }

    [tableView endUpdates];
}

Answer 2

 - (void)updateTickerHandler:(NSTimer*)timer
{
 [Table beginUpdates];
 [Table reloadData];
 [Table endUpdates];
}