Question

Ok so I have a segmentedControl which I need to dynamically remove and add segments to. This piece of code will remove the first segment but then doesnt set the correct segment to be selected. The strange thing is when I print it out all the numbers are correct it is just the highlighted segement on the screen which is always out by -1.

 if ([outControl numberOfSegments]==4) {
                int previous = [outControl selectedSegmentIndex];
                if (previous>0) {
                    previous--;
                }
                [outControl removeSegmentAtIndex:0 animated:YES];

                NSLog(@"setting to %d with %d segments", previous ,[outControl numberOfSegments]);
                [outControl setSelectedSegmentIndex:previous];


            }

Here is the log setting to 1 with 3 segments. With this log segment 0 is actually selected in the control and I cannot press segment 1 as the control thinks it is selected?
I can press segment 0 though even though that is the one being displayed as selected.

Here is a screen grab to try and clarify my issue.

image

The text in the cell is correct as cell 1 is actually selected as you can see by the log. But the highlighted cell is 0!? Its driving me crazy. It all works when adding segments its only when removing I get the issue.

Can anyone see where its going wrong??

Many thanks

Jules

I have noticed that even if i do not set the new selected segment I get the same results ie the wrong segment is selected…..?? Also this is all coded with cellForRowAtIndexPath if that helps anyone?

Answer 1

The code looks right yet behaves (wrongly) just as you described. It seems that the control gets in an awkward state when changing the selection in the same turn of the run loop as the segment deletion. But this works:

-(void)setSegmentedSelection:(NSNumber *)indexNum {
    NSInteger index = [indexNum intValue];
    [outControl setSelectedSegmentIndex:index];
}

// then instead of setting the selected index after the segment is removed,
// let the run loop return...

[self performSelector:@selector(setSegmentedSelection:) withObject:[NSNumber numberWithInt:previous] afterDelay:0.0];

I’m surprised that it doesn’t work as you coded, but at least here’s a workaround until we figure it out.