UITableView节标题为空白且闪烁 [英] UITableView section headers are blank and flickering

问题描述

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];

if ([tempArray containsObject: [sectionInfo indexTitle]])
{
    [tempArray removeObjectAtIndex:[tempArray indexOfObject:[sectionInfo indexTitle]]];     
    return nil;
}else
{
    [tempArray addObject: [sectionInfo indexTitle]];
    return [sectionInfo indexTitle];

}
return [sectionInfo indexTitle];

}

上面的代码按字母顺序对单元格进行分组，但是显示空白的灰色标题，而不是适当的标题.可能是因为我没有指定标题的数量吗?这自然是字母表中每个字母的单个标头.还有其他想法，为什么单元格标头在我滚动时会从白色闪烁为灰色，从灰色闪烁为白色?

The code above groups the cells in alphabetical order but displays a blank gray header instead of the appropriate title. Could this possibly be because I did not specify the number of headers? This would naturally be a single header for every letter in the alphabet. Any other ideas why the cell headers would flicker white to gray, gray to white as I scrolled?

推荐答案

重复调用tableView:titleForHeaderInSection:似乎交替返回[sectionInfo indexTitle]和nil.你为什么感到惊讶?

Repeated calls to tableView:titleForHeaderInSection: appear to return alternately [sectionInfo indexTitle] and nil. Why are you surprised?

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