需求：

1. UITableView 右側(cè)有索引
2. sectionHeader禁止懸浮
   3.點擊索引，sectionHeader在最上方正常顯示

解決方案

1. UITableView 右側(cè)有索引 所以只能選擇plain模式不能選擇Grouped
   2.plain模式的sectionHeader是懸浮的，滾動時候永遠在最頂端，直到下個sectionHeader顯示到頂端。
   解決：重寫scrollView滾動代理方法

-(void)scrollViewDidScroll:(UIScrollView *)scrollView {
    if (scrollView == self.tableView)
    {
        CGFloat sectionHeaderHeight = 44;  //自定義的sectionHeaderHeight
        if (scrollView.contentOffset.y<=sectionHeaderHeight && scrollView.contentOffset.y>=0) {
            scrollView.contentInset = UIEdgeInsetsMake(-scrollView.contentOffset.y, 0, 0, 0);
        } else if (scrollView.contentOffset.y>=sectionHeaderHeight) {
            scrollView.contentInset = UIEdgeInsetsMake(-sectionHeaderHeight, 0, 0, 0);
        }
    }
}

3.重寫完后發(fā)現(xiàn)，點右側(cè)索引，sectionHeader是不顯示的，只顯示第一個row內(nèi)容
解決： 找到點擊索引方法，增加標(biāo)示，告知scrollView不需要更改contentInset

-(NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index{
    _doNotChangeOffSet = YES;
    // 獲取所點目錄對應(yīng)的indexPath值
    NSIndexPath *selectIndexPath = [NSIndexPath indexPathForRow:0  inSection:index];
    // 讓table滾動到對應(yīng)的indexPath位置
    [tableView scrollToRowAtIndexPath:selectIndexPath atScrollPosition:UITableViewScrollPositionBottom animated:NO];
    _doNotChangeOffSet = NO;
    return index;
}

-(void)scrollViewDidScroll:(UIScrollView *)scrollView {
    if (scrollView == self.tableView)
    {
        if (_doNotChangeOffSet) {
            scrollView.contentInset = UIEdgeInsetsMake(0, 0, 0, 0);
            return;
        }
        CGFloat sectionHeaderHeight = 44;  //自定義的sectionHeaderHeight
        if (scrollView.contentOffset.y<=sectionHeaderHeight && scrollView.contentOffset.y>=0) {
            scrollView.contentInset = UIEdgeInsetsMake(-scrollView.contentOffset.y, 0, 0, 0);
        } else if (scrollView.contentOffset.y>=sectionHeaderHeight) {
            scrollView.contentInset = UIEdgeInsetsMake(-sectionHeaderHeight, 0, 0, 0);
        }
    }
}

完美解決。