UITableView 方法“indexPathForRowAtPoint:”的奇怪行为

Question

如以下代码所示，当 tableview 被拉伸（从不向上滚动）时，NSLog(@"tap is not on the tableview cell") 将始终被调用（我认为 indexPath 将始终为 nil）。但是，当我在节号大于 2 的节标题中点击头像时，NSLog 不会被调用。很奇怪，有人知道这是怎么回事吗？

-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
 ...
     UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture:)];
     tapGesture.numberOfTapsRequired = 1;
     [avatar addGestureRecognizer:tapGesture];
     //avatar is UIImageView and the user interaction is enabled.
     [headerView addSubview: aMessageAvatar];
     return headerView;
 ...

}


-(void)handleTapGesture:(UITapGestureRecognizer *)sender
{
    CGPoint point = [sender locationInView:self.tableView];
    NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:point];
    if (!indexPath) {
    NSLog(@"tap is not on the tableview cell");
    }
}

Answer 1

您的点击位置是标题中的位置，而不是单元格，因此它永远不会匹配单元格indexPath。

您可以将avatar 视图的tag 设置为viewForHeaderInSection 中的节号，然后通过sender.view.tag 检索handleTapGesture 中的节号。例如：

-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
 ...
     UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapGesture:)];
     tapGesture.numberOfTapsRequired = 1;
     avatar.tag = section;                // save the section number in the tag
     avatar.userInteractionEnabled = YES; // and make sure to enable touches
     [avatar addGestureRecognizer:tapGesture];
     //avatar is UIImageView and the user interaction is enabled.
     [headerView addSubview: aMessageAvatar];
     return headerView;
 ...

}

-(void)handleTapGesture:(UITapGestureRecognizer *)sender
{
    NSInteger section = sender.view.tag;
    NSLog(@"In section %d", section);
}