UITableView 方法“indexPathForRowAtPoint:"的奇怪行为 [英] Weird behavior of UITableView method "indexPathForRowAtPoint:"

问题描述

如下面的代码所示，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(因为我认为 indexPath 将始终为零).但是，当我点击部分编号大于 2 的部分标题中的头像时，NSLog 不会被调用.很奇怪，有人知道这是怎么回事吗?

As show in the following code, when the tableview is stretched (never scrolled up), the NSLog(@"tap is not on the tableview cell") will always be called (as i thought the indexPath will always be nil). But when i tap the avatar in the section header with section number greater than 2, the NSLog does not get called. It is weird, anyone know what's going on here?

-(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");
    }
}

推荐答案

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.

Your tap location is the location in the header, not a cell, so it would never match a cell indexPath.

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

You could probably set the tag for the avatar view to be the section number in viewForHeaderInSection and then retrieve the section number in handleTapGesture via sender.view.tag. For example:

-(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);
}

这篇关于UITableView 方法“indexPathForRowAtPoint:"的奇怪行为的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！