外部获取IndexPath的几种方式（关联对象等）

一、单击某个cell中的button获取indexPath

1、 一般方式

- (void)buttonAction:(UIButton *)sender
     {
        UITableViewCell *cell = (UITableViewCell *)[[sender superview] superview]; 
        NSIndexPath *indexPath = [_tableView indexPathForCell:cell];  
        NSLog(@"indexPath is = %i",indexPath.row); 
     }

2、runtime添加属性方式，即关联对象的方式

//runtime 关联对象
     这种方式首先引入#import 

     - (UITableViewCell *)tableView:(UITableView *)tableVie cellForRowAtIndexPath:(NSIndexPath *)indexPath
     {
         static NSString *identiStr = @"cellID";
         UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:identiStr];
         if (cell == nil)
         {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:identiStr];
            UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
            button.frame = CGRectMake(0, 0, 100, 33);

            [button addTarget:self action:@selector(buttonAction:) forControlEvents:UIControlEventTouchUpInside];
            [button setTitleColor:[UIColor redColor] forState:UIControlStateNormal];
            button.tag = 110 + indexPath.row;
            [cell.contentView addSubview:button];
          }
          UIButton *button = (UIButton *)[cell.contentView viewWithTag:110];
         //runtime 关联对象
         objc_setAssociatedObject(button, @"button", indexPath, OBJC_ASSOCIATION_ASSIGN);
         [button setTitle:dataSource[indexPath.row] forState:UIControlStateNormal];

         return cell;     
     }
    //事件触发 runtime 获取关联的对象
     - (void)buttonAction:(UIButton *)sender
     {
        //runtime 获取关联的对象
        UITableViewCell *cell = objc_getAssociatedObject(sender, @"button");
        NSIndexPath *indexPath = [_tableView indexPathForCell:cell];
        NSLog(@"indexPath is = %ld",indexPath.row);
     }

二、已知具体row，获取indexPath

- (void) refreshLessTime
{
    for (int row = 0; row < leftTimeArr.count; row ++)
    {
          NSIndexPath *indexPath = [NSIndexPath indexPathForItem: row inSection:0];
          UITableViewCell *cell = (UITableViewCell *)[_tableView cellForRowAtIndexPath:indexPath];
          UILabel *remainingTimeLabel = (UILabel *)[[cell.contentView viewWithTag:500] viewWithTag:501];
          remainingTimeLabel.text = [leftTimeArr objectAtIndex:indexPath.row];
     }
}