Question

我有按钮的自定义单元格。点击按钮我从服务器下载视频。在下载过程中，我需要显示活动指示符，但它不会显示activityindicatorview。

代码：

 RBFriendChatTableViewCell *Cell = [ tableView dequeueReusableCellWithIdentifier:Identifier];
 [Cell.m_btnDownLoad addTarget:self action:@selector(downLoadImage:) forControlEvents:UIControlEventTouchUpInside];

-(void)downLoadImage:(UIbutton *)sender{
indicator = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
     indicator.center = CGPointMake(5, 5);
     [sender addSubview:indicator];
     [indicator startAnimating]
     NSString *strUrl = [NSString stringWithFormat:@"%@%@",chatImage,[dicChatList objectForKey:@"file"]];
                NSURL *url=[[NSURL alloc] initWithString:strUrl];
                NSData *movieData = [NSData dataWithContentsOfURL:url];
                NSURL *fileURL = [self grabFileURL:[dicChatList objectForKey:@"file"]];
                [movieData writeToURL:fileURL atomically:YES];
                [m_arrDownloadVideoName addObject:[dicChatList objectForKey:@"file"]];
}

Answer 1

你需要在主线程中更新UI，你正在同一个线程中下载视频，它应该在后台Asynch线程中完成，对于你当前的情况，修复后可能会有所帮助，但最好在后台进行下载并在完成后更新UI。

-(void)downLoadImage:(UIbutton *)sender{

    dispatch_async(dispatch_get_main_queue(), ^{
        indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle : UIActivityIndicatorViewStyleGray];
        indicator.center = CGPointMake(5, 5);
        [sender addSubview:indicator];
        [indicator startAnimating];
              });
    NSString *strUrl = [NSString stringWithFormat:@"%@%@",chatImage,[dicChatList objectForKey:@"file"]];
    NSURL *url=[[NSURL alloc] initWithString:strUrl];
    NSData *movieData = [NSData dataWithContentsOfURL:url];
    NSURL *fileURL = [self grabFileURL:[dicChatList objectForKey:@"file"]];
    [movieData writeToURL:fileURL atomically:YES];
    [m_arrDownloadVideoName addObject:[dicChatList objectForKey:@"file"]];
}

在自定义单元格按钮上显示活动指示

1 个答案: