Question

我正在尝试使用GCD更新我的自定义标签，但我得到的是我用以下内容初始化标签的文字：

-(void)drawCardInfo{

    __block NSString *cardString;

    PPLinearLayoutLabelItem *cardDetails = [[PPLinearLayoutLabelItem alloc] initWithText:@"CREDIT CARD INFO" font:[PPFonts regular18] maxWidth:[LayoutValues getMaxWidthClipped]];
    [cardDetails setPaddingTop:20];
    [cardDetails setPaddingBottom:10];
    [self.topContainerContent addObject:cardDetails];

    PPLinearLayoutLabelItem *cardInfo = [[PPLinearLayoutLabelItem alloc] initWithText:@"Data" font:[PPFonts bold16] maxWidth:[LayoutValues getMaxWidthClipped]];
    [cardInfo setPaddingTop:0];
    [self.topContainerContent addObject:cardInfo];


    LinearLayoutHorizontalLine *line1 = [[LinearLayoutHorizontalLine alloc] initWithMaxWidth:[LayoutValues getMaxWidthClipped]];
    [self.topContainerContent addObject:line1];

    dispatch_async( dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{


        NSOperationQueue *networkQueue = [[NSOperationQueue alloc] init];
        networkQueue.maxConcurrentOperationCount = 5;
        NSURL *url = [NSURL URLWithString:@"https://xxxxxxxxxxxxxxxxxx"];
        NSURLRequest *request = [NSURLRequest requestWithURL:url];
        AFHTTPRequestOperation *operation = [[AFHTTPRequestOperation alloc]
                                             initWithRequest:request];
        [operation setCompletionBlockWithSuccess:^(AFHTTPRequestOperation *operation, id responseObject) {
         NSString *string = [[NSString alloc] initWithData:responseObject encoding:NSUTF8StringEncoding];


            if([string isEqualToString:@""]){

            } else {

                NSMutableDictionary *dict=[NSJSONSerialization JSONObjectWithData:[string dataUsingEncoding:NSUTF8StringEncoding] options:kNilOptions error:nil];
                NSString *cardType = [dict objectForKey:@"credit_card_type"];
                NSString *cardFinalFour = [dict objectForKey:@"credit_card_last_4"];
                cardString = [NSString stringWithFormat:@"%@ **** %@",cardType, cardFinalFour];


                NSLog(@"%@",cardString);

            }
            dispatch_async(dispatch_get_main_queue(), ^{ [cardInfo setText:cardString]; });

        } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
            NSLog(@"%s: AFHTTPRequestOperation error: %@", __FUNCTION__, error);
        }];

        [networkQueue addOperation:operation];

    });

}

我成功注销了证明网络调用在单独线程上运行正常的值。我的标签还没有更新。我该如何缓解这种情况？

Answer 1

看起来您正在尝试在后台线程中更新标签的文本。在主线程以外的任何地方更新UI元素并不是一个好主意，因为您永远不知道异步作业何时完成。

您可以使用以下方式进行操作：

获取主线程，然后更新文本标签
```
Sub
```
使用it("calls the totalBogof() function", function() { spyOn(basket, "totalBogof"); basket.total(); expect(basket.totalBogof).toHaveBeenCalled(); });
将dispatch_async(dispatch_get_main_queue(), ^{ //Code here to which needs to update the UI in the UI thread goes here });与依赖关系一起使用（这将是最长的）

iOS中的GCD未更新我的标签

1 个答案: