MBProgressHUD 与 NSURLConnection XCode 7

Question

背景：

请不要将此标记为重复。我已经尝试了所有其他相关的帖子，但它们对我不起作用。我看过无数的例子（StackOverflow/MBProgressHUD Demo/etc.）试图让它工作。我觉得大多数示例都已过时，因为某些方法已被弃用。这是我得到的最接近的。

我想让代码做什么：

在我开始连接到 JSON 之前，MBProgress HUD 应该显示带有“正在准备”的默认加载屏幕。当我连接时，我希望在收到响应时将模式更改为 AnnularDeterminate。加载完成后，我希望进度条显示将数据添加到字典的进度。完成后，将模式更改为显示复选标记图像和“已完成”的 CustomView。

问题：

将显示 MBProgress HUD。但是，它仅显示默认加载屏幕，其下方带有“正在准备...”，然后在进度为 1.0 后会显示“已完成”并带有复选标记自定义视图。中间没有我更新进度的确定视图。

---

我的代码

- (void)viewDidLoad
{
    buildingsDataArray = [[NSMutableArray alloc] init];
    MBProgressHUD *HUD = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
    HUD.delegate = self;
    HUD.label.text = NSLocalizedString(@"Preparing...", @"HUD preparing title");
    [self connect];
    NSLog(@"End of setup");
}

- (void)connect
{
    NSURLRequest *request =[NSURLRequest requestWithURL:[NSURL URLWithString:buildingList]];
    connection = [NSURLConnection connectionWithRequest:request delegate:self];
    [connection start];

   NSLog(@"End of connect");
}


// Connection delegate
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
    NSLog(@"connection received response");
    [MBProgressHUD HUDForView:self.view].mode = MBProgressHUDModeAnnularDeterminate;
    NSLog(@"Changed mode");
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    [webData appendData:data];
    NSLog(@"connection received data");
    [MBProgressHUD HUDForView:self.view].progress = 0.0f;
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
    NSLog(@"Fail with error - %@ %@", [error localizedDescription], [[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
    if ([[error localizedDescription] isEqualToString:@"The Internet connection appears to be offline."]) {
        //do something
    }
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSArray *allDataArray = [NSJSONSerialization JSONObjectWithData:webData options:0 error:nil];
    float count = [allDataArray count];
    float c=1;
    if ([buildingsDataArray count]!=0)
        [buildingsDataArray removeAllObjects];
    for (NSDictionary *dataDict in allDataArray){ //from 1 to 6
        if ([[dataDict objectForKeyedSubscript:@"id"] intValue] != 0)
            [buildingsDataArray addObject:dataDict];
            usleep(200000);
            float p = c/count;
            [MBProgressHUD HUDForView:self.view].progress = p;
            NSLog(@"Progress: %f", [MBProgressHUD HUDForView:self.view].progress);
        });
        c++;
    }
    [MBProgressHUD HUDForView:self.view].customView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"Checkmark.png"]];
    [MBProgressHUD HUDForView:self.view].label.text = NSLocalizedString(@"Completed", @"HUD done title");
    [MBProgressHUD HUDForView:self.view].mode = MBProgressHUDModeCustomView;
    [[MBProgressHUD HUDForView:self.view] hideAnimated:YES afterDelay:1.0f];
}

这是我的控制台输出

End of connect
End of setup
connection received response
Changed mode
connection received data
connection finished loading
Progress: 0.166667
Progress: 0.333333
Progress: 0.500000
Progress: 0.666667
Progress: 0.833333
Progress: 1.000000

---

其他 cmets

当我尝试添加时

dispatch_async(dispatch_get_main_queue()

在我的连接委托内的所有 MBProgress 方法调用之外， 我再次获得默认加载屏幕。但是在进度达到 1.0 后，确定的加载屏幕视图显示（完全加载）“已完成”，然后在延迟 1.0 后消失。两者之间仍然没有加载过程。此外，复选标记图像永远不会显示。我不认为这是这样做的方法。

我这样做时的输出是：

End of connect
End of doSetup
connection received response
connection received data
connection finished loading
Changed mode
Progress: 0.166667
Progress: 0.333333
Progress: 0.500000
Progress: 0.666667
Progress: 0.833333
Progress: 1.000000

Answer 1

这是一个有用的参考，它基于不同线程上的 UICalls： Is there a way to make drawRect work right NOW?

这是有效的：

NSURLConnection 在主线程上被调用。因此，直到连接委托调用完成后，我的所有 UI 更新才会发生。

所以为了解决这个问题，我将连接放在后台线程中。

- (void)viewDidLoad{
    //...

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),^{
        NSURL *URL = [NSURL URLWithString:buildingList];
        NSMutableURLRequest *request =[NSMutableURLRequest requestWithURL:URL];
        connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];
        [connection setDelegateQueue:[[NSOperationQueue alloc] init]];
        [connection start];
    });

}

在连接委托方法中，我用

包围了每个 MBProgress 调用

dispatch_async(dispatch_get_main_queue(), ^{
    //...
}

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希望这对其他人有所帮助。我花了一整天的时间，这是一个如此简单的误解......