播放动画时的数据加载

Question

目前在我AppDelegate.m我的代码：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
    [self.window makeKeyAndVisible]; 
    CGRect rect = [[UIScreen mainScreen] bounds]; 
    UIImageView *imageView =[[UIImageView alloc] initWithFrame:rect]; 
    imageView.animationImages = [NSArray arrayWithObjects: 
           [UIImage imageNamed:@"Comp 2_00000.png"],..., nil]; 
    imageView.animationDuration = 6; 
    imageView.animationRepeatCount = 1; 
    [imageView startAnimating]; 
    [self.window addSubview:imageView]; 

    return YES; 
} 

起着动画我有一次我的观点没有在我ViewController.m加载代码加载一些数据需要大约5秒。

我加载数据这样的使用JSON和URL：

NSURL *url = [NSURL URLWithString:@"http://xxxxxxxx.co.uk/untitled%20folder/jsonimages.php"]; 
    NSData *jsonData = [NSData dataWithContentsOfURL:url]; 
    NSError *error = nil; 

    NSDictionary *result = [NSJSONSerialization JSONObjectWithData:jsonData 
                  options:NSJSONReadingMutableContainers error:&error]; 

反正是有对数据加载时要播放的动画？

Answer 1

创建一个辅助功能（使静态的，如果您需要重复使用）：

功能：

-(UIImageView *) InitImageView{  
    [self.window makeKeyAndVisible]; 
    CGRect rect = [[UIScreen mainScreen] bounds]; 
    UIImageView *imageView =[[UIImageView alloc] initWithFrame:rect]; 
    imageView.animationImages = [NSArray arrayWithObjects: 
          [UIImage imageNamed:@"Comp 2_00000.png"],..., nil]; 
    //imageView.animationDuration = 6; 
    imageView.animationRepeatCount = 1; 

    [self.view addSubview:imageView]; 

    return imageView; 
} 

Ansynchronous任务：

//Start Animation 
UIImageView *imageView = [self InitImageView]; 
[imageView startAnimating]; 

dispatch_queue_t queue = dispatch_queue_create("co.uk.bits.bots", NULL); 
dispatch_async(queue, ^{ 
NSURL *url = [NSURL URLWithString:@"http://xx.co.uk/jsonimages.php"]; 
    NSData *jsonData = [NSData dataWithContentsOfURL:url]; 
    NSError *error = nil; 

    NSDictionary *result = [NSJSONSerialization JSONObjectWithData:jsonData 
         options:NSJSONReadingMutableContainers error:&error]; 
    dispatch_async(dispatch_get_main_queue(), ^{ 
     //Stop Animation 
     [imageView stopAnimating]; 
    }); 
}); 

Answer 2

此代码可能会让您的应用在应用商店中被拒绝，因为它会强制用户在每次应用启动时等待6秒钟。苹果的指导方针表示应用程序的发布应该尽可能快。

您可以重构它，以便您的初始视图控制器可以在没有数据的情况下首先显示，然后在数据可用时递增更新它？

如果从网络加载数据，您也可以缓存它，以便后续启动速度更快。

Answer 3

你可以做的是调度数据请求，然后调用动画：

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ 
    NSURL *url = [NSURL URLWithString:@"http://xxxxxxxx.co.uk/untitled%20folder/jsonimages.php"]; 
    NSData *jsonData = [NSData dataWithContentsOfURL:url]; 
    NSError *error = nil; 

    NSDictionary *result = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&error]; 
     dispatch_async(dispatch_get_main_queue(), ^{ 
       //Main thread stuff, after loading the data 
       [self animate]; 
     }); 
}); 

....

- (void)animate { 
    CGRect rect = [[UIScreen mainScreen] bounds]; 
    UIImageView *imageView =[[UIImageView alloc] initWithFrame:rect]; 
    imageView.animationImages = [NSArray arrayWithObjects: 
           [UIImage imageNamed:@"Comp 2_00000.png"],..., nil]; 
    imageView.animationDuration = 6; 
    imageView.animationRepeatCount = 1; 
    [imageView startAnimating]; 
    [self.view addSubview:imageView]; 
}