iOS UIImage传递旧图像

Question

在我的应用程序中，我使用API​​从服务器获取图像。使用下面的代码，它可以按照大小顺序获取图像，以更好的质量取代自己。

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ 
    NSURL *imageURL = [NSURL URLWithString: [NSString stringWithFormat:@"%@", [[[self.information objectForKey:@"images"]objectForKey:@"normal"] description]]]; 
    NSData *imageData = [NSData dataWithContentsOfURL:imageURL]; 
    self.shotImage = [UIImage imageWithData:imageData]; 
    self.image.image = self.shotImage; 
}); 

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ 
    NSURL *imageURL = [NSURL URLWithString: [NSString stringWithFormat:@"%@", [[[self.information objectForKey:@"images"]objectForKey:@"hidpi"] description]]]; 
    NSData *imageData = [NSData dataWithContentsOfURL:imageURL]; 
    UIImage *image = [UIImage imageWithData:imageData]; 
    self.image.image = self.shotImage; 
}); 

此外，如果你按图片，它会带你另一个ViewController，其中图像是全屏。

然而，即使我在点击它之前等待高质量的加载，在PrepareForSegue方法中，它仍然只能通过原始的低质量版本。

看到PrepareForSegue

-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender 
{ 
    FullSizeImageViewController *vc = [segue destinationViewController]; 
    UIImage *img = [[UIImage alloc] init]; 
    img = self.shotImage; 
    vc.shotImage = img; 
} 

Answer 1

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ 
    NSURL *imageURL = [NSURL URLWithString: [NSString stringWithFormat:@"%@", [[[self.information objectForKey:@"images"]objectForKey:@"hidpi"] description]]]; 
    NSData *imageData = [NSData dataWithContentsOfURL:imageURL]; 
    UIImage *image = [UIImage imageWithData:imageData]; 
    self.image.image = self.shotImage; 
}); 

下面的代码在这段代码看起来像你错过了这行：

self.shotImage = [UIImage imageWithData:imageData];