如何在ios中使用UIImageView + AFNetworking异步加载图像

我用这个：

UIImage *image = [UIImage imageWithData: [NSData dataWithContentsOfURL: [NSURL URLWithString:@"http://sofzh.miximages.com/ios/ios_Loading-Spinners.gif"]]]; 

但这花费了太多时间。 我想使用AFNetworking来加快加载速度。

任何帮助，将不胜感激。

Answer 1

您可以使用SDWebImage

它支持异步下载和缓存。

用法

只需#import UIImageView+WebCache.h标头

  [imgView sd_setImageWithURL:Url_Of_The_Image placeholderImage:[UIImage imageNamed:@"Sampleimage.png"]]; 

Answer 2

 #import "UIImageView+AFNetworking.h" //... [self.imageView setImageWithURL:[NSURL URLWithString:@"image_url"]]; 

Answer 3

你可以像这样加载异步图像：

 dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul); dispatch_async(queue, ^{ NSData * imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]]; dispatch_async(dispatch_get_main_queue(), ^{ UIImage *image = [UIImage imageWithData:imageData]; }); }); 

我需要将此图像设置为imageview，因此请尝试使用此：

 UIImageView *img = [[UIImageView alloc] initWithFrame:FRAME]; dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul); dispatch_async(queue, ^{ NSData * imageData = [NSData dataWithContentsOfURL:[NSURL URLWithString:[url stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]]]; dispatch_async(dispatch_get_main_queue(), ^{ UIImage *image = [UIImage imageWithData:imageData]; img.image = image; img.contentMode = UIViewContentModeScaleAspectFill; }); }); 

Answer 4

没有答案似乎完全处理这个，所以，有更多的信息.​​…..

首先，您应该为UIImageView包含AFNetworking类别：

 #import "UIImageView+AFNetworking.h" 

如果你正在使用CocoaPods，这一行应该是：

 #import  

之后，你应该至少有一个UIImageView （我假设你连接了一个IBOutlet ）：

 @property (weak, nonatomic) IBOutlet UIImageView *myImageView; 

然后你可以在代码中加载你的图像：

 // Define a placeholder image that will be shown while the remote image // loads. If you don't want a placeholder image, just set it to nil. // Note that this placeholder image is local (it should be in your // asset files/collection). UIImage *myPlaceholderImage = nil; // Or use [UIImage imageNamed:@"..."]; // First, cancel other tasks that could be downloading images. // If you only do this once, this is probably not needed, but it's not harmful to // always have it before loading an image with setImageWithURL: and derivatives. [self.myImageView cancelImageDownloadTask]; // Set up a NSURL for the image you want. // I'm gonna use this wonderful owl: https://www.smashingmagazine.com/wp-content/uploads/2015/06/10-dithering-opt.jpg NSURL *imageURL = [NSURL URLWithString:@"http://sofzh.miximages.com/ios/www.smashingmagazine.com"]; // Check if the URL is valid if ( imageURL ) { // The URL is valid so we'll use it to load the image asynchronously. // Pass the placeholder image that will be shown while the // remote image loads. [self.myImageView setImageWithURL:imageURL placeholderImage:myPlaceholderImage]; } else { // The imageURL is invalid, just show the placeholder image. dispatch_async(dispatch_get_main_queue(), ^{ self.myImageView.image = myPlaceholderImage; }); } 

如果出于任何原因，在将其传递给UIImageView之前需要对远程映像执行某些操作 ，则可以使用setImageWithURLRequest:placeholderImage:success:failure:方法。 我将在模板模式下将收到的UIImage转换为另一个UIImage ，因此它将使用UIImageView的tintColor进行着色（当然，这个猫头鹰的图像看起来不太好，这应该是一个透明的普通图标） ：

 UIImage *placeholderImage = nil; NSURL *imageURL = [NSURL URLWithString:@"http://sofzh.miximages.com/ios/www.smashingmagazine.com"]; if ( imageURL ) { // Check NSURLRequestCachePolicy enumeration for other values. // 60 seconds in timeoutInterval is the default for iOS. NSURLRequest *imageRequest = [NSURLRequest requestWithURL:imageURL cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:60.0f]; [self.myImageView cancelImageDownloadTask]; // We'll keep a weak reference to our UIImageView so it won't have // any possibility of being retained by our success/failure blocks. __weak typeof(self.myImageView) weakImageView = self.myImageView; dispatch_async(dispatch_get_main_queue(), ^{ [self.myImageView setImageWithURLRequest:imageRequest placeholderImage:placeholderImage success:^(NSURLRequest * _Nonnull request, NSHTTPURLResponse * _Nullable response, UIImage * _Nonnull image) { UIImage *tintedImage = [image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate]; weakImageView.image = tintedImage; } failure:^(NSURLRequest * _Nonnull request, NSHTTPURLResponse * _Nullable response, NSError * _Nonnull error) { weakImageView.image = placeholderImage; }]; }); } else { dispatch_async(dispatch_get_main_queue(), ^{ self.myImageView.image = placeholderImage; }); } 

是的，我知道这是一个老问题，但这应该作为参考。

Answer 5

哈内克也会做这个工作。

 [imageView hnk_setImageFromURL:url]; 

如果你想加载AFNetworking ：

 [self.someImageView setImageWithURL:[NSURL URLWithString:@"urlOfImage"]];