下载图片现在可以与NSURLSessionDataTask一起使用

Question

我将不赞成使用的iOS9代码迁移到iOS10，具体来说是这样的：

@interface IconDownloader : NSObject<NSURLConnectionDataDelegate,NSURLConnectionDelegate>{
    NSMutableData *receivedData;
}
@property(nonatomic,strong)CapabilityType *capability;
@property(nonatomic,strong)CapabilitiesItemView *item;
-(void)downloadIcon:(CapabilityType *)capability forItem:(CapabilitiesItemView *)item;
@end

@implementation IconDownloader
.
.
.
.
NSURLConnection *con=[[NSURLConnection alloc] initWithRequest:req delegate:self];
    [con start];

-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
    NSLog(@"DEPRECATED - didReceiveData"); 
    if(!receivedData){
        receivedData=[[NSMutableData alloc] initWithData:data];
    }else
        [receivedData appendData:data];
}

-(void)connectionDidFinishLoading:(NSURLConnection *)connection{
    NSLog(@"DEPRECATED - connectionDidFinishLoading"); 
    NSLog(@"NSURLConnection - COMPLETE, dataLength=%lu",(unsigned long)receivedData.length);
    NSLog(@"DataIOS7+: %@",receivedData);
    if(receivedData.length>0){
        UIImage *image=[UIImage imageWithData:receivedData];
        if(image){
            self.capability.icon=image;
            self.item.iconImageView.image=image;
        }
    }

此已弃用但可靠的代码可以完美运行。 当我尝试对iOS10 +进行适配时， image变量始终被初始化为null，而我的imageViews看起来是空白的：

NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:req
                                            completionHandler:^(NSData *data, NSURLResponse *response, NSError *error){
                                      NSLog(@"NSURLSessionDataTask - COMPLETE, error=%@",error);
                                      if(!error){
                                          NSLog(@"NSURLSessionDataTask - COMPLETE, dataLength=%lu",(unsigned long)data.length);
                                          NSLog(@"DataIOS10: %@",data);
                                          if(data.length>0){
                                              NSData *dataIOS10 = [[NSData alloc] initWithBase64EncodedString:[[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding] options:NSDataBase64DecodingIgnoreUnknownCharacters];
                                              UIImage *image=[UIImage imageWithData:dataIOS10];

                                              dispatch_async(dispatch_get_main_queue(), ^{
                                              if(image){
                                                  NSLog(@"NSURLSessionDataTask - COMPLETE, IMAGE OK");
                                                  self.capability.icon=image;
                                                  self.item.iconImageView.image=image;
                                              }
                                              else{
                                                  NSLog(@"NSURLSessionDataTask - COMPLETE, IMAGE ERROR");
                                                  self.capability.icon=image;//Lets try shoving that data there, just in case LOL
                                                  self.item.iconImageView.image=image;
                                              }
                                              });
                                          }
                                      }
                                  }];
[dataTask resume];

额外，请求似乎可以很好地到达：

NSURLSessionDataTask - COMPLETE, response=<NSHTTPURLResponse: 0x15e450f0> { URL: https://abc.SOMESERVER.net/prod/wcid/iphone/icon_fun.png } { status code: 200, headers {
    "Accept-Ranges" = bytes;
    Connection = "keep-alive";
    "Content-Length" = 6416;
    "Content-Type" = "image/png";
    Date = "Tue, 31 Jan 2017 13:11:05 GMT";
    Etag = "\"e554f6246076dc4eddf589f9552608b5\"";
    "Last-Modified" = "Mon, 28 Apr 2014 13:30:15 GMT";
    Server = AmazonS3;
    Via = "1.1 dc81da318a4ae20e51ccfd9463219596.cloudfront.net (CloudFront)";
    "X-Amz-Cf-Id" = "xlj4_3IUrjctZLrGlegXoZbrmTYqd_ahcGzG3K2glG3m6keedPk6mQ==";
    "X-Cache" = "Miss from cloudfront";
    "x-amz-meta-cb-modifiedtime" = "Thu, 31 Oct 2013 15:26:16 GMT";
} }

尽管始终具有非零字节大小，并且具有或不具有这种精美的Base64编码，图像始终将为null ...它始终会失败。 我什至尝试在主线程上运行代码。 有什么想法吗？

Answer 1

好的出发点是检查同步呼叫是否正常工作，即

NSData * imgData = [[NSData分配] initWithContentsOfURL：url]; UIImage * image = [UIImage imageWithData：imgData];

如果数据无法成像，则您的请求有问题。