ios NSURLSession 委托 vs. completionHandler
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NSURLSession delegate vs. completionHandler
提问by AndrewSB
I've always used completion handlers. With NSURLConnectionand now with NSURLSession. It's led to my code being really untidy, especially I have request within request within request.
我一直使用完成处理程序。随着NSURLConnection和现在NSURLSession。这导致我的代码真的很乱，尤其是我在请求中请求中。
I wanted to try using delegates in NSURLSessionto implement something I've done untidily with NSURLConnection.
我想尝试使用委托NSURLSession来实现我用NSURLConnection.
So I created a NSURLSession, and created a dataTask:
所以我创建了一个NSURLSession，并创建了一个dataTask：
NSURLSessionDataTask *dataTask = [overallSession dataTaskWithURL:url
completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
if(error == nil)
{
NSString * text = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
NSLog(@"Data = %@",text);
}
}];
[dataTask resume];
Right now I have a completionHandlerfor the response, how would I switch to delegates to manage the response and data? And can I add another dataTaskfrom the delegate of this one? Using the cookies that this dataTaskcreated and placed into the session?
现在我有一个completionHandler响应，我将如何切换到代表来管理响应和数据？我可以dataTask从这个代表中添加另一个吗？使用它dataTask创建并放置到会话中的 cookie ？
回答by Vacca
If you want to add a custom delegate class, you need to implement the NSURLSessionDataDelegateand NSURLSessionTaskDelegateprotocols at the minimum.
如果要添加自定义委托类，至少需要实现NSURLSessionDataDelegate和NSURLSessionTaskDelegate协议。
With the methods:
使用方法：
NSURLSessionDataDelegate - get continuous status of your request
NSURLSessionDataDelegate - 获取请求的连续状态
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveResponse:(NSURLResponse *)response
completionHandler:(void (^)(NSURLSessionResponseDisposition disposition))completionHandler {
receivedData=nil; receivedData=[[NSMutableData alloc] init];
[receivedData setLength:0];
completionHandler(NSURLSessionResponseAllow);
}
NSURLSessionDataDelegate
NSURLSessionDataDelegate
-(void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask
didReceiveData:(NSData *)data {
[receivedData appendData:data];
}
NSURLSessionTaskDelegate
NSURLSessionTaskDelegate
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task
didCompleteWithError:(NSError *)error {
if (error) {
// Handle error
}
else {
NSDictionary* response=(NSDictionary*)[NSJSONSerialization JSONObjectWithData:receivedData options:kNilOptions error:&tempError];
// perform operations for the NSDictionary response
}
If you want to separate the delegate code (middle layer) from your calling class (generally its good practice to have separate class/layer for network calls), the delegate of NSURLSession has to be :-
如果您想将委托代码（中间层）与您的调用类分开（通常是为网络调用提供单独的类/层的好做法），NSURLSession 的委托必须是：-
NSURLSession *session=[NSURLSession sessionWithConfiguration:sessionConfig delegate:myCustomDelegateClass delegateQueue:nil];
Ref Links:
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