Question

这可能是一个 question问题。如果有的话,则会问。

但是,在开展一个耗用网络服务的项目时,不胜枚举。我可以与网络服务连接,获得我所需要的数据。

我希望有一个方法,把从网络服务处获得的这种数据反馈给打电话者。唯一的问题是,数据只能从联通达尼西群岛脱盲法中获取,我无法从我的手法获得这一数据。

我的法典就是此部法典。

- (NSData *) dataForMethod:(NSString *)webMethod withPostString:(NSString *)postString
{
    NSURL *url = [NSURL URLWithString:[SigameWebServiceAddress stringByAppendingFormat:@"%@%@", @"/", webMethod]];
    NSMutableURLRequest *req = [NSMutableURLRequest requestWithURL:url];
    NSString *msgLength = [NSString stringWithFormat:@"%d", [postString length]];

    [req addValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    [req addValue:msgLength forHTTPHeaderField:@"Content-Length"];
    [req setHTTPMethod:@"POST"];
    [req setHTTPBody: [postString dataUsingEncoding:NSUTF8StringEncoding]];

    conn = [[NSURLConnection alloc] initWithRequest:req delegate:self];
    if (conn) 
    {
        webData = [NSMutableData data];
    }   

    // I WOULD LIKE TO RETURN WEBDATA TO THE CALLER HERE, BUT WEBDATA IS EMPTY NOW, THE  
    //connectionDidFinishLoading ONLY GETS CALLED WITH THE DATA I WANT AFTER THE COMPILER
    //IS DONE EXECUTING MY METHOD.
}

-(void) connection:(NSURLConnection *) connection didReceiveResponse:(NSURLResponse *) response 
{
    [webData setLength: 0];
}

-(void) connection:(NSURLConnection *) connection didReceiveData:(NSData *) data 
{
    [webData appendData:data];
}

-(void) connection:(NSURLConnection *) connection didFailWithError:(NSError *) error 
{
    NSLog(@"FATAL ERROR");
}

-(void) connectionDidFinishLoading:(NSURLConnection *) connection 
{
    NSLog(@"DONE. Received Bytes: %d", [webData length]);

    NSString *theXML = [[NSString alloc] initWithBytes: [webData mutableBytes] length:[webData length] encoding:NSUTF8StringEncoding];

    //---shows the XML---
    NSLog(@"%@", theXML);  //NOW, THIS IS THE DATA I WANT. BUT HOW CAN I RETURN THIS TO 
                           //THE CALLER. I MEAN, THE CALLER THAT CALLED MY METHOD 
                           //+ (NSData *) dataForMethod: withPostString:
}

Any help here is appreciated! Thanks

Answer 1

实现这一点确实有 2<>m>。

Create a delegate interface

Use Blocks

我强烈建议不要使用同步方法——除非你/自己在周围建立了自己的同步框架(即你正在手工地开始另一条路面,并在此线上执行你的同步要求)。从长远来看,你们会认识到,你们需要成为一席之地,你们必须重新工作一切照样。

2. 迅速概述我提出的两项选择:

1. Create a delegate interface

这里的想法是建立一个履行这一请求的班级,并制定一项议定书,即:eters/em> 必须执行。如申请完成,你将使用代表特定方法提供数据:

议定书可以这样考虑:

@protocol RequestClassDelegate <NSObject> - (void)requestCompleted:(ResponseClass *)data; - (void)requestError:(NSError *)error; @end

提出这一请求的类别可能看起来如此:

@interface RequestClass : NSObject - (void)makeRequest:(id<RequestClassDelegate>)delegate; @end

除您的联系逻辑外,请求类执行还可包含下列内容:

@implementation RequestClass { __weak id<RequestClassDelegate> _delegate; } // Connection Logic, etc. - (void)makeRequest:(id<RequestClassDelegate>)delegate { _delegate = delegate; // Initiate the request... } -(void) connectionDidFinishLoading:(NSURLConnection *) connection { NSString *theXML = [[NSString alloc] initWithBytes: [webData mutableBytes] length:[webData length] encoding:NSUTF8StringEncoding]; // Processing, etc. // Here we ll call the delegate with the result: [_delegate requestCompleted:theResult]; } @end

2. Use Blocks

这一解决办法与第一个解决办法大体相同,但我认为,这种解决办法比以前更合适。在此,我们修改了<代码>RequestClas,以使用区块而不是代表:

typedef void (^requestCompletedBlock)(id); typedef void (^requestErrorBlock)(NSError *); @interface RequestClass : NSObject @property (nonatomic, copy) requestCompletedBlock completed; @property (nonatomic, copy) requestErrorBlock errored; - (void)makeRequest:(requestCompletedBlock)completed error:(requestErrorBlock)error; @end

而执行这一规定可能看起来如此:

@implementation RequestClass @synthesize completed = _completed; @synthesize errored = _errored; // Connection Logic, etc. - (void)makeRequest:(requestCompletedBlock)completed error:(requestErrorBlock)error { self.completed = completed; self.errored = error; // Initiate the request... } -(void) connectionDidFinishLoading:(NSURLConnection *) connection { NSString *theXML = [[NSString alloc] initWithBytes: [webData mutableBytes] length:[webData length] encoding:NSUTF8StringEncoding]; // Processing, etc. // Here we ll call the delegate with the result: self.completed(theResult); } @end

Answer 2

如同你一样,你试图从你的方法中仓促地利用数据回来,但你正在使用一种同步的方法(使用NSURonnection,并大概称其开端方法)来开始检索数据。如果你真的想要你的方法回去,那就会 read忙地阅读。但是,正如@Steve在另一个答复中所说的那样,你也可以重新考虑你的接口设计,而采用不同步的做法加以实施,并用他的建议处理代表或基于集团的接口。

如果你想用你的方法仓促地将数据退回,则使用同步的请求。因此,改变贵国法典的这一部分:

conn = [[NSURLConnection alloc] initWithRequest:req delegate:self];
[conn start]; // I presume you have this somewhere
if (conn) 
{
    webData = [NSMutableData data];
}

更像这一点:

 NSURLResponse *response = nil;
 NSError *error = nil;
 webdata = [NSURLConnection sendSynchronousRequest:req returningResponse:&response error:&error];
 if (webdata) {
     return webdata;
 }
 else {
     // Handle error by looking at response and/or error values
     return nil;
 }

如果你采用这种做法,你将不再需要你的任何代表守则。不过,你在某些方面受到限制。例如,如果贵国的网络服务要求通过“URL”参数以外的手段进行认证,那么你就能够使用这种方法。

Answer 3

Steve的回答是巨大的,我只能建议使用区块的方式。实际上,由于我是新加入目标C,我采用了概述的办法。它完美运作。

The Post for more details and my own point of view you can find here: http://kerkermeister.net/how-to-build-an-cocos2d-ios-app-communicating-with-a-restful-api-the-sequence/

The Post contains all the tiny steps you need to follow to get Steve s solution approach with blocks working. That includes: - an updateable view that will render information as soon as retrieved from Web API asynchronously - a controller invoking the HTTP request to the Web API - the actual HttpRequest class that uses iOS standard NSURLConnections - a model class that uses blocks as callbacks to update its data

Answer 4

Your going to have to either implement a separate method in which you use the data once the data has been returned by the connectionDidFinishLoading method or make the request synchronously. The reason I believe the above does not work is because the request is happening on a separate thread, so the main thread continues, but does not actually have the data.

This is a good way to do that if synchronous is what you want:

所有NSURLConnections的连接都是同步的? iOs

Answer 5

In order to download data from webserivce - use NSURLSession - A URL session task that returns downloaded data directly to the app in memory.

// 1. create NSURL link to your webservice
NSString *dataUrl = @"DATA_LINK_TO_WEBSERVICE";
NSURL *url = [NSURL URLWithString:dataUrl];

// 2. create a NSURLSessionDataTask
NSURLSessionDataTask *downloadTask = [[NSURLSession sharedSession]
  dataTaskWithURL:url completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {
  //Handle response here
}];

// 3.resume the task
[downloadTask resume];

Refernces:

apple documentation refrence: https://developer.apple.com/documentation/foundation/nsurlsessiondatatask?language=objc
Raywanderlich great cookbook: https://www.raywenderlich.com/2392-cookbook-using-nsurlsession

Answer 6

Your going to need to parse the XML that comes back. There are some good Objective C XML parsers out there. One in particular is made for ease of use....

它为摘取你想要的XML的价值观提供了非常轻的权重。我用了很多次,取得了巨大成功,而且没有什么 has。这里是我如何查询网络地址并把它变成数据。

 NSString *query = [NSString stringWithFormat:@"http://WEB_ADDRESS_FOR_XML];
    NSURL *URL = [NSURL URLWithString:query];
    NSData *data = [NSData dataWithContentsOfURL:URL];

或者与NSURLConnection一样,确实收到数据:

-(void) connection:(NSURLConnection *) connection didReceiveData:(NSData *) data 
{
    //USE THE DATA RETURNED HERE....
}

接着,从我的联系中利用Parser来获取内容:

 SMXMLDocument *document = [SMXMLDocument documentWithData:data error:NULL];

    NSLog("
XML Returned:%@",document);

1. Create a delegate interface

2. Use Blocks

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