Objective-C：线程中的服务器请求（如 Android 中的 AsyncTask）

发布于 2024-10-04 02:02:00 字数 362 浏览 3 评论 0原文

我想发起一个服务器请求，你可以取消。

我的想法是在线程中启动请求，以便用户界面不会冻结。因此，您可以通过单击“取消”按钮来终止包括请求在内的整个线程。

对于 Android，它可以工作：服务器请求在“AsyncTask”中启动，在“onReturn()”方法中，我可以在服务器请求完成后立即做出反应。

我如何在 iOS 上使用 Objective-C 来实现这一点？我的第一次尝试是“NSInitationOperation”。您可以取消操作，但是当请求完成且结果可用时，很难处理。我认为 NSIncationOperation 不是我的问题的解决方案。

你会推荐给我吗？ NSThread 对我来说是正确的选择吗？

非常感谢！

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一杯敬自由 2024-10-11 02:02:00

注意！

这个非常古老的答案现在仅用于历史目的。

精彩的 ASIHttpRequest 库已不复存在；现在的技术已经完全不同了。

使用 ASIHttpRequest 来做到这一点非常简单。

（异步是如此简单，您没有理由非异步地执行它。）

以下是一些可能帮助您入门的粗略摘录。

...
ASIFormDataRequest *request;
...
NSURL *url = [NSURL URLWithString:@"https://blah.blah/blah.cgi?blah"];
request = [ASIFormDataRequest requestWithURL:url];

[request setPostValue:@"fred" forKey:@"username"];
[request setPostValue:@"flint" forKey:@"passie"];
[request setPostValue:@"stone" forKey:@"town"];

// send up data...
[request setData:[NSData dataWithBytes:blah length:blah] forKey:@"thefile"];

// or perhaps something like...
[request setData:imageData withFileName:@"blah.png"
        andContentType:@"image/jpeg" forKey:@"photoimage"];

[request setDelegate:self];
[request setDidFinishSelector:@selector(postingDone:)];
[request setDidFailSelector:@selector(postingDoneProblem:)];
[request startAsynchronous];
...

-(void) postingDone:(ASIHTTPRequest *)request
    {
    // it worked
    }
-(void) postingDoneProblem:(ASIHTTPRequest *)request
    {
    // failed
    }

实在是再简单不过了。您基本上只需键入字段和值即可。

根据您的问题，以下是取消“进行中”请求的方法...只需将委托设置为 nil，然后“取消”它即可。

  [myRequest setDelegate:nil];
  [myRequest cancel];
  [myRequest release];

ASIHttpRequest 是“奇迹库”。如果您是 iOS 新手，ASIHttpRequest 就是最常用的第三方库。本质上，300,000 个 iPhone 应用程序中的每个 iPhone 应用程序都使用它。

如果可能的话，一定要给这个人捐几块钱——如果他停止支持那个库，100,000 名 iPhone 程序员就会被烦死！

该文档很简单，孩子可以理解它：
http://allseeing-i.com/ASIHTTPRequest/How-to-use
“创建异步请求”

它可能（几乎可以肯定）是任何平台上最简单的网络库。做你所描述的事情是微不足道的，快乐。享受。

Note!

This extremely old answer is now here only for historic purposes.

The wonderful ASIHttpRequest library no longer exists; technology is totally different now.

It is unbelievably simple to do this with ASIHttpRequest.

(Asynchronous is so simple, there is no reason you would ever do it not-asynchronously.)

Here are some rough extracts that might get you started.

...
ASIFormDataRequest *request;
...
NSURL *url = [NSURL URLWithString:@"https://blah.blah/blah.cgi?blah"];
request = [ASIFormDataRequest requestWithURL:url];

[request setPostValue:@"fred" forKey:@"username"];
[request setPostValue:@"flint" forKey:@"passie"];
[request setPostValue:@"stone" forKey:@"town"];

// send up data...
[request setData:[NSData dataWithBytes:blah length:blah] forKey:@"thefile"];

// or perhaps something like...
[request setData:imageData withFileName:@"blah.png"
        andContentType:@"image/jpeg" forKey:@"photoimage"];

[request setDelegate:self];
[request setDidFinishSelector:@selector(postingDone:)];
[request setDidFailSelector:@selector(postingDoneProblem:)];
[request startAsynchronous];
...

-(void) postingDone:(ASIHTTPRequest *)request
    {
    // it worked
    }
-(void) postingDoneProblem:(ASIHTTPRequest *)request
    {
    // failed
    }

Couldn't really be any easier. You're basically just typing out the fields and values.

Per your question, here is how you cancel an "in-flight" request... just set the delegate to nil and then "cancel" it.

  [myRequest setDelegate:nil];
  [myRequest cancel];
  [myRequest release];

ASIHttpRequest is the "miracle library". If you are new to iOS, ASIHttpRequest is simply THE most used 3rd party library. Essentially, every single iPhone app of the 300,000 iPhone apps uses it.

If at all possible BE SURE to donate a few bucks to the guy -- if he stops supporting that library, 100,000 iPhone programmers are buggered!

the documentation is trivial, a child can follow it:
http://allseeing-i.com/ASIHTTPRequest/How-to-use
"Creating an asynchronous request"

it is probably - almost certainly - the most amazingly simple networking library on any platform. It is trivial to do what you describe, happily. Enjoy.

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