在NSRunLoop上，需要进行澄清 [英] On NSRunLoop, clarification needed

问题描述

当我

    Logger *logger = [Logger new];

    NSURL *url = [NSURL URLWithString:@"http://www.google.com"];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];

    __unused NSURLConnection *conn = [[NSURLConnection alloc] 
            initWithRequest:request delegate:logger startImmediately:YES];

...没有任何反应。直到i

... nothing happens. Delegate methods are not called until i

[[NSRunLoop currentRunLoop]run];

我以为 startImmediately：YES 会做到这一点

推荐答案

异步回调需要一个NSRunLoop。见：

async callbacks require an NSRunLoop. See:

可可：NSURLConnection不尝试HTTP请求

命令行应用程序默认情况下没有NSRunLoop - gui apps do。

command line apps don't have an NSRunLoop by default - gui apps do.

从文档中： http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSURLConnection_Class/Reference/Reference.html

initWithRequest：delegate：
返回初始化的URL连接，并开始加载URL请求的数据。

initWithRequest:delegate: Returns an initialized URL connection and begins to load the data for the URL request.

- (id)initWithRequest:(NSURLRequest *)request delegate:(id < NSURLConnectionDelegate >)delegate

...为了使连接正常工作，调用线程的运行
循环必须在默认运行循环模式下运行。请参阅
scheduleInRunLoop：forMode：更改运行循环和模式。

... for the connection to work correctly, the calling thread’s run loop must be operating in the default run loop mode. See scheduleInRunLoop:forMode: to change the run loop and mode.

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