排序HTTP Post請求

Question

我絕對會失去理智。 我有兩個已排序的http帖子調用。 第一個成功返回。 發生這種情況時，將執行第二個調用，但永遠不會返回。 我檢查了一切。 我將我的php腳本簡化為不帶參數的地方，只返回一個字符串。 但是它仍然不會回來。 我是否可以像這樣對HTTP請求進行排序？ 還是我只是想念一些愚蠢的東西？

我已經嘗試了所有我能想到的東西，但是現在變得越來越。 如果無法解決此問題，則我的應用程序已死在水中。 強調幫助請求！！！

這是第一個電話。 這個很好用：

NSString *post = [NSString stringWithFormat:@"&id=%@&password=%@",
                  [[NSUserDefaults standardUserDefaults] objectForKey:@"id"],
                  passwordTextField.text];

NSString *script = @"verifyPassword.php";

MyDownloader *d = [[MyDownloader alloc] initWithPost:post script:script];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(verificationResultsReceived:)
                                             name:@"connectionFinished"
                                           object:d];

[d.connection start];

這是該呼叫的通知方法。

- (void) verificationResultsReceived: (NSNotification *) n
{
    MyDownloader *d = [n object];

    [self.activityIndicator stopAnimating];

    if ([n userInfo]) {
        NSLog(@"information retrieval failed");
    } else {

        NSArray *response = [NSJSONSerialization JSONObjectWithData:d.receivedData options:kNilOptions error:nil];

        if (response) {
            if ([[response valueForKey:@"result"] isEqualToString:@"success"]) {
                // password is verified - OK to update settings
                [self.activityIndicator startAnimating];

                NSString *post = @"";
                NSString *script = @"test.php";
                MyDownloader *d1 = [[MyDownloader alloc] initWithPost:post script:script];

                [[NSNotificationCenter defaultCenter] addObserver:self
                                                         selector:@selector(updateResultsReceived:)
                                                             name:@"connection2Finished"
                                                           object:d1];
                    NSLog(@"I got this far!");
                [d1.connection start];

            } else {
                // incorrect password entered - notify user and halt
                UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Incorrect Password"
                                                                message:@"Invalid password entered. Please try again."
                                                               delegate:self
                                                      cancelButtonTitle:@"OK"
                                                      otherButtonTitles:nil];

                [alert show];
            }

        } else {
            NSLog(@"The server has responded with something other than a JSON formatted object");
        }
    }

    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name: @"connectionFinished"
                                                  object:d];
}

這是下一個通知監視器。 它永遠不會到達這里！ 為什么？？？？

- (void) updateResultsReceived: (NSNotification *) n
{
    NSLog(@"But why don't I see this?");

    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name: @"connection2Finished"
                                                  object:d];
}

如果有幫助，這里是MyDownloader類：

- (id) initWithPost: (NSString *)post
            script : (NSString *)script
{
    self = [super init];

    if (self) {
        self->_mutableReceivedData = [NSMutableData new];

        //Encode the post string using NSASCIIStringEncoding and also the post string you need to send in NSData format.
        NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];

        //You need to send the actual length of your data. Calculate the length of the post string.
        NSString *postLength = [NSString stringWithFormat:@"%lu", (unsigned long)[postData length]];

        //Create a Urlrequest with all the properties like HTTP method, http header field with length of the post string.
        //Create URLRequest object and initialize it.
        self.request = [[NSMutableURLRequest alloc] init];

        // make a string with the url
        NSString *url = [@"http://www.mySite.com/" stringByAppendingString:script];

        // Set the Url for which your going to send the data to that request.
        [self.request setURL:[NSURL URLWithString:url]];

        //Now, set HTTP method (POST or GET).
        [self.request setHTTPMethod:@"POST"];

        //Set HTTP header field with length of the post data.
        [self.request setValue:postLength forHTTPHeaderField:@"Content-Length"];

        //Also set the Encoded value for HTTP header Field.
        [self.request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Current-Type"];

        // Set the HTTPBody of the urlrequest with postData.
        [self.request setHTTPBody:postData];

        self->_connection =
        [[NSURLConnection alloc] initWithRequest:self.request delegate:self startImmediately:NO];

    }

    return self;
}

- (void) connectionDidFinishLoading:(NSURLConnection *) connection
{
    [[NSNotificationCenter defaultCenter]
        postNotificationName:@"connectionFinished" object:self];
}
Thanks for any advice.

Answer 1

不知道您在MyDownloader類中做什么，但是讓我猜。 您創建一個NSURLConnection實例，並在發送通知的地方捕獲其connectionDidFinishLoading 。

您必須記住的一件事是，當您使用initWithRequest創建連接時，它實際上已啟動。

討論區
這等效於調用initWithRequest:delegate:startImmediately:並為startImmediately傳遞YES 。

因此， [d.connection start]; 由於連接已經開始，因此可能不會起作用。 也許在您注冊為觀察者之前它已經回來了！

順便說一句，對於工作者類（例如下載器）而言，首選模式是Singleton Pattern 。 也許您想看看一個類總是知道哪些連接處於活動狀態。