從NSURLConnection的

Question

沒有響應我有下面的代碼，它應該簡單地加載使用POST數據的URL，然後抓住從服務器的HTML響應：

// Send log in request to server 
NSString *post = [NSString stringWithFormat:@"username=%@&password=%@", text_field_menu_username.text, text_field_menu_password.text]; 
NSData *postData = [post dataUsingEncoding:NSUTF8StringEncoding]; 
NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]]; 
NSMutableURLRequest *request; 
[request setURL:[NSURL URLWithString:@"http://example.com/test.php"]]; // Example Only 
[request setHTTPMethod:@"POST"]; 
[request setValue:postLength forHTTPHeaderField:@"Content-Length"]; 
[request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"]; 
[request setHTTPBody:postData]; 

[NSURLConnection sendAsynchronousRequest:request 
            queue:[NSOperationQueue mainQueue] 
         completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) 
{ 
    // Handle response 
    NSString *response_string = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]; 
    NSLog(@"Data 1: %@", response); 
    NSLog(@"Data 2: %@", data); 
    NSLog(@"Data 3: %@", error); 
    NSLog(@"Data 4: %@", response_string); 
}]; 

下面是每個NSLog的輸出：

Data 1: (null) 
Data 2: (null) 
Data 3: (null) 
Data 4: 

任何想法我做錯了什麼？

Answer 1

在設置其參數之前，您尚未初始化對象request。它應該是：

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];