NSURLConnectionDelegate - 使用未定义的标识符＆＃39; connection＆＃39;

Question

我是Objective-c的新手所以请耐心等待。我刚从ios中复制并粘贴了关于post请求的教程中的代码，在实现连接方法时我遇到了以下错误： 的 ViewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController <NSURLConnectionDelegate>

@property (weak, nonatomic) IBOutlet UITextField *userNameTextField;
@property (weak, nonatomic) IBOutlet UITextField *passwordTextField;

- (IBAction)postRequest:(id)sender;

@end

ViewController.m

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)postRequest:(id)sender {

    NSString *post = [NSString stringWithFormat:@"Username=%@&Password=%@",@"randomUser",@"randomPassword"];
    NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
    NSString *postLength = [NSString stringWithFormat:@"%lu", [postData length]];

    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    [request setURL:[NSURL URLWithString:[NSString stringWithFormat:@"http:/example.com/users/show.json"]]];
    [request setHTTPMethod:@"POST"];
    [request setValue:postLength forHTTPHeaderField:@"Content-Length"];
    [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
    [request setHTTPBody:postData];
    NSURLConnection * conn = [[NSURLConnection alloc]initWithRequest:request delegate:self];

    if(conn) {
        NSLog(@"Connection Successful");
    } else {
        NSLog(@"Connection could not be made");
    }

    - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
        _responseData = [[NSMutableData alloc] init];
    }


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

    - (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse*)cachedResponse {
        return nil;
    }

    - (void)connectionDidFinishLoading:(NSURLConnection *)connection {
        NSString* respsoneString = [NSString stringWithUTF8String:[_responseData bytes]];
    }

    - (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
        //Do something if there is an error in the connection
    }


}
@end

Answer 1

收到回复是一种NSURLConnectionDataDelegate方法，包括代码中的照片调用

@interface ViewController : UIViewController <NSURLConnectionDelegate, NSURLConnectionDataDelegate>

在您的代码中，您没有关闭上面方法的主体