NSMutableURLRequest 发送两次

Question

我的 NSMutableURLRequest 向 PHP 发送了两次字符串。我做错了什么？

- (void)viewDidLoad {

// Printando os Dados

/////

NSString *endereco = [[NSString alloc] initWithFormat:@"%@ - CEP: %@", self.sharedData.dataEndereco, self.sharedData.dataCEP];


NSMutableURLRequest *request = 
[[NSMutableURLRequest alloc] initWithURL:
 [NSURL URLWithString:@"http://localhost/dev/mcomm/pedido.php"]];
NSLog(@"ENVI");

[request setHTTPMethod:@"POST"];
NSString *postString = [[NSString alloc] initWithFormat:@"nome=%@&email=%@&endereco=%@&produto=%@&marca=%@&preco=%@&codigo=%@&variacao=%@&parcelas=%@&valorParcelas=%@&cartao=%@&numCartao=%@&codCartao=%@&vencCartao=%@&nomeCartao=%@", self.sharedData.dataNome, self.sharedData.dataEmail, endereco, self.sharedData.dataProd, self.sharedData.dataMarca, self.sharedData.dataPreco, self.sharedData.dataCodigo, self.sharedData.dataVariacao, self.sharedData.numParcelas, self.sharedData.valorParcelas, self.sharedData.cartao, self.sharedData.numeroCartao, self.sharedData.codigoCartao, self.sharedData.dataVencimento, self.sharedData.nomeImpressoCartao];

[request setValue:[NSString 
                   stringWithFormat:@"%d", [postString length]] 
 forHTTPHeaderField:@"Content-length"];

[request setHTTPBody:[postString 
                      dataUsingEncoding:NSUTF8StringEncoding]];

[[NSURLConnection alloc] 
 initWithRequest:request delegate:self];

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
[loaderAtividade startAnimating];


//get response
NSHTTPURLResponse* urlResponse = nil;  
NSError *error = [[NSError alloc] init];  
NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&urlResponse error:&error];  
NSString *result = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];

Answer 1

除了丹尼尔的回答之外，您还可以通过实现 initWithRequest:delegate:startImmediately: with NO 来防止第一个请求触发

NSURLConnection *urlConnection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:NO];

然后稍后，当您想启动异步请求时，只需在连接对象上调用 -start

[urlConnection start];

Answer 2

NSURLConnection *conn = .....
if(conn){
    ......

    [conn cancel];//! important!
    [conn release];
}

停止连接

Answer 3

第一个请求由以下人员发起：

[[NSURLConnection alloc] initWithRequest:request delegate:self];

第二个请求由该函数发送：

 [NSURLConnection sendSynchronousRequest:request returningResponse:&urlResponse error:&error];

注意事项，来自 关于 sendSynchronous 的苹果文档：

重要提示：由于此调用可能需要几分钟才能失败（特别是在 iOS 中使用蜂窝网络时），因此您永远不应该从 GUI 应用程序的主线程调用此函数。

您应该实现 NSURLConnection 委托协议并避免发送同步请求。