HTTP POST請求iOS問題

Question

所以我收集了此代碼以將POST請求發送到Web服務，但是我一直收到此錯誤

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** +[NSString stringWithUTF8String:]: NULL cString'

我一直在看這是什么意思，但不理解此代碼上下文中的響應。

任何幫助，不勝感激，謝謝

-(IBAction)buttonPressed:(id)sender{

NSString *myRequestString = @"idvar=76";

NSData *myRequestData = [ NSData dataWithBytes: [ myRequestString UTF8String ] length: [ myRequestString length ] ];
NSMutableURLRequest *request = [ [ NSMutableURLRequest alloc ] initWithURL: [ NSURL URLWithString: @"192.168.0.11/test/deleteerrand.php" ] ];
[ request setHTTPMethod: @"POST" ];
[ request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"content-type"];
[ request setHTTPBody: myRequestData ];
NSURLResponse *response;
NSError *err;
NSData *returnData = [ NSURLConnection sendSynchronousRequest: request returningResponse:&response error:&err];
NSString *content = [NSString stringWithUTF8String:[returnData bytes]];
NSLog(@"responseData: %@", content);

}

Answer 1

嘗試這個

NSString *content = [[NSString alloc] initWithData: returnData encoding:NSASCIIStringEncoding];