因此，我收集了此代码以向 Web 服务发送 POST 请求，但是我不断收到此错误
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** +[NSString stringWithUTF8String:]: NULL cString'
我已经查看了它的含义，但不理解此代码上下文中的响应。
非常感谢任何帮助，谢谢
-(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);
}