TableviewCell仅在第一次使用didselect方法时花费更多时间

Question

当我选择特定索引处的任何单元格时，我有一个表视图，然后调用didSelectRowAtIndexPath方法

但是每次打开应用程序时第一次需要5到6秒的时间来初始化下一个VC

M没有对下一个vc的viewwillappear进行任何大型处理

我的didselect方法代码：

 func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

        dispatch_async(dispatch_get_main_queue()) { () -> Void in


            let obj: NewService = self.storyboard!.instantiateViewControllerWithIdentifier("AddService") as! NewService
            print("delay 0")
            let casell: Case = self.caseList[indexPath.row]
            print("delay 1")
            obj.caseNo = String(casell.CasesID)
            print("delay 2")
            obj.indexNo = (indexPath.row)
            print("delay 3")
            navigationController!.pushViewController(obj, animated: true)
            print("delay 4")
        }

我的下一个添加服务的vc有这个：

-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    dispatch_async(dispatch_get_main_queue(), ^{

        NSLog(@"delay 5");

        myServiceList = [[NSUserDefaults standardUserDefaults] valueForKey:@"serviceList"];
        alert = [[UIAlertView alloc] init];

        self.txtvwDesc.layer.borderWidth = 0.5f;
        self.txtvwDesc.layer.cornerRadius = 4.0;

        self.txtDate.layer.borderWidth = 0.5f;
        self.txtDate.layer.cornerRadius = 4.0;

        self.txtMinute.layer.borderWidth = 0.5f;
        self.txtMinute.layer.cornerRadius = 4.0;


        self.title = [@"Case No : " stringByAppendingString: self.caseNo];
        // self.title = @"Moin";
        self.btnservice.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;

        [self.txtDate setDropDownMode:IQDropDownModeDatePicker];
        NSLog(@"delay 6");
    });

}