从Segue加载视图控制器时调用特定的构造函数

Question

I have added a segue between two view controllers using XCode 6 interface builder. However it calls the default constructor. How can I get it to call a specific constructor for the second view?

view 1 -> click button -> activates segue -> calls constructor of view 2 -> displays view 2 

Answer 1

Using a segue this is unfortunately not possible, you can't further specify how the destinationViewController should be instantiated.

However, instead of using the Storyboard segue, you can instantiate the UIViewController yourself and just push it manually onto the navigation stack.

- (IBAction)buttonTap
{
   ViewController2 *vc2 = <your custom constructor>;
   [self.navigationController pushViewController:vc2 animated:YES]; 
}

(note that this mimics the exact same behaviour that the push segue gives you)

Otherwise, if you want to keep on using the Storyboard segue and your actual goal is to initialize certain properties of ViewController2 , you can implemented prepareForSegue: and set the properties there.

- (void)prepareForSegue:(UIStoryboardSegue *)segue
{
   ViewController2 *vc2 = segue.destinationViewController;
   // set properties here
   vc2.prop = xyz;
}

(note the code is not tested but it should convey the main ideas, let me know if you need further explanation)