Question

New to iOS dev. Kindly correct me if i am wrong?

I have a UIWindow, and rootviewcontroller is :

@interface ViewController : UIViewController
{
IBOutlet UIButton *but;
}

@property (nonatomic, strong) UIButton  *but;
-(IBAction) butButtonPressed;

@end

ie: If i make this Viewcontroller as a root view controller, the UIView that is available in the ViewController is displayed. Understood.

I have created a new class inherited from UIViewController, and along with its .xib file.

So xib file name is : view1.xib,

My Objective is to display this view when the button is pressed.

Now i have created a button and button press invokes butButtonPressed. Inside of butButtonPressed, i did the following.

  myViewController *vcontroler = [[ViewController alloc] initWithNibName:@"view1" bundle:nil];
    [self.view.window addSubview:vcontroler.view];

Application crashes. What am i doing wrong ? Kindly point out.

Answer 1

This…

[self.view.window addSubview:vcontroler.view];

…is a really bad strategy (and I seriously wish I knew where people are finding it as a way of showing views). If you create a view controller, you should use it rather than just treating it as a temporary container that you can rip views out of.

If you want vcontroler to look like a child of your first controller (and you have a UINavigationController), use pushViewController:animated:. Otherwise you can show it as modal with presentModalViewController:animated:.

If you only want to add a view to the existing display, put the view in ViewController‘s hierarchy and show/hide it.

If you absolutely must have it as a sub-controller of ViewController then you need to keep a reference to it and manage its lifecycle inside the owning controller.