Question

In my application, I am trying to remove all existing subviews and add a new one created in Interface Builder. However, I don’t seem to be able to connect the view.

When a button clicks, the following function is executed (inside a subclass of UIViewController):

// Display a list of settings to choose from
- (void) settings
{
    SettingsRootController *settingsController = [[SettingsRootController alloc]   initWithNibName:@"SettingsRootController" bundle:nil];
    _settingsController = settingsController;

    for (UIView *view in self.view.subviews) 
    {
        [view removeFromSuperview];
    }

    [self.view addSubview:_settingsController.view2];

    int a = [self.view.subviews count];    
    [self.view setNeedsDisplay];

   ......
}


#import <UIKit/UIKit.h>

@interface SettingsRootController : UIViewController
{
    IBOutlet UIView *_view2;
}

@property(nonatomic, retain) IBOutlet UIView *view2;

Inside the Interface Builder, I created a new View-based xib. Set file owner to SettingsRootController. Randomly drag a UITextView into the xib. Connect the UITextView to view and view2 in SettingsRootController.

However, if the above line is:

[self.view addSubview:_settingsController.view2];

a would always be 0, and thus the new screen is empty.

But if change to:

[self.view addSubview:_settingsController.view];

I could see the UITextView.

Answer 1

When you create a view controller, its view will not be created at initialisation time. The view will be created at first access of the view property. Thats why it works when you use _settingsController.view. But when you access view2 the view will not be loaded. You could write a custom getter method like:

-(UIView*) view2 {
    _view2 = self.view;
    return _view2;
}