情节提要中ViewController的访问属性

Question

     NSString * storyboardName = @"Main";
     UIStoryboard *storyboard = [UIStoryboard storyboardWithName:storyboardName bundle: nil];
     UIViewController * vc = [storyboard instantiateViewControllerWithIdentifier:@"drawingboard"];

I want to access vc.property but the property I want to access in not accessible even though the property is in .h file and has a nonatomic, assign property. Is there anyway I can access that? Please help! Thanks in advance.

Answer 1

The vc must be casted to a specific class which is a subclass of UIViewController .

For instance:

Drawingboard *vc = [storyboard instantiateViewControllerWithIdentifier:@"drawingboard"];

Answer 2

Implement prepareForSegue: method as below:-

Lets say CommentsViewController is the class name of your viewController whom you want to push.

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.

    if ([segue.destinationViewController isKindOfClass:[CommentsViewController class]]) { // Your viewControllerclass 

        CommentsViewController *controller = [segue destinationViewController];
        controller.propertyName = @"Write value here";
    }
}

Answer 3

If you define the property in the .h file than you don't need to redefine it in the .m. Otherwise you'll be accessing the .m object and not the .h property.

    @property (nonatomic) UIViewController *vc;

Above would be your header, below is the implementation

 NSString * storyboardName = @"Main";
 UIStoryboard *storyboard = [UIStoryboard storyboardWithName:storyboardName bundle: nil];
 _vc = [storyboard instantiateViewControllerWithIdentifier:@"drawingboard"];

_vc can also be replaced with self.vc depending on preference but that would be how you access it later on. Hope this Helped