CODEWITHSUNDEEP
objective-c
learningtech
learningtech

Reputation: 33683

In objective C, how do I programmatically access a UIViewController?

Let's say I have a tabbar application that nests a lot of uitableviewcontrollers and uiviewcontrollers. What is the line of code that i would use to get a handle on a particular controller?

For example, let's say I want to grab the uitableviewcontroller which is currently the 3rd tab of the tab bar controller. I am in the MyObject.h/m file which has the following code:

MyObject.h

#import <Foundation/Foundation.h>
#import "MyAppDelegate.h"

@interface MyObject : NSObject

-(void) myfunction;

@end

MyObject.m

#import "MyObject.h"

@implementation MyObject



-(void) myfunction  {

    UITableViewController * mytvc = /*Some line of code*/;

}
@end

What do i replace /*Some line of code*/ with such that mytvc is a variable that points to the uitableviewcontroller i'm interested in?

I am using XCode 4.2. I have a storyboard that illustrates each of my uiviewcontrollers. The Tabbar view controller was the first thing xcode made for me. So I think that means it's the top of the app?

Upvotes: 2

Views: 284

Answers (2)

Jeffery Thomas
Jeffery Thomas

Reputation: 42588

rootViewController.tabBarController.viewControllers is an array of the root view controller for each tab. You can set the active view controller by setting tabBarController.selectedViewController or tabBarController.selectedIndex.

From the app delegate it's self.window.rootViewController.tabBarController. From a view controller it's self.view.window.rootViewController.tabBarController.

[[self.view.window.rootViewController.tabBarController.viewControllers objectAtIndex:2] myFunction] would access your function from another view controller. That is assuming your third tab is not a navigation controller.

If your tab has a navigation controller in it, then you have to add the navigation controller syntax on top of it. [[[self.view.window.rootViewController.tabBarController.viewControllers objectAtIndex:2] navigationController].visibleViewController myFunction] would be the full path. Looking at it now it seems a bit ridiculous.

Upvotes: 1

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726479

If it is your root view controller, and you have access to your app delegate, you should be able to access your controller like this:

appDelegate.window.rootViewController

Upvotes: 1

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