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iOS

Posted by Kai Aldag
Kai Aldag
Courses Plus Student 13,560 Points

code challenge: tab bar view controller

hey, so I'm on sections 1/2 for the code challenge and it says :We just saw how to change tabs by tapping on them, but we can also do this programmatically using the 'selectedIndex' property of UITabBarController. The tab bar controller in the example below has three tabs. Set the selected tab as the third tab using either dot-notation or the 'setSelectedIndex:' method. Note: The tabs are indexed just like arrays, meaning the first is at index zero. so here my code
#import "MainViewController.h"

import "UITabBarItem.h"

@implementation MainViewController

  • (void)viewDidLoad { [super viewDidLoad];

    NSArray *tabBarItems = self.tabBarController.tabBar.items;

    self.tabBarController.selectedIndex:2; [[tabBarItems selectedIndex:2] badgeValue:[NSString setBadgeValue:@"3"];

}

@end

and i cant get it to work. i read another post and didnt get it but answer and reason would be great.

5 Answers

Michael Reining
Michael Reining
10,101 Points
Michael Reining
Michael Reining
10,101 Points

I was struggling with this too for a while and finally figured it out.

For me, I conceptualized it like this. We need to call a method on an object. The code for that generally looks like this.

[(insert object here) (followed by method)];

We know that the object is: self.tabBarController (this is the object where we want to select the third tab from) We know that the method is setSelectedIndex: We know that to assign it the third tab we go with 2

So the above yields

[self.tabBarController setSelectedIndex:2];
Kai Aldag
PLUS
Kai Aldag
Courses Plus Student 13,560 Points
Kai Aldag
Kai Aldag
Courses Plus Student 13,560 Points

sorry im on part 2 and cant get it

Trevor Gerzen
Trevor Gerzen
2,749 Points
Trevor Gerzen
Trevor Gerzen
2,749 Points

I feel as though I'm missing a few key pieces of information to make this work. Can someone help me on this one?

Mateusz Kaczmarczyk
Mateusz Kaczmarczyk
6,127 Points
Mateusz Kaczmarczyk
Mateusz Kaczmarczyk
6,127 Points

correct solution:
[[tabBarItems objectAtIndex:2] setBadgeValue:@"3"];

James Carney
James Carney
16,255 Points

How did you know that? Was is in the videos or were you on developer.apple website snooping around till you found it?

Kai Aldag
PLUS
Kai Aldag
Courses Plus Student 13,560 Points
Kai Aldag
Kai Aldag
Courses Plus Student 13,560 Points

never mind got it

Brenden Konnagan
Brenden Konnagan
16,858 Points

Hello! I am stuck on this too... is there a clue that you can help me up with?