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iOS Build a Self-Destructing Message iPhone App Designing and Starting the App A Storyboard with a Tab Bar Controller

Jake Adam
Jake Adam
9,226 Points
Posted by Jake Adam
Jake Adam
9,226 Points

Designing and Starting the App Code challenge 1/3

I don't understand what the question is asking. I didn't catch him saying anything about this in the video.

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. Use dot-notation or the setSelectedIndex: method to set the 3rd tab as the selected tab. Note: The tabs are indexed just like arrays, meaning the 1st tab is at index 0

MainViewController.m 
#import "MainViewController.h"
#import "UITabBarItem.h"

@implementation MainViewController

- (void)viewDidLoad {
    [super viewDidLoad];

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

    // Add your code below! The property for MainViewController's 
    // tab bar controller is named 'tabBarController'.
   [self.tabBarController.selectedIndex:2];
   }

@end
Caleb Kleveter
Caleb Kleveter
Treehouse Moderator 37,862 Points
Caleb Kleveter
Caleb Kleveter
Treehouse Moderator 37,862 Points

Can you post what the code challenge tells you to do?

Jake Adam
Jake Adam
9,226 Points
Jake Adam
Jake Adam
9,226 Points

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. Use dot-notation or the setSelectedIndex: method to set the 3rd tab as the selected tab. Note: The tabs are indexed just like arrays, meaning the 1st tab is at index 0

1 Answer

Stone Preston
Stone Preston
42,016 Points
Stone Preston
Stone Preston
42,016 Points

right now you have a little mix of dot notation and a regular method call going on. generally using dot notation to set a property looks like

self.someCOntroller.someProperty = someValue;

whereas if you wanted to use a setter method you would use 

[self.someController setSomeProperty:value];

if you wanted to set the property using dot notation you can use

self.tabBarController.selectedIndex = 2;

if you wanted to explicitly use a setter method call you would use:

[self.tabBarController setSelectedIndex:2];

personally I like using dot notation because its less messy and is generally easier to type out

Jake Adam
Jake Adam
9,226 Points
Jake Adam
Jake Adam
9,226 Points

ok thank you