UISegmentedControl within UIView does not respond to change event

Question

I have programmatically created a basic app on iOS7 SDK :

1. Created two UINavigationController
2. Added a view to each of them
3. Created a UITabBarController with two items
4. Added each UINavigationController to its respective UITabBarController

This is working fine, and everything is done programmatically. My project only consists in a simple window app template, without any xib nor storyboard, and everything is done within application didFinishLaunchingWithOptions: of my AppDelegate.m.

I am trying to add a UISegmentedControl (still programmatically) as a subview of the view of the first UINavigationController, as follows :

// First navigation controller
UINavigationController *firstNavController = [[UINavigationController alloc] init];
firstNavController.navigationBar.barTintColor = [UIColor redColor];
firstNavController.title = @"First";
firstNavController.navigationBar.topItem.title = @"First top";
firstNavController.tabBarItem.image = [UIImage imageNamed:@"FirstTab"];

// First view
UIView *firstView = [[UIView alloc] init];
firstView.backgroundColor = [UIColor yellowColor];

// Add a segmented control to this view
UISegmentedControl *segmentedControl = [[UISegmentedControl alloc] initWithItems:
            [NSArray arrayWithObjects:@"One", @"Two", nil]];
// Register an event handler
[segmentedControl addTarget:self action:@selector(segmentedControlSelectedIndexDidChange:)
           forControlEvents:UIControlEventValueChanged];
// Shape it and select its first item
segmentedControl.frame = CGRectMake(10, 100, 300, 20);
segmentedControl.selectedSegmentIndex = 1;

// add the segmented control to the view
[firstView addSubview:segmentedControl];

// and the view to the first tab's navigation controler
[firstNavController.view addSubview:firstView];

The UISegmentedControl DOES show up, but touch events are not handled.

If I change my code and add the UISegmentedControl directly within the UINavigationController, touch events are actually responding :

// and the segmented control directly within the navigation controller
[firstNavController.view addSubview:segmentedControl];

What am I doing wrong, and what should I do to have it respond to it's touch events ?

Answer 1

You need to set the size of the view.

Confusingly a view will be visible even if it is too small to fit it's content but will only respond to touches over the area of it's offical size.

Answer 2

You should not be adding a subview directly to the navigation controllers view.

'firstView' should be encapsulated into a UIViewController. And create your navigation controller with [[UINavigationController alloc] initWithRootViewController:myFirstViewController];