Here is How You Use the Segmented Control [UISegmentedControl]

A segmented control displays a list of options that a user can choose from. Each segment sort of looks like a button; the segments remains “pressed” even after the user lifts his or her finger.

You can detect when a different segment is selected and also what corresponding value in an array (that you supply) is referenced by the selected segment. Here is an example of what a UISegmentedControl looks like:

Today I can going to show you how to use a segmented control in Objective-C code using the UISegmentedControl class. First thing is a video followed by the written instructions:

Here Are the Steps To Use UISegmentedControl

Create A View Based XCode Project

Add A UILabel To the Controller:

	#import "UseSegmentedControlViewController.h"

	@implementation UseSegmentedControlViewController

	UILabel *label;

	- (void)viewDidLoad {
	    [super viewDidLoad];

		//Create label
		label = [[UILabel alloc] init];
		label.frame = CGRectMake(10, 10, 300, 40);
		label.textAlignment = UITextAlignmentCenter;
		[self.view addSubview:label]; 

	}

	- (void)dealloc {
		[label release];
	    [super dealloc];
	}

	@end

Create An Array:

NSArray *itemArray = [NSArray arrayWithObjects: @"One", @"Two", @"Three", nil];

Create An Instance of UISegmentedControl:

UISegmentedControl *segmentedControl = [[UISegmentedControl alloc] initWithItems:itemArray];

Customize the Control By Setting It’s Properties:

segmentedControl.frame = CGRectMake(35, 200, 250, 50);
segmentedControl.segmentedControlStyle = UISegmentedControlStylePlain;
segmentedControl.selectedSegmentIndex = 1;

Set A Target and Action (The Code That Will Execute When The User Selects A New Segment):

[segmentedControl addTarget:self
                     action:@selector(pickOne:)
           forControlEvents:UIControlEventValueChanged];

Add the Segmented Control to the view:

[self.view addSubview:segmentedControl];
[segmentedControl release];

Implement the Action:

- (void) pickOne:(id)sender{
	UISegmentedControl *segmentedControl = (UISegmentedControl *)sender;
	label.text = [segmentedControl titleForSegmentAtIndex: [segmentedControl selectedSegmentIndex]];
}

Release the UILabel in dealloc:

- (void)dealloc {
	[label release];
	[super dealloc];
}

Here Is the Complete Code For the UIViewController:

//  Segmented Control code originally from Code_Toolbox Bonus Item
//    from the ebook @
//      http://howtomakeaniphoneapp.com
//
#import "UseSegmentedControlViewController.h"

@implementation UseSegmentedControlViewController

UILabel *label;

- (void)viewDidLoad {
	[super viewDidLoad];

	//Create label
	label = [[UILabel alloc] init];
	label.frame = CGRectMake(10, 10, 300, 40);
	label.textAlignment = UITextAlignmentCenter;
	[self.view addSubview:label]; 

	//Create the segmented control
	NSArray *itemArray = [NSArray arrayWithObjects: @"One", @"Two", @"Three", nil];
	UISegmentedControl *segmentedControl = [[UISegmentedControl alloc] initWithItems:itemArray];
	segmentedControl.frame = CGRectMake(35, 200, 250, 50);
	segmentedControl.segmentedControlStyle = UISegmentedControlStylePlain;
	segmentedControl.selectedSegmentIndex = 1;
	[segmentedControl addTarget:self
	                     action:@selector(pickOne:)
	           forControlEvents:UIControlEventValueChanged];
	[self.view addSubview:segmentedControl];
	[segmentedControl release];

}

//Action method executes when user touches the button
- (void) pickOne:(id)sender{
	UISegmentedControl *segmentedControl = (UISegmentedControl *)sender;
	label.text = [segmentedControl titleForSegmentAtIndex: [segmentedControl selectedSegmentIndex]];
} 

- (void)dealloc {
	[label release];
	[super dealloc];
	}

@end

Be Sure To Check Out the Header Files In XCode To See All Your Options

You can change the look and feel of the UISegmentedControl by altering the background color. You can use your own images and add/remove segments on the fly.

What Could You Use UISegmented For In Your App?

Let me know in the comments below. Be sure to link to your apps on iTunes if you have them up yet!

Tagged as: Cocoa-Touch, how to make iphone apps, iPhone Programming, Objective-C, UISegmentedControl, XCode