iOS 7 Programming Cookbook

1.2. Creating and Using Switches with UISwitch

Problem

You would like to give your users the ability to turn an option on or off.

Solution

Use the UISwitch class.

Discussion

The UISwitch class provides an On/Off control like the one shown in Figure 1-7 for Auto-Capitalization, Auto-Correction, and so on.

Figure 1-7. UISwitch used in the Settings app on an iPhone

In order to create a switch, you can either use Interface Builder or simply create your instance in code. Let’s do it through code. So next the challenge is to determine which class to place your code in. It needs to be in a View Controller class, which we haven’t discussed yet, but for the single-view application type of app we’re creating in this chapter, you can find the view controller’s .m (implementation) file as ViewController.m. Open that file now.

Let’s create a property of type UISwitch and call it mainSwitch:

#import "ViewController.h"

@interface ViewController ()
@property (nonatomic, strong) UISwitch *mainSwitch;
@end

@implementation ViewController

...

We can go ahead now and create our switch. Find the viewDidLoad method in your view controller’s implementation file:

- (void)viewDidLoad{
  [super viewDidLoad];
}

Let’s create our switch and place it on our view controller’s view:

- (void)viewDidLoad{
  [super viewDidLoad];

  /* Create the switch */
  self.mainSwitch = [[UISwitch alloc] initWithFrame:
                   CGRectMake(100, 100, 0, 0)];