IOS 7 Study - UISegmentedControl

You would like to present a few options to your users from which they can pick an
option, through a UI that is compact, simple, and easy to understand.

effect:

1. declare control

#import "ViewController.h"

@interface ViewController ()

@property (nonatomic, strong) UISegmentedControl *mySegmentedControl;

@end

@implementation ViewController

2. create the segmented control in the viewDidLoad method of your view controller

- (void)viewDidLoad {

  [super viewDidLoad];

  NSArray *segments = [[NSArray alloc] initWithObjects:

        @"iPhone",

        @"iPad",

        @"iPod",

        @"iMac", nil];

  self.mySegmentedControl = [[UISegmentedControl alloc]

                                            initWithItems:segments];

  self.mySegmentedControl.center = self.view.center;

  [self.view addSubview:self.mySegmentedControl];
}

3. use the addTarget:action:forControlEvents: method of the segmented control to

　　recognize when the user selects a new option

// add event listener
[self.mySegmentedControl addTarget:self
action:@selector(segmentChanged:)
forControlEvents:UIControlEventValueChanged];

- (void)viewDidLoad {

  [super viewDidLoad];

  NSArray *segments = @[

    @"iPhone",

    @"iPad",

    @"iPod",

    @"iMac"

  ];

  self.mySegmentedControl = [[UISegmentedControl alloc]

                              initWithItems:segments];

  self.mySegmentedControl.center = self.view.center;

  [self.view addSubview:self.mySegmentedControl];

  [self.mySegmentedControl addTarget:self

         action:@selector(segmentChanged:)

         forControlEvents:UIControlEventValueChanged];

}

4. segment change event

- (void) segmentChanged:(UISegmentedControl *)paramSender {

  if ([paramSender isEqual:self.mySegmentedControl]) {

    NSInteger selectedSegmentIndex = [paramSender   selectedSegmentIndex];

    NSString *selectedSegmentText =

       [paramSender titleForSegmentAtIndex:selectedSegmentIndex];

    NSLog(@"Segment %ld with %@ text is selected",

             (long)selectedSegmentIndex,

              selectedSegmentText);

  }

}

result on console:

Segment 0 with iPhone text is selected
Segment 1 with iPad text is selected
Segment 2 with iPod text is selected
Segment 3 with iMac text is selected

If no item is selected, this method returns the value –1

巴特西

IOS 7 Study - UISegmentedControl

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