IOSSegmentedControl（添加到Nav上）的简单使用方法

• /* 初始化导航按钮 */  
• {
  
•             credits = [ [ [ UIBarButtonItem alloc ]  
•                         initWithTitle:@"Credits"  
•                         style: UIBarButtonItemStylePlain  
•                         target: appDelegate  
•                         action:@selector(credits) ]  
•                     autorelease ];  
•             self.navigationItem.rightBarButtonItem = credits;  
•  
•             segmentedControl = [ [ UISegmentedControl 
  alloc ] initWithItems: nil ];  
•             segmentedControl.segmentedControlStyle = 
  UISegmentedControlStyleBar;  
•  
•             [ segmentedControl insertSegmentWithTitle: 
  @"Bunnies" atIndex: 0  
•                 animated: NO  
•             ];  
•             [ segmentedControl insertSegmentWithTitle: 
  @"Ponies" atIndex: 1  
•                 animated: NO  
•             ];  
•  
•             [ segmentedControl addTarget: self action: 
  @selector(controlPressed:)  
•                 forControlEvents:UIControlEventValueChanged  
•             ];  
•  
•             self.navigationItem.titleView = segmentedControl;  
•             segmentedControl.selectedSegmentIndex = 0;  
•         }  
•         return self;  
• }  
•  
• - (void)controlPressed:(id) sender {  
•         [ self setPage ];  
• }  
•  
• - (void)setPage {  
•         int index = segmentedControl.selectedSegmentIndex;  
•  
•         if (index == 0) {  
•             textView.text = @"OMG Bunnies!";  
•         } else {  
•             textView.text = @"OMG Ponies";  
•         }  
• }