我在iPad应用程序中也遇到了这个要求。
我想到的解决方案是为每种视图创建专门的视图控制器来处理与这些视图相关的业务逻辑(即与每个段相关的逻辑),并在选择段索引更改时以编程方式将它们添加/删除为子视图到一个“管理”控制器中。
要做到这一点,必须创建一个额外的UIViewController子类来管理UISegmentedControl更改,并添加/删除子视图。
下面的代码执行了所有这些操作,还考虑了一些注意事项/附加功能:
- 子视图不会自动调用viewWillAppear / viewWillDisappear等方法,需要通过“管理”控制器告诉它们
- 当“管理”控制器位于导航控制器内部时,它的viewWillAppear / viewWillDisappear等方法不会自动调用,因此需要导航控制器委托
- 如果您想从一个段的子视图推送到导航栈中,您需要回调到“管理”视图来完成操作,因为子视图是在导航层次结构之外创建的,不会有对导航控制器的引用。
- 如果在导航控制器场景中使用,则后退按钮自动设置为段名称。
界面:
@interface SegmentManagingViewController : UIViewController <UINavigationControllerDelegate> {
UISegmentedControl * segmentedControl;
UIViewController * activeViewController;
NSArray * segmentedViewControllers;
}
@property (nonatomic, retain) IBOutlet UISegmentedControl * segmentedControl;
@property (nonatomic, retain) UIViewController * activeViewController;
@property (nonatomic, retain) NSArray * segmentedViewControllers;
@end
实现:
@interface SegmentManagingViewController ()
- (void)didChangeSegmentControl:(UISegmentedControl *)control;
@end
@implementation SegmentManagingViewController
@synthesize segmentedControl, activeViewController, segmentedViewControllers;
- (void)viewDidLoad {
[super viewDidLoad];
UIViewController * controller1 = [[MyViewController1 alloc] initWithParentViewController:self];
UIViewController * controller2 = [[MyViewController2 alloc] initWithParentViewController:self];
UIViewController * controller3 = [[MyViewController3 alloc] initWithParentViewController:self];
self.segmentedViewControllers = [NSArray arrayWithObjects:controller1, controller2, controller3, nil];
[controller1 release];
[controller2 release];
[controller3 release];
self.navigationItem.titleView = self.segmentedControl =
[[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObjects:@"Seg 1", @"Seg 2", @"Seg 3", nil]];
self.segmentedControl.selectedSegmentIndex = 0;
self.segmentedControl.segmentedControlStyle = UISegmentedControlStyleBar;
[self.segmentedControl addTarget:self action:@selector(didChangeSegmentControl:) forControlEvents:UIControlEventValueChanged];
[self didChangeSegmentControl:self.segmentedControl];
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[self.activeViewController viewWillAppear:animated];
}
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[self.activeViewController viewDidAppear:animated];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[self.activeViewController viewWillDisappear:animated];
}
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:animated];
[self.activeViewController viewDidDisappear:animated];
}
#pragma mark -
#pragma mark UINavigationControllerDelegate control
- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
[viewController viewDidAppear:animated];
}
- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
[viewController viewWillAppear:animated];
}
#pragma mark -
#pragma mark Segment control
- (void)didChangeSegmentControl:(UISegmentedControl *)control {
if (self.activeViewController) {
[self.activeViewController viewWillDisappear:NO];
[self.activeViewController.view removeFromSuperview];
[self.activeViewController viewDidDisappear:NO];
}
self.activeViewController = [self.segmentedViewControllers objectAtIndex:control.selectedSegmentIndex];
[self.activeViewController viewWillAppear:NO];
[self.view addSubview:self.activeViewController.view];
[self.activeViewController viewDidAppear:NO];
NSString * segmentTitle = [control titleForSegmentAtIndex:control.selectedSegmentIndex];
self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:segmentTitle style:UIBarButtonItemStylePlain target:nil action:nil];
}
#pragma mark -
#pragma mark Memory management
- (void)dealloc {
self.segmentedControl = nil;
self.segmentedViewControllers = nil;
self.activeViewController = nil;
[super dealloc];
}
@end
希望这可以帮到你。