ui分段控制最佳实践

我将使用您提到的第二个选项,在ib中创建子视图,并在主视图中交换它们。这将是一个很好的使用机会 UIViewController ,unbclassed:在初始设置中,使用 -initWithNibName:bundle: (其中第一个参数是包含单个子视图的NIB的名称,第二个参数是 nil 并添加其 view 必要时作为主视图的子视图。这将有助于保持低内存占用:默认的 ui视图控制器 当接收到内存警告时,如果没有超级视图,则释放其视图。只要从视图层次中删除隐藏视图,就可以将控制器保留在内存中,而不必担心释放任何内容。

(根据评论编辑:)

你不需要子类 ui视图控制器 ,但每个视图都需要单独的XIB。您也不需要向ib中的包含视图添加任何内容。

实例变量,在处理所有这一切的任何类的接口中:

 UIViewController *controllerOne;
 UIViewController *controllerTwo;

 UIViewController *currentController;

 IBOutlet UIView *theContainerView;

在你的设置中( -applicationDidFinishLaunching: 或者什么)

 controllerOne = [[UIViewController alloc] initWithNibName:@"MyFirstView" bundle:nil];
 controllerTwo = [[UIViewController alloc] initWithNibName:@"MySecondView" bundle:nil];

切换到控制器:

 - (void)switchToController:(UIViewController *)newCtl
 {
      if(newCtl == currentController)
           return;
      if([currentController isViewLoaded])
           [currentController.view removeFromSuperview];

      if(newCtl != nil)
           [theContainerView addSubview:newCtl.view];

      currentController = newCtl;
 }

那就叫它,例如,

 [self switchToController:controllerOne];

我在iPad应用程序中也遇到了这个需求。

我的解决方案是为 处理与这些视图相关的业务逻辑的每种视图样式 (即与每个段相关),并通过编程将其添加/删除为 响应所选段的“管理”控制器的子视图 指数变化。

为此,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。

下面的代码完成了所有这些工作,同时还考虑了一些注意事项/额外事项:

• viewwill显示/viewwill消失/etc,不在子视图上调用 自动,需要通过“管理”控制器告知
• viewwill appear/viewwill消失/etc,不调用“管理” 当它在导航控制器中时,因此 导航控制器委派
• 如果您想从 段的子视图,您需要重新调用“管理”视图 因为子视图是在 导航层次结构,不会引用导航 控制器。
• 如果在导航控制器方案中使用,返回按钮是 自动设置为段的名称。

接口:

@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

实施:

@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]; // kick everything off
}

- (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

// Required to ensure we call viewDidAppear/viewWillAppear on ourselves (and the active view controller)
// inside of a navigation stack, since viewDidAppear/willAppear insn't invoked automatically. Without this
// selected table views don't know when to de-highlight the selected row.

- (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

希望这有帮助。

下面是一个很好的教程,进一步解释了这个概念: http://redartisan.com/2010/5/26/uisegmented-control-view-switching

以及Github的位置: https://github.com/crafterm/SegmentedControlExample.git