iphone - UISegmentedControl 最佳实践

Question

我正在尝试找出在 iPhone 应用程序中使用 UISegmentedControl 的“最佳”方法。我已经在 stackoverflow 上阅读了一些帖子，并看到了一些人的想法，但我无法完全找出做到这一点的最佳方法。我引用的帖子是:

Changing Views from UISegmentedControl和 How do I use a UISegmentedControl to switch views?

选项似乎是:

• 在 IB 中添加每个 View 并将它们彼此重叠放置，然后显示/隐藏它们
• 在 IB 中单独创建每个 subview ，然后在主视图中创建一个容器以填充您需要的 subview
• 设置一个非常高或非常宽的UIView，并根据所选片段向左/向右或向上/向下设置动画
• 使用 UITabBarController 交换 subview - 看起来很愚蠢
• 对于表格，重新加载表格并在 cellForRowAtIndex 中，根据所选的分段选项从不同的数据源或部分填充表格(我的应用的情况并非如此)

那么哪种方法最适合 subview /非表方法？哪个最容易实现？您能否分享一些该方法的示例代码？

谢谢!

Answer 1

我在 iPad 应用程序中也遇到过这个要求。

我想到的解决方案是创建专门的 View Controller 每种样式的 View 处理与这些 View 相关的业务逻辑(即与每个段相关)，并以编程方式添加/删除它们响应所选段的“管理” Controller 的 subview 索引变化。

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 subview 。

下面的代码完成了这一切，还考虑了一些注意事项/额外的内容:

• viewWillAppear/viewWillDisappear/etc，不会在 subview 上调用自动，并且需要通过“管理” Controller 告知
• viewWillAppear/viewWillDisappear/etc，不会在“管理”时调用 Controller 位于导航 Controller 内时，因此导航 Controller 委托(delegate)
• 如果您想从内部推送到导航堆栈分割的 subview ，您需要回调到“管理” View 这样做，因为 subview 是在外部创建的导航层次结构，并且不会引用导航 Controller 。
• 如果在导航 Controller 场景中使用，则后退按钮为自动设置为段的名称。

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]; // 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。