如何:在UITabBarController中自定义选项卡时保存选项卡的顺序

Question

我在查找除了如何保存UITabBarController的Tab键顺序的文档之外的任何其他信息时遇到问题,以便保存用户的自定义以便下次启动应用程序.我在网上搜索过,但一直找不到任何博客文章或文章通过正确的代码来执行此操作.

我意识到我必须使用UITabBarController的委托方法(didEndCustomizingViewControllers :),但我不确定在保存用户想要标签的顺序状态方面我最好如何处理持久性.

有人可以发布一些代码,指出我正确的方向,或者你有一个链接保存的东西？:)

谢谢

Answer 1

至于你已经要求一些示例代码,我将在这里发布我在应用程序中处理相同任务的方式.

快速介绍:我正在使用NIB文件存储初始UITabBarController状态,并且我的选项卡彼此不同我只是为UITabBarItem分配给UIViewController我的每个填充的对象定义了标记变量UITabBarController.为了能够准确地跟踪最后选择的选项卡(包括"更多"之一),我实现以下方法UITabBarControllerDelegate我的UITabBarController和UINavigationControllerDelegate其moreNavigationController的.他们来了:

#pragma mark UINavigationControllerDelegate

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    [[NSUserDefaults standardUserDefaults] setInteger:mainTabBarController.selectedIndex forKey:@"mainTabBarControllerSelectedIndex"];
}

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    [[NSUserDefaults standardUserDefaults] setInteger:mainTabBarController.selectedIndex forKey:@"mainTabBarControllerSelectedIndex"];
}

#pragma mark UITabBarControllerDelegate

- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController {
    [[NSUserDefaults standardUserDefaults] setInteger:tabBarController.selectedIndex forKey:@"mainTabBarControllerSelectedIndex"];
}

这是保存标签顺序的代码:

#pragma mark UITabBarControllerDelegate

- (void)tabBarController:(UITabBarController *)tabBarController didEndCustomizingViewControllers:(NSArray *)viewControllers changed:(BOOL)changed {
    int count = mainTabBarController.viewControllers.count;
    NSMutableArray *savedTabsOrderArray = [[NSMutableArray alloc] initWithCapacity:count];
    for (int i = 0; i < count; i ++) {
        [savedTabsOrderArray addObject:[NSNumber numberWithInt:[[[mainTabBarController.viewControllers objectAtIndex:i] tabBarItem] tag]]];
    }
    [[NSUserDefaults standardUserDefaults] setObject:[NSArray arrayWithArray:savedTabsOrderArray] forKey:@"tabBarTabsOrder"];
    [savedTabsOrderArray release];
}

正如您所看到的,我已经将选项卡索引的顺序存储在数组中NSUserDefaults.

在应用程序的applicationDidFinishLaunching:方法启动时,我UIViewControllers使用以下代码重新排序:

- (void)applicationDidFinishLaunching:(UIApplication *)application {
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    mainTabBarController.delegate = self;

    int count = mainTabBarController.viewControllers.count;
    NSArray *savedTabsOrderArray = [[userDefaults arrayForKey:@"tabBarTabsOrder"] retain];
    if (savedTabsOrderArray.count == count) {
        BOOL needsReordering = NO;

        NSMutableDictionary *tabsOrderDictionary = [[NSMutableDictionary alloc] initWithCapacity:count];
        for (int i = 0; i < count; i ++) {
            NSNumber *tag = [[NSNumber alloc] initWithInt:[[[mainTabBarController.viewControllers objectAtIndex:i] tabBarItem] tag]];
            [tabsOrderDictionary setObject:[NSNumber numberWithInt:i] forKey:[tag stringValue]];

        if (!needsReordering && ![(NSNumber *)[savedTabsOrderArray objectAtIndex:i] isEqualToNumber:tag]) {
                needsReordering = YES;
            }
        }

        if (needsReordering) {
            NSMutableArray *tabsViewControllers = [[NSMutableArray alloc] initWithCapacity:count];
            for (int i = 0; i < count; i ++) {
                [tabsViewControllers addObject:[mainTabBarController.viewControllers objectAtIndex:
                                                [(NSNumber *)[tabsOrderDictionary objectForKey:
                                                              [(NSNumber *)[savedTabsOrderArray objectAtIndex:i] stringValue]] intValue]]];
            }
            [tabsOrderDictionary release];

            mainTabBarController.viewControllers = [NSArray arrayWithArray:tabsViewControllers];
            [tabsViewControllers release];
        }
    }
    [savedTabsOrderArray release];

    if ([userDefaults integerForKey:@"mainTabBarControllerSelectedIndex"]) {
        if ([userDefaults integerForKey:@"mainTabBarControllerSelectedIndex"] == 2147483647) {
            mainTabBarController.selectedViewController = mainTabBarController.moreNavigationController;
        }
        else {
            mainTabBarController.selectedIndex = [userDefaults integerForKey:@"mainTabBarControllerSelectedIndex"];
        }
    }

    mainTabBarController.moreNavigationController.delegate = self;

    [window addSubview:mainTabBarController.view];
}

它非常棘手,可能看起来很奇怪,但不要忘记我UITabBarController是在nib文件中完全创建的.如果您以编程方式构建它,您可能只是按照保存的顺序执行相同操作.

PS:并且不要忘记NSUserDefaults在您的应用终止时进行同步.

- (void)applicationWillTerminate:(UIApplication *)application {
    [[NSUserDefaults standardUserDefaults] synchronize];
}

我希望这将有所帮助.如果不清楚,请做评论并询问.

Answer 2

首先,我投了上一个答案,但后来我注意到它的复杂程度是多么的复杂.它可以而且应该简化.

- (void)applicationDidFinishLaunching:(UIApplication *)application {

    NSArray *initialViewControllers = [NSArray arrayWithArray:self.tabBarController.viewControllers];
    NSArray *tabBarOrder = [[AppDelegate sharedSettingsService] tabBarOrder];
    if (tabBarOrder) {
        NSMutableArray *newViewControllers = [NSMutableArray arrayWithCapacity:initialViewControllers.count];
        for (NSNumber *tabBarNumber in tabBarOrder) {
            NSUInteger tabBarIndex = [tabBarNumber unsignedIntegerValue];
            [newViewControllers addObject:[initialViewControllers objectAtIndex:tabBarIndex]];
        }
        self.tabBarController.viewControllers = newViewControllers;
    }

    NSInteger tabBarSelectedIndex = [[AppDelegate sharedSettingsService] tabBarSelectedIndex];
    if (NSIntegerMax == tabBarSelectedIndex) {
        self.tabBarController.selectedViewController = self.tabBarController.moreNavigationController;
    } else {
        self.tabBarController.selectedIndex = tabBarSelectedIndex;
    }

    /* Add the tab bar controller's current view as a subview of the window. */
    [self.window addSubview:self.tabBarController.view];
}

- (void)applicationWillTerminate:(UIApplication *)application {

    NSInteger tabBarSelectedIndex = self.tabBarController.selectedIndex;
    [[AppDelegate sharedSettingsService] setTabBarSelectedIndex:tabBarSelectedIndex];
    [[NSUserDefaults standardUserDefaults] synchronize];
}

- (void)tabBarController:(UITabBarController *)tabBarController didEndCustomizingViewControllers:(NSArray *)viewControllers changed:(BOOL)changed {

        NSUInteger count = tabBarController.viewControllers.count;
        NSMutableArray *tabOrderArray = [[NSMutableArray alloc] initWithCapacity:count];
        for (UIViewController *viewController in viewControllers) {

            NSInteger tag = viewController.tabBarItem.tag;
            [tabOrderArray addObject:[NSNumber numberWithInteger:tag]];
        }

        [[AppDelegate sharedSettingsService] setTabBarOrder:[NSArray arrayWithArray:tabOrderArray]];
        [tabOrderArray release];
    }

所有这些都发生在AppDelegate中.在Interface Builder中将UITabBarController的委托设置为AppDelegate实例.sharedSettingsService是为我保留数据的原因.基本上它可以是NSUserDefaults前端或任何你喜欢的东西(例如CoreData).所以一切都很简单,Interface Builder在这里有所帮助,而不是让事情变得更复杂.