selectedIndex UItabBarController 不工作

Question

我知道这将是一个简单的解决方案，但由于某种原因，当我尝试使用其他解决方案解决我的问题时，它只是不起作用。在我的应用程序中，我设置了推送通知，并尝试设置从通知打开应用程序时将应用程序打开到某个 tabBarItem 的功能。这是我到目前为止的代码，请告诉我我是否使用了正确的方法。我对AppDelegate.m 不是很有经验，所以如果完全错误，请原谅我。

AppDelegate.m

#import <CoreLocation/CoreLocation.h>

@interface AppDelegate : UIResponder <UIApplicationDelegate,UITabBarControllerDelegate,CLLocationManagerDelegate>{

CLLocationManager *locationManager;
}


@property (strong, nonatomic) UIWindow *window;


@property(nonatomic,readonly) UITabBar *tabBar;
@property(nonatomic,strong) UITabBarController *tabBarController;
@end

AppDelegate.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

UIApplication* app = [UIApplication sharedApplication];
app.networkActivityIndicatorVisible = YES;

[[UIApplication sharedApplication] registerForRemoteNotificationTypes:(UIRemoteNotificationTypeAlert | UIRemoteNotificationTypeBadge |UIRemoteNotificationTypeSound)];


return YES;
}
- (void)application:(UIApplication*)application didReceiveRemoteNotification:(NSDictionary*)userInfo{
/* this works just fine*/
NSLog(@"opening from a notification!!");
/*this is what doesnt work at all*/
self.tabBarController = [[UITabBarController alloc] init];
[self.tabBarController ];
self.tabBarController.selectedIndex = 3;
/*also when i do nslog the selectedIndex it gives me this value "2147483647"*/
NSLog(@"%i is the tabbar item",tabBarController.selectedIndex);
}

Answer 1

因为您从登录控制器推送到标签栏控制器，所以无法从应用委托中获取对标签栏控制器的引用，因为它在被推送之前不存在。我解决这个问题的方法是改变你的应用程序的结构。尽管您当前的结构没有任何问题（因为它会导致崩溃），但我不喜欢将登录控制器放在首位，因为它们仅用于登录一次，那么最好不要使用它们.我会让标签栏控制器成为窗口的根视图控制器，并在第一个标签中通过控制器的 viewDidAppear 方法以模态方式呈现登录控制器，没有动画——这将使登录控制器成为用户看到的第一件事。完成登录后，您只需关闭并返回第一个选项卡。

如果你使用这种结构，那么你可以使用我的建议来设置选定的索引：

- (void)application:(UIApplication*)application didReceiveRemoteNotification:(NSDictionary*)userInfo{
    NSLog(@"opening from a notification!!");
    self.tabBarController = self.window.rootViewController;
    self.tabBarController.selectedIndex = 3;
    NSLog(@"%i is the tabbar item",tabBarController.selectedIndex);
}

Answer 2

对于本地通知：

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
 // it from running if it doesn't exist (such as running under iOS 7 or earlier).
if ([application respondsToSelector:@selector(registerUserNotificationSettings:)]) {
    [application registerUserNotificationSettings:[UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeAlert|UIUserNotificationTypeBadge|UIUserNotificationTypeSound categories:nil]];
}
#endif
[UIApplication sharedApplication].applicationIconBadgeNumber = 0;
if ([UIApplication sharedApplication].scheduledLocalNotifications.count >= 1) {
        // Handle local notification received if app wasn't running in background
        UITabBarController *tabBarController = (UITabBarController *)self.window.rootViewController;
        tabBarController.selectedIndex = 1;
    }else{
    UIViewController *viewController =  [storyboard instantiateViewControllerWithIdentifier:@"tab"];
    self.window.rootViewController = viewController;
    [self.window makeKeyAndVisible];
}
 return YES;
}

对于推送通知：

(1)。

 - (void)application:(UIApplication*)application didReceiveRemoteNotification:(NSDictionary*)userInfo{
NSLog(@"opening from a push/remote notification!!");
  UITabBarController *tabBarController = (UITabBarController *)self.window.rootViewController;
        tabBarController.selectedIndex = 1;
NSLog(@"%i is the tabbar item",tabBarController.selectedIndex);
}

               **(OR).** `

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions{
   int badgeCount = [UIApplication sharedApplication].applicationIconBadgeNumber;
 if (badgeCount >= 1) {
        // Handle local notification received if app wasn't running in background
        UITabBarController *tabBarController = (UITabBarController *)self.window.rootViewController;
        tabBarController.selectedIndex = 1;
    }else{
    UIViewController *viewController =  [storyboard instantiateViewControllerWithIdentifier:@"tab"];
    self.window.rootViewController = viewController;
    [self.window makeKeyAndVisible];
}
self.window.backgroundColor = [UIColor whiteColor];
return YES;
}

`

Answer 3

试试这个

NSUInteger index = [self.tabBarController.tabBar.items indexOfObject:self.tabBarController.tabBar.selectedItem];    
NSLog(@"Index: %d", index);

Answer 4

您应该使用selectedViewController 属性，而不是分配selectedIndex。

self.tabBarController.selectedViewController = [self.tabBarController objectAtIndex:3];//or whatever the index the VC you want to select is

您也不应该从 AppDelegate 分配 tabBarController。您需要获取 rootViewController，然后从那里获取已实例化的 tabBarController 的实例

在此处查看接受的答案，了解如何从 appDelegate 获取 VC 的示例。

How do I access my viewController from my appDelegate? iOS

Answer 5

self.tabBarController = [[UITabBarController alloc]init];
    self.tabBarController.delegate = mobileYakAppDelegate;
    self.tabBarController.viewControllers = ................your view controllers adding here .........;
    self.tabBarController.selectedIndex = 3;
    self.window.rootViewController = mobileYakAppDelegate.tabBarController;  

试试这样对我来说很好用