How to remember last selected tab in UITabBarController?

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小鲜肉
小鲜肉 2021-02-08 04:30

I\'m trying to make my app remember which tab was last being viewed before the app quit, so that the app opens up to the same tab when it is next launched. This is the functiona

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  •  [愿得一人]
    2021-02-08 04:52

    Here's how I did it. Both Methods are in the appDelegate and tabBarController is an instance variable.

    - (void)applicationDidEnterBackground:(UIApplication *)application
    {
        /*
         Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
         If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
         */
    
        //Remember the users last tab selection
        NSInteger tabIndex = self.tabBarController.selectedIndex;
        NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
        [userDefaults setInteger: tabIndex forKey:@"activeTab"];
    
        if (![userDefaults synchronize]) 
        {
            NSLog(@"Error Synchronizing NSUserDefaults");
        }
    
    }
    
    - (void)applicationDidBecomeActive:(UIApplication *)application
    {
        /*
         Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
         */
    
        //Set the tabBarController to the last visted tab
        NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
        int activeTab = [(NSNumber*)[userDefaults objectForKey:@"activeTab"] intValue];
        self.tabBarController.selectedIndex = activeTab;
    }
    

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