Select a tab bar item programmatically (not using UITabBarController)

问题

I have a view derived from UIViewControler (not UITabBarController). In this view I added a tab bar with several tab bar items. I used the UITabBarDelegate to allow the view to do something when users tap on each tab bar item.

class MyViewController: UIViewController, UITabBarDelegate {

    func tabBar(tabBar: UITabBar, didSelectItem item: UITabBarItem!) {
        // do something
    }
}

My question is how we can programmatically select the first tab bar item when the view is first loaded? Note that I would want the first tab item to be in "active" state also.

Again, I'm not using UITabBarController

Thanks

回答1:

[tabBar setSelectedItem: [tabBar.items objectAtIndex:0]];

Which in swift, I think would be:

tabBar.selectedItem = tabBar.items![0] as UITabBarItem

回答2:

Swift 3:

tabBarController.selectedIndex = 0 // (or any other existing index)

回答3:

In swift if tabbar is used not tabbarcontroller set default select

var tabbar:UITabBar?//if declare like this

tabbar!.selectedItem = self.tabbar!.items![0] as? UITabBarItem

or

let tabbar = UITabBar()//if declare and initilize like this

tabbar.selectedItem = self.tabbar.items![0] as? UITabBarItem

回答4:

if you inside UITabBarController you can useself.selectedIndex = // set target index

回答5:

Before select active tab bar item on viewDidLoad event

[self.tabBar setSelectedItem: [self.tabBar.items objectAtIndex:0]];

回答6:

In Xamarin.ios, we can use like this mainTabBarController.selectedIndex=3;

来源：https://stackoverflow.com/questions/29286683/select-a-tab-bar-item-programmatically-not-using-uitabbarcontroller