tabBar property

The tabBar is a CupertinoTabBar drawn at the bottom of the screen that lets the user switch between different tabs in the main content area when present.

Setting and changing CupertinoTabBar.currentIndex programmatically will change the currently selected tab item in the tabBar as well as change the currently focused tab from the tabBuilder. If CupertinoTabBar.onTap is provided, it will still be called. CupertinoTabScaffold automatically also listen to the CupertinoTabBar's onTap to change the CupertinoTabBar's currentIndex and change the actively displayed tab in CupertinoTabScaffold's own main content area.

If translucent, the main content may slide behind it. Otherwise, the main content's bottom margin will be offset by its height.

Must not be null.