在TabBarController中使用相同的ViewController和TableView

Question

I have the following problem. I'm using a TabBarController with 5 different tabs for each day from Monday to Friday.

Each tab needs to have only a TableView that display some information depending the current selected tab (aka day).

I'm using for every tab the same ViewController . I'm using the following method

func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController)

to detect the current tab bar index and load the data to display in the table. In my idea this method also updates the variable currentDay which is used to retrieve the correct data to be displayed.

Below the code I use to get such data.

let retrieveOrariofromCoreData = CoreDataController.sharedIstanceCData.load(currentDay)
self.arrayTimes = retrieveOrariofromCoreData
if (self.arrayTimes?.isEmpty)! {
    Utils.setPlaceholderForEmptyTable(self, message: "...")
} else {
    self.tableView.reloadData()
    self.tableView.isHidden = false
}

The problem is that I place this code in the viewDidLoad or viewWillAppear method, which is executed before the tabBarController that changes the variable currentDay .

Maybe my approach is a bit rudimental. I'd like to find a more simple and elegant way to do that.

Answer 1

I don't know when you change your currentDay variable. I have just tested it with UITabBarControllerDelegate s tabBar:didSelect: , which is executed before loading the viewController.

My testing code looks like the following:

var index = 0
override func tabBar(_ tabBar: UITabBar, didSelect item: UITabBarItem) {
    index = (self.tabBar.items?.index(of: item)) ?? 0
}

And then in the viewController in viewDidLoad and viewDidAppear :

print("loaded \((self.tabBarController as? TabViewController)?.index ?? 0)")

which always gave me the correct index.