advice - Bottom navigation handling

Question

I am new in iOS and I have tab bar. I have 4 tabs like Facebook.

In my case all data should be updated from server anytime when user goes one of that screen.

One guy said calling viewDidLoad frequently can make memory leaks. Is that true?

So what's the best play here? Every time call viewDidLoad() and load data from server or there is another way to handle this not calling viewDidLoad() every time.

There is no pull to refresh in that screens

Answer 1

viewDidLoad() will only be called the first time the view controller is loaded. Using a tab bar controller will usually keep the view controllers in memory as the user switches tabs so if you want the loading to occur every time the user goes to a new screen, this is not the best place for it.

I would suggest using viewWillAppear or viewDidAppear. If you're updating data from the network, make sure to do the loading on a background thread to ensure the interface does not get blocked (regardless of which method you use).

Personally I would put network loading code inside viewDidAppear as to me it makes more sense to call the network after the view has finished appearing since it will presumably not finish immediately. This way it is also easier to present a UI element that shows data is loading to the user.