Debugging

- [Instructor] So, we have a bug in the app.…Whenever we add a new image, it's there for just a second…and then it disappears.…We can add another one, and the same thing will happen.…And this is because whenever viewWillAppear is called,…it's refreshing the list.…And the first thing it does is empty the list,…then it has to go fetch the images again from the server.…So we need to change that.…Back in the code where we're calling checkSignIn,…we need to do this only once per execution of the app.…And a great place to do that is in viewDidLoad.…

So at the bottom of viewDidLoad, we'll call checkSignIn,…and now it'll only be done once per execution.…And if the user is already signed in,…it'll reload the table, fetching from the server,…otherwise, when we come back from another view,…it won't checkSignIn and it won't refresh.…This'll also save us some performance…from hitting the server,…and any data it uses also will be saved…for not hitting the server and slowing the user down.…So let's run the app again.…And make sure that when we add new items,…