MainPage.xaml.cs

private async Task GeneratePage()
        {
            List<Folder> folders = await ApiManager.GetFoldersAsync();
            ObservedFoldersList = new ObservableCollection<Folder>(folders);

            // TEMPLATE
            // Make a template for the view
            var template = new DataTemplate(typeof(TextCell));
            // Create a text-field (same as <Label /> in xaml).
            // title is here the property of the class Lists
            template.SetBinding(TextCell.TextProperty, "title");
            // Set a color to the label.
            template.SetValue(TextCell.TextColorProperty, Color.FromHex("#212121"));


            // Make the splashscreen
            ActivityIndicator actInd = new ActivityIndicator
            {
                IsRunning = true,
                IsEnabled = true,
                VerticalOptions = LayoutOptions.Center
            };

            ContentPage loadingPage = new ContentPage
            {
                Content = new Grid
                {
                    Children =
                        {
                            actInd
                        }
                }
            };

            // Generate the page
            this.Children.Add(loadingPage);


            // Loop trough the folders with var f
            foreach (var f in ObservedFoldersList)
            {
                // Make a new List object for the lists in a folder
                List<Lists> lists = new List<Lists>();
                ObservedListsList = new ObservableCollection<Lists>(lists);
                // Loop trough the ID's of the lists
                foreach (int id in f.list_ids)
                {
                    // Add the lists to the lists object using an async link.
                    ObservedListsList.Add(await ApiManager.GetSpecificListAsync(id));
                }

                // listview for the ContentPage
                ListView lvwLists = new ListView
                {
                    ItemsSource = ObservedListsList,
                    SeparatorVisibility = SeparatorVisibility.None,
                    // Here, we specify the template to be used (it's defined above of this) under the 'TEMPLATE' tag.
                    ItemTemplate = template
                };

                Button btn_add_new_list = new Button
                {
                    Text = "Add a new list",
                    BackgroundColor = Color.FromHex("#5b7a59"),
                    TextColor = Color.FromHex("#FAFAFA"),
                    BorderRadius = 0,
                    Margin = new Thickness(20),
                    CommandParameter = f
                };

                // Event listeners
                lvwLists.ItemSelected += LvwLists_ItemSelected;
                btn_add_new_list.Clicked += Btn_add_new_list_Clicked;

                ContentPage page = new ContentPage
                {
                    Title = f.title,
                    Content = new StackLayout
                    {
                        Children =
                        {
                            lvwLists,
                            btn_add_new_list
                        }
                    }
                };

                // Generate the page
                this.Children.Add(page);
            }
            this.Children.Remove(loadingPage);
            actInd.IsRunning = false;
        }