Xamarin Forms - Changes to ObservableCollection are not updating the View - xaml

Question

I have a ViewModel that, when a Command is executed, gets items from a service and adds those items to an ObservableCollection.
The ObservableCollection is bound to a ListView.
My problem is that adding items to the ObservableCollection is not automatically updating the View - the ListView stays empty. If I call OnPropertyChanged(nameof(ItemList)) then the ListView is updated - but shouldn't the ObservableCollection be taking care of raising this?
I am using the latest Xamarin.Forms (2.3.4.247). This issue only affects Android - if I run on iOS it works correctly.
The ViewModel that implements INotifyPropertyChanged:
public class ListViewModel : ViewModelBase
{
private readonly IService m_Service;
public ListViewModel(IService service)
{
m_Service = service;
ItemList = new ObservableCollection<Item>();
RefreshCommand = new Command(async () => await RefreshData());
}
public ICommand RefreshCommand {get;set;}
public ObservableCollection<Item> ItemList { get; private set; }
private async Task RefreshData()
{
ItemList.Clear();
var newItems = await m_Service.GetItems();
if(newItems != null) {
foreach(var n in newItems)
{
ItemList.Add(new ItemViewModel() { Title = n.Title });
}
}
}
The Item ViewModel (that also implements INotifyPropertyChanged):
public class ItemViewModel : ViewModelBase
{
private string m_JobTitle;
public ItemViewModel()
{
}
public string Title
{
get { return m_Title; }
set
{
m_Title = value;
OnPropertyChanged(nameof(Title));
}
}
}
The 'List' View:
<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:ui="clr-namespace:Test.Mobile.UI;assembly=Test.Mobile.UI"
x:Class="Test.Mobile.UI.MyListView">
<ContentView.Content>
<StackLayout Orientation="Vertical">
<ListView ItemsSource="{Binding ItemList}">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ui:ItemView></ui:ItemView>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</ContentView.Content>
</ContentView>
The 'Item' View:
<?xml version="1.0" encoding="UTF-8"?>
<ContentView xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:enums="clr-namespace:Test.Mobile.Models.Enums;assembly=Test.Mobile.Models"
x:Class="Test.Mobile.UI.JobItemView">
<ContentView.Content>
<Label Text={Binding Title}/>
</ContentView.Content>
</ContentView>

Answer 1

What version of Xamarin Forms are you using?
Update your project to the latest version
If you still having the issue, after adding the all elements try this:
ItemList = new ObservableCollection(newItems);
If that does not work, maybe could be an issue in your ViewModelBase.
For Handle PropertyChanged I use this nice package
https://github.com/Fody/PropertyChanged