Activity Indicator not working in Xamarin.Forms - xamarin

Question

I have an activity indicator designed inside a absolute layout. Based on a button click event, I try to show and hide the activity indicator alternatively. But due to some reason, I cannot see my activity Indicator.Any help will be greatly appreciated!!! Thanks in advance.
This is my .xaml.cs class:
public partial class PBTestPage : ContentPage
{
private bool _pbIndicator;
public PBTestPage()
{
InitializeComponent();
}
public bool PBIndicator{
get{
return _pbIndicator;
}set{
_pbIndicator = value;
OnPropertyChanged();
}
}
protected override void OnAppearing()
{
base.OnAppearing();
var parentLayout = new AbsoluteLayout();
var stackContent = new StackLayout();
AbsoluteLayout.SetLayoutFlags(stackContent,AbsoluteLayoutFlags.PositionProportional);
AbsoluteLayout.SetLayoutBounds(stackContent,new Rectangle(0f,0f,AbsoluteLayout.AutoSize,AbsoluteLayout.AutoSize));
var activityIndicator = new ActivityIndicator
{
Color = Color.Black,
IsRunning = PBIndicator,
IsVisible = PBIndicator
};
AbsoluteLayout.SetLayoutFlags(activityIndicator, AbsoluteLayoutFlags.PositionProportional);
AbsoluteLayout.SetLayoutBounds(activityIndicator, new Rectangle(.5, .5, AbsoluteLayout.AutoSize, AbsoluteLayout.AutoSize));
var button = new Button
{
Text="Click",
VerticalOptions=LayoutOptions.CenterAndExpand,
HorizontalOptions=LayoutOptions.CenterAndExpand,
};
button.Clicked += OnClicked;
stackContent.Children.Add(button);
parentLayout.Children.Add(stackContent);
parentLayout.Children.Add(activityIndicator);
Content = parentLayout;
}
private void OnClicked(object sender, EventArgs e)
{
if(PBIndicator==false){
PBIndicator = true;
}else{
PBIndicator = false;
}
}
}

Answer 1

I'm inferring you're intending to use bindings by the use of OnPropertyChanged, so it's a good time to start do it.
I've made some changes in your code and I guess it will work properly now. The changes are:
Moved the layout creation to the constructor (I can't see create the whole same layout on every time the page is shown as a good choice );
The OnClicked event just invert the value of the property, no need to check it before with an if;
Using Bindings to handle the ActivityIndicator's properties state;
Set true to PBIndicator property on the OnAppearing event.
This is the changed code:
public partial class PBTestPage : ContentPage
{
private bool _pbIndicator;
public bool PBIndicator
{
get { return _pbIndicator; }
set
{
_pbIndicator = value;
OnPropertyChanged();
}
}
public PBTestPage()
{
InitializeComponent();
var parentLayout = new AbsoluteLayout();
var stackContent = new StackLayout();
AbsoluteLayout.SetLayoutFlags(stackContent, AbsoluteLayoutFlags.PositionProportional);
AbsoluteLayout.SetLayoutBounds(stackContent, new Rectangle(0f, 0f, AbsoluteLayout.AutoSize, AbsoluteLayout.AutoSize));
var activityIndicator = new ActivityIndicator
{
Color = Color.Black
};
activityIndicator.SetBinding(ActivityIndicator.IsRunningProperty, new Binding(nameof(PBIndicator)));
activityIndicator.SetBinding(ActivityIndicator.IsVisibleProperty, new Binding(nameof(PBIndicator)));
activityIndicator.BindingContext = this;
AbsoluteLayout.SetLayoutFlags(activityIndicator, AbsoluteLayoutFlags.PositionProportional);
AbsoluteLayout.SetLayoutBounds(activityIndicator, new Rectangle(.5, .5, AbsoluteLayout.AutoSize, AbsoluteLayout.AutoSize));
var button = new Button
{
Text = "Click",
VerticalOptions = LayoutOptions.CenterAndExpand,
HorizontalOptions = LayoutOptions.CenterAndExpand,
};
button.Clicked += OnClicked;
stackContent.Children.Add(button);
parentLayout.Children.Add(stackContent);
parentLayout.Children.Add(activityIndicator);
Content = parentLayout;
}
protected override void OnAppearing()
{
base.OnAppearing();
PBIndicator = true;
}
private void OnClicked(object sender, EventArgs e)
{
PBIndicator = !PBIndicator;
}
}
Let me know if it works. I hope it helps.

Answer 2

Try this one
private void OnClicked(object sender, EventArgs e)
{
if(PBIndicator==false){
activityIndicator.IsRunning=true;
}else{
activityIndicator.IsRunning=false;
}
}