Updated StatusBarBehavior to use the NavigatedTo event (#1471)

* Updated StatusBarBehavior to use the NavigatedTo event for setting the color and style and updated the Sample app.

* Added fact to verify expected exception on NavigatedTo event.

* Update src/CommunityToolkit.Maui.UnitTests/Behaviors/StatusBarBehaviorTests.cs

It wasn't inside the if before so forgot to remove it after wrapping it :)

Co-authored-by: Pedro Jesus <[email protected]>

* Removed unit test I do not know how to trigger OnAttachedTo without using reflection.

* Added enum StatusBarApplyOn to control when the StatusBarBehavior applies its configured color and style.

* Updated sample to use the new enum

---------

Co-authored-by: Mikael Nensén <[email protected]>
Co-authored-by: Pedro Jesus <[email protected]>
Co-authored-by: Shaun Lawrence <[email protected]>

samples/CommunityToolkit.Maui.Sample/Pages/Behaviors/BehaviorsGalleryPage.cs

@@ -1,4 +1,5 @@
-using CommunityToolkit.Maui.Sample.ViewModels.Behaviors;
+using CommunityToolkit.Maui.Behaviors;
+using CommunityToolkit.Maui.Sample.ViewModels.Behaviors;
 
 namespace CommunityToolkit.Maui.Sample.Pages.Behaviors;
 
@@ -7,5 +8,18 @@ public class BehaviorsGalleryPage : BaseGalleryPage<BehaviorsGalleryViewModel>
 	public BehaviorsGalleryPage(IDeviceInfo deviceInfo, BehaviorsGalleryViewModel behaviorsGalleryViewModel)
 		: base("Behaviors", deviceInfo, behaviorsGalleryViewModel)
 	{
+#if ANDROID || IOS
+		AddStatusBarBehavior();
+#endif
+	}
+
+	void AddStatusBarBehavior()
+	{
+		Behaviors.Add(new StatusBarBehavior
+		{
+			StatusBarColor = Color.FromRgb(25, 118, 210),
+			StatusBarStyle = Core.StatusBarStyle.LightContent,
+			ApplyOn = StatusBarApplyOn.OnPageNavigatedTo,
+		});
 	}
 }

samples/CommunityToolkit.Maui.Sample/Pages/Behaviors/StatusBarBehaviorPage.xaml

@@ -115,11 +115,10 @@
 
                 <Label Text="Select StatusBar and NavigationBar style" />
 
-                <RadioButton VerticalOptions="Center" IsChecked="{Binding IsDefaultChecked}">
-                    <RadioButton.Content>
-                        <Label Text="Default" Margin="10,0,0,0" VerticalTextAlignment="Center" VerticalOptions="Center" />
-                    </RadioButton.Content>
-                </RadioButton>
+                <RadioButton
+                    Content="Default"
+                    IsChecked="{Binding IsDefaultChecked}"
+                    VerticalOptions="Center" />
 
                 <RadioButton VerticalOptions="Center" IsChecked="{Binding IsLightContentChecked}">
                     <RadioButton.Content>

src/CommunityToolkit.Maui/Behaviors/PlatformBehaviors/StatusBar/StatusBarBehavior.shared.cs

@@ -1,12 +1,27 @@
-
-using System.Runtime.CompilerServices;
+using System.Runtime.CompilerServices;
 using System.Runtime.Versioning;
 using CommunityToolkit.Maui.Core;
 using CommunityToolkit.Maui.Core.Platform;
 using CommunityToolkit.Maui.Extensions;
 
 namespace CommunityToolkit.Maui.Behaviors;
 
+/// <summary>
+/// When to apply the status bar color and style.
+/// </summary>
+public enum StatusBarApplyOn
+{
+	/// <summary>
+	/// Apply color and style when the behavior has been attached to the page.
+	/// </summary>
+	OnBehaviorAttachedTo,
+
+	/// <summary>
+	/// Apply color and style when the page has been navigated to.
+	/// </summary>
+	OnPageNavigatedTo,
+}
+
 /// <summary>
 /// <see cref="PlatformBehavior{TView,TPlatformView}"/> that controls the Status bar color
 /// </summary>
@@ -19,13 +34,18 @@ public class StatusBarBehavior : PlatformBehavior<Page>
 	public static readonly BindableProperty StatusBarColorProperty =
 		BindableProperty.Create(nameof(StatusBarColor), typeof(Color), typeof(StatusBarBehavior), Colors.Transparent);
 
-
 	/// <summary>
 	/// <see cref="BindableProperty"/> that manages the StatusBarColor property.
 	/// </summary>
 	public static readonly BindableProperty StatusBarStyleProperty =
 		BindableProperty.Create(nameof(StatusBarStyle), typeof(StatusBarStyle), typeof(StatusBarBehavior), StatusBarStyle.Default);
 
+	/// <summary>
+	/// <see cref="BindableProperty"/> that manages the ApplyOn property.
+	/// </summary>
+	public static readonly BindableProperty ApplyOnProperty =
+		BindableProperty.Create(nameof(ApplyOn), typeof(StatusBarApplyOn), typeof(StatusBarBehavior), StatusBarApplyOn.OnBehaviorAttachedTo);
+
 	/// <summary>
 	/// Property that holds the value of the Status bar color. 
 	/// </summary>
@@ -44,6 +64,16 @@ public StatusBarStyle StatusBarStyle
 		set => SetValue(StatusBarStyleProperty, value);
 	}
 
+	/// <summary>
+	/// When the status bar color and style should be applied.
+	/// </summary>
+	public StatusBarApplyOn ApplyOn
+	{
+		get => (StatusBarApplyOn)GetValue(ApplyOnProperty);
+		set => SetValue(ApplyOnProperty, value);
+	}
+
+
 #if !(WINDOWS || MACCATALYST || TIZEN)
 
 	/// <inheritdoc /> 
@@ -55,28 +85,49 @@ protected override void OnAttachedTo(Page bindable, Android.Views.View platformV
 	protected override void OnAttachedTo(Page bindable, object platformView)
 #endif
 	{
-		StatusBar.SetColor(StatusBarColor);
-		StatusBar.SetStyle(StatusBarStyle);
+		if (ApplyOn == StatusBarApplyOn.OnBehaviorAttachedTo)
+		{
+			StatusBar.SetColor(StatusBarColor);
+			StatusBar.SetStyle(StatusBarStyle);
+		}
+
+		bindable.NavigatedTo += OnPageNavigatedTo;
 #if IOS
-		bindable.SizeChanged += new EventHandler(page_SizeChanged);
+		bindable.SizeChanged += OnPageSizeChanged;
 #endif
 	}
 
-#if IOS
 	/// <inheritdoc /> 
+#if IOS
 	protected override void OnDetachedFrom(Page bindable, UIKit.UIView platformView)
+#elif ANDROID
+	protected override void OnDetachedFrom(Page bindable, Android.Views.View platformView)
+#else
+	protected override void OnDetachedFrom(Page bindable, object platformView)
+#endif
 	{
-		bindable.SizeChanged -= new EventHandler(page_SizeChanged);
-	}
+#if IOS
+		bindable.SizeChanged -= OnPageSizeChanged;
 #endif
+		bindable.NavigatedTo -= OnPageNavigatedTo;
+	}
 
 #if IOS
-	void page_SizeChanged(object? sender, EventArgs e)
+	void OnPageSizeChanged(object? sender, EventArgs e)
 	{
 		StatusBar.UpdateBarSize();
 	}
 #endif
 
+	void OnPageNavigatedTo(object? sender, NavigatedToEventArgs e)
+	{
+		if (ApplyOn == StatusBarApplyOn.OnPageNavigatedTo)
+		{
+			StatusBar.SetColor(StatusBarColor);
+			StatusBar.SetStyle(StatusBarStyle);
+		}
+	}
+
 	/// <inheritdoc /> 
 	protected override void OnPropertyChanged([CallerMemberName] string? propertyName = null)
 	{