[AlternateAppIcons] Add new sample for specifying and using alternate app icons on iOS and tvOS.

AlternateAppIcons/iOS/AlternateAppIcons.csproj

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+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>net9.0-ios</TargetFramework>
+    <OutputType>Exe</OutputType>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>true</ImplicitUsings>
+    <SupportedOSPlatformVersion>13.0</SupportedOSPlatformVersion>
+
+    <!--
+      Enable full trimming in Release mode.
+      To learn more, see: https://learn.microsoft.com/dotnet/core/deploying/trimming/trimming-options#trimming-granularity
+    -->
+    <TrimMode Condition="'$(Configuration)' == 'Release'">full</TrimMode>
+
+    <AppIcon>AppIcon</AppIcon>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <AlternateAppIcon Include="AlternateAppIcons" />
+  </ItemGroup>
+</Project>

AlternateAppIcons/iOS/AppDelegate.cs

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+namespace AlternateAppIcons;
+
+using UserNotifications;
+
+[Register ("AppDelegate")]
+public class AppDelegate : UIApplicationDelegate {
+	UIColor blue = UIColor.FromRGB (81, 43, 212);
+	UIColor green = UIColor.FromRGB (119, 187, 65);
+	UILabel? label;
+	int badgeCount;
+
+	public override UIWindow? Window {
+		get;
+		set;
+	}
+
+	public override bool FinishedLaunching (UIApplication application, NSDictionary launchOptions)
+	{
+		// create a new window instance based on the screen size
+		Window = new UIWindow (UIScreen.MainScreen.Bounds);
+
+		// create a UIViewController with a single UILabel
+		var vc = new UIViewController ();
+
+		var stackView = new UIStackView (Window.Frame);
+		stackView.Axis = UILayoutConstraintAxis.Vertical;
+		stackView.Distribution = UIStackViewDistribution.FillEqually;
+
+		label = new UILabel () {
+			TextColor = blue,
+			TextAlignment = UITextAlignment.Center,
+			Text = "Hello, App Icon Switcher!",
+			AutoresizingMask = UIViewAutoresizing.All,
+		};
+		stackView.AddArrangedSubview (label);
+
+		var primaryIconButton = UIButton.FromType (UIButtonType.RoundedRect);
+		primaryIconButton.SetTitle ("Switch to primary icon", UIControlState.Normal);
+		primaryIconButton.SetTitleColor (blue, UIControlState.Normal);
+		primaryIconButton.TouchUpInside += async (sender, args) => await UsePrimaryIconAsync ();
+		primaryIconButton.Enabled = UIApplication.SharedApplication.SupportsAlternateIcons;
+		stackView.AddArrangedSubview (primaryIconButton);
+
+		var alternateIconButton = UIButton.FromType (UIButtonType.RoundedRect);
+		alternateIconButton.SetTitle ("Switch to alternate icon", UIControlState.Normal);
+		alternateIconButton.SetTitleColor (green, UIControlState.Normal);
+		alternateIconButton.TouchUpInside += async (sender, args) => await UseAlternateIconAsync ();
+		alternateIconButton.Enabled = UIApplication.SharedApplication.SupportsAlternateIcons;
+		stackView.AddArrangedSubview (alternateIconButton);
+
+		var incrementBadgeCount = UIButton.FromType (UIButtonType.RoundedRect);
+		incrementBadgeCount.SetTitle ("Increment badge count", UIControlState.Normal);
+		incrementBadgeCount.PrimaryActionTriggered += (sender, args) => SetBadgeCount (badgeCount + 1);
+		incrementBadgeCount.Enabled = UIApplication.SharedApplication.SupportsAlternateIcons;
+		stackView.AddArrangedSubview (incrementBadgeCount);
+
+		var decrementBadgeCount = UIButton.FromType (UIButtonType.RoundedRect);
+		decrementBadgeCount.SetTitle ("Decrement badge count", UIControlState.Normal);
+		decrementBadgeCount.PrimaryActionTriggered += (sender, args) => SetBadgeCount (badgeCount - 1);
+		decrementBadgeCount.Enabled = UIApplication.SharedApplication.SupportsAlternateIcons;
+		stackView.AddArrangedSubview (decrementBadgeCount);
+
+		vc.View!.AddSubview (stackView);
+		Window.RootViewController = vc;
+
+		// make the window visible
+		Window.MakeKeyAndVisible ();
+
+		return true;
+	}
+
+	void SetBadgeCount (int count)
+	{
+		if (count >= 0) {
+			if (OperatingSystem.IsIOSVersionAtLeast (16, 0)) {
+				UNUserNotificationCenter.Current.RequestAuthorization (UNAuthorizationOptions.Badge, (bool granted, NSError error) => {
+					if (granted) {
+						UNUserNotificationCenter.Current.SetBadgeCount (count, (error) => {
+							InvokeOnMainThread (() => {
+								if (error is null) {
+									label!.Text = $"Updated badge count to {count}";
+									badgeCount = count;
+								} else {
+									label!.Text = $"Updated to update badge count: {error}";
+								}
+							});
+						});
+					} else {
+						InvokeOnMainThread (() => {
+							label!.Text = $"Denied permission to the badge: {error}";
+						});
+					}
+				});
+			} else {
+				UIApplication.SharedApplication.ApplicationIconBadgeNumber = count;
+				badgeCount = count;
+			}
+		} else {
+			label!.Text = $"Can't decrement badge count to below 0.";
+		}
+	}
+
+	async Task UsePrimaryIconAsync ()
+	{
+		label!.Text = $"Switching to primary icon...";
+		try {
+			await UIApplication.SharedApplication.SetAlternateIconNameAsync (null);
+			label!.Text = "Using primary icon";
+			label!.TextColor = blue;
+		} catch (Exception e) {
+			label!.Text = $"Failed to switch to primary icon: {e.Message}";
+			label!.TextColor = UIColor.Red;
+		}
+	}
+
+	async Task UseAlternateIconAsync ()
+	{
+		label!.Text = $"Switching to alternate icon...";
+		try {
+			await UIApplication.SharedApplication.SetAlternateIconNameAsync ("AlternateAppIcons");
+			label!.Text = $"Using alternate icon {UIApplication.SharedApplication.AlternateIconName}";
+			label!.TextColor = green;
+		} catch (Exception e) {
+			label!.Text = $"Failed to switch to alternate icon: {e.Message}";
+			label!.TextColor = UIColor.Red;
+		}
+	}
+}

AlternateAppIcons/iOS/Assets.xcassets/AlternateAppIcons.appiconset/Contents.json

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+{
+  "images": [
+    {
+      "scale": "2x",
+      "size": "20x20",
+      "idiom": "iphone",
+      "filename": "Icon40.png"
+    },
+    {
+      "scale": "3x",
+      "size": "20x20",
+      "idiom": "iphone",
+      "filename": "Icon60.png"
+    },
+    {
+      "scale": "2x",
+      "size": "29x29",
+      "idiom": "iphone",
+      "filename": "Icon58.png"
+    },
+    {
+      "scale": "3x",
+      "size": "29x29",
+      "idiom": "iphone",
+      "filename": "Icon87.png"
+    },
+    {
+      "scale": "2x",
+      "size": "40x40",
+      "idiom": "iphone",
+      "filename": "Icon80.png"
+    },
+    {
+      "scale": "3x",
+      "size": "40x40",
+      "idiom": "iphone",
+      "filename": "Icon120.png"
+    },
+    {
+      "scale": "2x",
+      "size": "60x60",
+      "idiom": "iphone",
+      "filename": "Icon120.png"
+    },
+    {
+      "scale": "3x",
+      "size": "60x60",
+      "idiom": "iphone",
+      "filename": "Icon180.png"
+    },
+    {
+      "scale": "1x",
+      "size": "20x20",
+      "idiom": "ipad",
+      "filename": "Icon20.png"
+    },
+    {
+      "scale": "2x",
+      "size": "20x20",
+      "idiom": "ipad",
+      "filename": "Icon40.png"
+    },
+    {
+      "scale": "1x",
+      "size": "29x29",
+      "idiom": "ipad",
+      "filename": "Icon29.png"
+    },
+    {
+      "scale": "2x",
+      "size": "29x29",
+      "idiom": "ipad",
+      "filename": "Icon58.png"
+    },
+    {
+      "scale": "1x",
+      "size": "40x40",
+      "idiom": "ipad",
+      "filename": "Icon40.png"
+    },
+    {
+      "scale": "2x",
+      "size": "40x40",
+      "idiom": "ipad",
+      "filename": "Icon80.png"
+    },
+    {
+      "scale": "1x",
+      "size": "76x76",
+      "idiom": "ipad",
+      "filename": "Icon76.png"
+    },
+    {
+      "scale": "2x",
+      "size": "76x76",
+      "idiom": "ipad",
+      "filename": "Icon152.png"
+    },
+    {
+      "scale": "2x",
+      "size": "83.5x83.5",
+      "idiom": "ipad",
+      "filename": "Icon167.png"
+    },
+    {
+      "scale": "1x",
+      "size": "1024x1024",
+      "idiom": "ios-marketing",
+      "filename": "Icon1024.png"
+    }
+  ],
+  "properties": {},
+  "info": {
+    "version": 1,
+    "author": "xcode"
+  }
+}

AlternateAppIcons/iOS/Assets.xcassets/AppIcon.appiconset/Contents.json

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+{
+  "images": [
+    {
+      "scale": "2x",
+      "size": "20x20",
+      "idiom": "iphone",
+      "filename": "Icon40.png"
+    },
+    {
+      "scale": "3x",
+      "size": "20x20",
+      "idiom": "iphone",
+      "filename": "Icon60.png"
+    },
+    {
+      "scale": "2x",
+      "size": "29x29",
+      "idiom": "iphone",
+      "filename": "Icon58.png"
+    },
+    {
+      "scale": "3x",
+      "size": "29x29",
+      "idiom": "iphone",
+      "filename": "Icon87.png"
+    },
+    {
+      "scale": "2x",
+      "size": "40x40",
+      "idiom": "iphone",
+      "filename": "Icon80.png"
+    },
+    {
+      "scale": "3x",
+      "size": "40x40",
+      "idiom": "iphone",
+      "filename": "Icon120.png"
+    },
+    {
+      "scale": "2x",
+      "size": "60x60",
+      "idiom": "iphone",
+      "filename": "Icon120.png"
+    },
+    {
+      "scale": "3x",
+      "size": "60x60",
+      "idiom": "iphone",
+      "filename": "Icon180.png"
+    },
+    {
+      "scale": "1x",
+      "size": "20x20",
+      "idiom": "ipad",
+      "filename": "Icon20.png"
+    },
+    {
+      "scale": "2x",
+      "size": "20x20",
+      "idiom": "ipad",
+      "filename": "Icon40.png"
+    },
+    {
+      "scale": "1x",
+      "size": "29x29",
+      "idiom": "ipad",
+      "filename": "Icon29.png"
+    },
+    {
+      "scale": "2x",
+      "size": "29x29",
+      "idiom": "ipad",
+      "filename": "Icon58.png"
+    },
+    {
+      "scale": "1x",
+      "size": "40x40",
+      "idiom": "ipad",
+      "filename": "Icon40.png"
+    },
+    {
+      "scale": "2x",
+      "size": "40x40",
+      "idiom": "ipad",
+      "filename": "Icon80.png"
+    },
+    {
+      "scale": "1x",
+      "size": "76x76",
+      "idiom": "ipad",
+      "filename": "Icon76.png"
+    },
+    {
+      "scale": "2x",
+      "size": "76x76",
+      "idiom": "ipad",
+      "filename": "Icon152.png"
+    },
+    {
+      "scale": "2x",
+      "size": "83.5x83.5",
+      "idiom": "ipad",
+      "filename": "Icon167.png"
+    },
+    {
+      "scale": "1x",
+      "size": "1024x1024",
+      "idiom": "ios-marketing",
+      "filename": "Icon1024.png"
+    }
+  ],
+  "properties": {},
+  "info": {
+    "version": 1,
+    "author": "xcode"
+  }
+}

AlternateAppIcons/iOS/Entitlements.plist

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+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+    <dict>
+    </dict>
+</plist>