使用 CommunityToolkit 提供的 StatusBarBehavior 來進行狀態列的顏色變更
這幾天看到這篇 Announcing the .NET MAUI Community Toolkit v1.3 文章，其中看到了 StatusBarBehavior 這個行為可以進行底下的操作
StatusBarColor: allows you to specify the color of the status bar background.
StatusBarStyle: allows you to control if the content (text and icons) on the status bar are light, dark or the system default.
這樣的功能太夢幻了，因為有了他，將不再需要進行實作出原生的程式碼來進行狀態列的背景顏色修正
可是，當我開始使用 Prism.maui 專案範本建立一個專案，根據這篇文章 StatusBarBehavior 的說明，修改專案內的 MainPage.xaml 檔案如下所示
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
xmlns:localBehaviors="clr-namespace:mauiStatusBar.Behaviors"
Title="{Binding Title}"
x:Class="mauiStatusBar.Views.MainPage">
<ContentPage.Behaviors>
<toolkit:StatusBarBehavior StatusBarColor="Fuchsia" StatusBarStyle="LightContent" />
</ContentPage.Behaviors>
<ScrollView>
<VerticalStackLayout
Spacing="25"
Padding="30,0"
VerticalOptions="Center">
<Image Source="prism.png"
SemanticProperties.Description="Cute dot net bot waving hi to you!"
HeightRequest="150"
HorizontalOptions="Center" />
<Label Text="Hello, World!"
SemanticProperties.HeadingLevel="Level1"
FontSize="32"
HorizontalOptions="Center" />
<Label Text="Welcome to Prism for .NET MAUI"
SemanticProperties.HeadingLevel="Level2"
SemanticProperties.Description="Welcome to Prism for dot net Multi platform App U I"
FontSize="18"
HorizontalOptions="Center" />
<Button Text="{Binding Text}"
SemanticProperties.Hint="Counts the number of times you click"
Command="{Binding CountCommand}"
HorizontalOptions="Center" />
</VerticalStackLayout>
</ScrollView>
</ContentPage>想說應該可以很輕鬆的來使用這個功能，沒想到卻得到這樣的錯誤訊息
System.NotImplementedException: 'Either set MainPage or override CreateWindow.'
為了確認我的作法沒有錯誤，我使用原生的 MAUI 專案範本，建立一個原生 MAUI 專案，把上面的做法重新實作一遍，沒想到卻是正常的。
想說，好吧，那麼我把這個 StatusBarBehavior 原始碼找出來，寫到 Prism.Maui 建立起來的專案，直接引用我複製的 StatusBarBehavior 行為，底下是這個 StatusBarBehavior 程式碼
using CommunityToolkit.Maui.Core.Platform;
using CommunityToolkit.Maui.Core;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Runtime.Versioning;
using System.Text;
using System.Threading.Tasks;
namespace mauiStatusBar.Behaviors
{
/// <summary>
/// <see cref="PlatformBehavior{TView,TPlatformView}"/> that controls the Status bar color
/// </summary>
[UnsupportedOSPlatform("Windows"), UnsupportedOSPlatform("MacCatalyst"), UnsupportedOSPlatform("MacOS")]
public class StatusBarBehavior : PlatformBehavior<ContentPage>
{
/// <summary>
/// <see cref="BindableProperty"/> that manages the StatusBarColor property.
/// </summary>
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>
/// Property that holds the value of the Status bar color.
/// </summary>
public Color StatusBarColor
{
get => (Color)GetValue(StatusBarColorProperty);
set => SetValue(StatusBarColorProperty, value);
}
/// <summary>
/// Property that holds the value of the Status bar color.
/// </summary>
public StatusBarStyle StatusBarStyle
{
get => (StatusBarStyle)GetValue(StatusBarStyleProperty);
set => SetValue(StatusBarStyleProperty, value);
}
#if !(WINDOWS || MACCATALYST)
/// <inheritdoc />
#if IOS
protected override void OnAttachedTo(ContentPage bindable, UIKit.UIView platformView)
#elif ANDROID
protected override void OnAttachedTo(ContentPage bindable, Android.Views.View platformView)
#else
protected override void OnAttachedTo(Page bindable, object platformView)
#endif
{
StatusBar.SetColor(StatusBarColor);
StatusBar.SetStyle(StatusBarStyle);
}
/// <inheritdoc />
protected override void OnPropertyChanged([CallerMemberName] string? propertyName = null)
{
if (string.IsNullOrWhiteSpace(propertyName))
{
return;
}
base.OnPropertyChanged(propertyName);
if (IsOneOf(propertyName, StatusBarColorProperty, Page.WidthProperty, Page.HeightProperty))
{
StatusBar.SetColor(StatusBarColor);
}
else if (propertyName == StatusBarStyleProperty.PropertyName)
{
StatusBar.SetStyle(StatusBarStyle);
}
}
#endif
public bool IsOneOf(string propertyName, BindableProperty p0, BindableProperty p1, BindableProperty p2)
{
return propertyName == p0.PropertyName ||
propertyName == p1.PropertyName ||
propertyName == p2.PropertyName;
}
}
}天不從人願，還是得到一樣的錯誤訊息，現在只好到 PrismLibrary / Prism.Maui 發出一個 Issue，也許是我有贊助這個開源專案，所以很快地得到作者的回應，不過，看樣子不是那麼容易的來解決這個問題。
經過幾天的陸續測試與思考，我想到一個做法，我想要在 MainPage 的覆寫方法 OnAppearing 內，直接呼叫這個 CommunityToolkit 所提供的 StatusBar.SetColor 這個方法，不知道是否可以解決這個問題呢？
因此，我將原來的 MainPage.xaml 修改如下
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:toolkit="http://schemas.microsoft.com/dotnet/2022/maui/toolkit"
xmlns:localBehaviors="clr-namespace:mauiStatusBar.Behaviors"
Title="{Binding Title}"
x:Class="mauiStatusBar.Views.MainPage">
<!--<ContentPage.Behaviors>
<toolkit:StatusBarBehavior StatusBarColor="Fuchsia" StatusBarStyle="LightContent" />
</ContentPage.Behaviors>-->
<ScrollView>
<VerticalStackLayout
Spacing="25"
Padding="30,0"
VerticalOptions="Center">
<Image Source="prism.png"
SemanticProperties.Description="Cute dot net bot waving hi to you!"
HeightRequest="150"
HorizontalOptions="Center" />
<Label Text="Hello, World!"
SemanticProperties.HeadingLevel="Level1"
FontSize="32"
HorizontalOptions="Center" />
<Label Text="Welcome to Prism for .NET MAUI"
SemanticProperties.HeadingLevel="Level2"
SemanticProperties.Description="Welcome to Prism for dot net Multi platform App U I"
FontSize="18"
HorizontalOptions="Center" />
<Button Text="{Binding Text}"
SemanticProperties.Hint="Counts the number of times you click"
Command="{Binding CountCommand}"
HorizontalOptions="Center" />
</VerticalStackLayout>
</ScrollView>
</ContentPage>我不再使用 Behavior 來變更狀態列的顏色，接著，在這個頁面的 Code Behind 內，改成底下的程式碼
using CommunityToolkit.Maui.Core.Platform;
namespace mauiStatusBar.Views;
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
}
protected override void OnAppearing()
{
var foo = App.Current.MainPage;
StatusBar.SetColor(Colors.Red);
}
}並且執行這個 Android 專案，得到底下的結果
太好了，這樣的作法是可行的
