使用Firebase与.NET MAUI无法修改Android通知背景颜色

算力阿峰

2026-6-19

.NET 8 MAUI Firebase推送通知图标背景异常问题

我在.NET 8 MAUI应用中集成Firebase推送通知，通知可正常接收，但下拉通知栏后，通知图标背景为极浅灰色，导致图标几乎无法辨认。尝试通过AndroidManifest.xml添加配置项解决，但未生效，相关配置代码如下：

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" package="com.mycompany.myapp">
    <application android:icon="@mipmap/appicon">

        <!-- sets the icon, which it is doing correctly. -->
        <meta-data 
            android:name="com.google.firebase.messaging.default_notification_icon"
            android:resource="@drawable/push_notification_icon" />

        <!-- This should set the background color of the icon when you swipe down, 
             but it doesnt seem to work -->
        <meta-data 
            android:name="com.google.firebase.messaging.default_notification_color" 
            android:resource="@color/default_notification_color"
            tools:replace="android:resource" />

        <receiver android:name="com.google.firebase.iid.FirebaseInstanceIdInternalReceiver" android:exported="false" />
        <receiver android:name="com.google.firebase.iid.FirebaseInstanceIdReceiver" android:exported="true" android:permission="com.google.android.c2dm.permission.SEND">
            <intent-filter>
                <action android:name="com.google.android.c2dm.intent.RECEIVE" />
                <action android:name="com.google.android.c2dm.intent.REGISTRATION" />
                <category android:name="${applicationId}" />
            </intent-filter>
        </receiver>
    </application>
    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
</manifest>

Platforms\Android\Resources\values\colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="default_notification_color">#FF0000</color>
</resources>

MauiProgram.cs

using Plugin.Firebase.Auth;
using Plugin.Firebase.Bundled.Shared;

#if IOS
using Plugin.Firebase.Bundled.Platforms.iOS;
#elif ANDROID
using Plugin.Firebase.Bundled.Platforms.Android;
#endif

public static class MauiProgram
{
    public static MauiApp CreateMauiApp()
    {
        return MauiApp
            .CreateBuilder()
            .UseMauiApp<App>()
            .UseMauiCompatibility()
            .UseMauiCommunityToolkit()
            .ConfigureFonts(fonts =>
            {
                fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
                fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");
            })
            .RegisterFirebaseServices()
            .Build();
    }

    private static MauiAppBuilder RegisterFirebaseServices(this MauiAppBuilder builder)
    {
        builder.ConfigureLifecycleEvents(events =>
        {
#if IOS
            events.AddiOS(iOS => iOS.FinishedLaunching((app, launchOptions) => {
                CrossFirebase.Initialize(CreateCrossFirebaseSettings());
                return false;
            }));
#elif ANDROID
            events.AddAndroid(android => android.OnCreate((activity, _) =>
                CrossFirebase.Initialize(activity, CreateCrossFirebaseSettings())
            ));
#endif
        });
        builder.Services.AddSingleton(_ => CrossFirebaseAuth.Current);
        return builder;
    }

    private static CrossFirebaseSettings CreateCrossFirebaseSettings()
    {
        return new CrossFirebaseSettings(
            isAuthEnabled: true,
            isCloudMessagingEnabled: true,
            isAnalyticsEnabled: false);
    }
}

Platforms\Android\MainActivity.cs

using Plugin.Firebase.CloudMessaging;

[Activity(Label = "MyApp", Theme = "@style/Maui.SplashTheme", MainLauncher = true)]
public class MainActivity : MauiAppCompatActivity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        if (OperatingSystem.IsAndroidVersionAtLeast(33))
        {
            if (ContextCompat.CheckSelfPermission(this, Manifest.Permission.PostNotifications) != Permission.Granted)
            {
                ActivityCompat.RequestPermissions(this, new[] { Manifest.Permission.PostNotifications }, 0);
            }
        }

        HandleIntent(Intent);
        CreateNotificationChannelIfNeeded();
    }

    protected override void OnNewIntent(Intent intent)
    {
        base.OnNewIntent(intent);
        HandleIntent(intent);
    }

    private static void HandleIntent(Intent intent)
    {
        FirebaseCloudMessagingImplementation.OnNewIntent(intent);
    }

    private void CreateNotificationChannelIfNeeded()
    {
        if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
        {
            CreateNotificationChannel();
        }
    }

    private void CreateNotificationChannel()
    {
        if (OperatingSystem.IsAndroidVersionAtLeast(26))
        {
            var channelId = $"{PackageName}.general";
            var notificationManager = (NotificationManager)GetSystemService(NotificationService);
            var channel = new NotificationChannel(channelId, "General", NotificationImportance.Default);
            notificationManager.CreateNotificationChannel(channel);
            FirebaseCloudMessagingImplementation.ChannelId = channelId;
            FirebaseCloudMessagingImplementation.SmallIconRef = Resource.Drawable.push_notification_icon;
        }
    }
}

MyApp.csproj

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFrameworks>net8.0-ios;net8.0-android</TargetFrameworks>
    <OutputType>Exe</OutputType>
    <UseMaui>true</UseMaui>
    <!-- lots more here removed -->
  </PropertyGroup>
  
  <ItemGroup>
    <!-- App Icon -->
    <MauiIcon Include="Resources\AppIcon\appicon.png" BaseSize="48,48" Color="#01CAFF" />
    <!-- Images -->
    <MauiImage Include="Resources\Images\*" />
  </ItemGroup>

  <ItemGroup Condition="'$(TargetFramework)' == 'net8.0-android'">
    <GoogleServicesJson Include="Platforms\Android\google-services.json" />
    <PackageReference Include="Xamarin.AndroidX.Core" Version="1.12.0.3" />
    <PackageReference Include="Xamarin.AndroidX.Collection" Version="1.3.0.2" />
    <PackageReference Include="Xamarin.AndroidX.Collection.Ktx" Version="1.3.0.2" />
    <PackageReference Include="Xamarin.AndroidX.Activity.Ktx" Version="1.8.1.1" />
    <PackageReference Include="Xamarin.Google.Android.Material" Version="1.10.0.2" />
  </ItemGroup>
  <ItemGroup>
    <MauiImage Update="Resources\Images\push_notification_icon.png" Resize="false" />
  </ItemGroup>
  <ItemGroup>
    <PackageReference Include="CommunityToolkit.Maui" Version="9.0.3" />
    <PackageReference Include="ExifLib.Standard" Version="1.7.0" />
    <PackageReference Include="Microsoft.Extensions.Http" Version="8.0.0" />
    <PackageReference Include="Microsoft.Extensions.Http.Polly" Version="8.0.8" />
    <PackageReference Include="Microsoft.Extensions.Http.Resilience" Version="8.8.0" />
    <PackageReference Include="Plugin.Firebase" Version="3.0.0" />
    <PackageReference Include="Xamarin.Build.Download" Version="0.11.4" />
  </ItemGroup>

  </ItemGroup>
  <ItemGroup>
    <None Update="Resources\Raw\app_store_logo128x128.png">
      <Pack>True</Pack>
      <PackagePath>\</PackagePath>
    </None>
  </ItemGroup>
</Project>

我已在Firebase控制台创建应用并配置google-services.json，测试通知可正常接收，但图标背景问题未解决。

解决思路

1. 符合Android通知图标规范

Android通知图标要求为透明背景的单色（白色）资源，若push_notification_icon.png不符合：

确保图标背景完全透明
图标主体为白色（系统会根据通知栏主题自动适配颜色）
提供多尺寸适配（如24x24dp、48x48dp等），避免缩放导致的显示问题

2. 为NotificationChannel设置颜色

Android 8.0+的通知栏会使用Channel的颜色作为图标背景，修改CreateNotificationChannel方法，添加颜色配置：

private void CreateNotificationChannel()
{
    if (OperatingSystem.IsAndroidVersionAtLeast(26))
    {
        var channelId = $"{PackageName}.general";
        var notificationManager = (NotificationManager)GetSystemService(NotificationService);
        var channel = new NotificationChannel(channelId, "General", NotificationImportance.Default);
        // 关联自定义颜色资源
        channel.SetColor(ContextCompat.GetColor(this, Resource.Color.default_notification_color));
        notificationManager.CreateNotificationChannel(channel);
        FirebaseCloudMessagingImplementation.ChannelId = channelId;
        FirebaseCloudMessagingImplementation.SmallIconRef = Resource.Drawable.push_notification_icon;
    }
}

3. 验证颜色资源的有效性

确认Platforms\Android\Resources\values\colors.xml的Build Action为AndroidResource
清理项目缓存后重新构建，避免资源未正确打包

4. 处理数据消息的自定义通知

若发送的是Firebase数据消息（而非通知消息），需手动构建通知并设置颜色：

// 示例：处理数据消息时构建通知
var notificationBuilder = new NotificationCompat.Builder(this, channelId)
    .SetSmallIcon(Resource.Drawable.push_notification_icon)
    .SetContentTitle(title)
    .SetContentText(message)
    .SetColor(ContextCompat.GetColor(this, Resource.Color.default_notification_color))
    .SetAutoCancel(true);

NotificationManagerCompat.From(this).Notify(0, notificationBuilder.Build());

5. 适配不同Android版本

Android 7.1及以下：AndroidManifest.xml中的default_notification_color配置生效
Android 8.0+：必须通过NotificationChannel设置颜色，Manifest配置会被Channel覆盖

内容的提问来源于stack exchange，提问作者Mike Luken

使用Firebase与.NET MAUI无法修改Android通知背景颜色

AndroidManifest.xml #

Platforms\Android\Resources\values\colors.xml #

MauiProgram.cs #

Platforms\Android\MainActivity.cs #

MyApp.csproj #

解决思路 #

1. 符合Android通知图标规范 #

2. 为NotificationChannel设置颜色 #

3. 验证颜色资源的有效性 #

4. 处理数据消息的自定义通知 #

5. 适配不同Android版本 #