如何实现被杀MAUI关键应用的自动重启？含Android 14适配方案

我原本通过Android前台服务实现应用被杀后的重启逻辑：借助READ_CALL_LOG权限监控日志，发现应用被杀时启动新的Main Activity。但实际测试中遇到两个问题：

• 应用被杀后定时器回调停止工作，无日志输出
• 进程监控显示服务在运行、应用已启动，但界面未在用户桌面显示

问题解决 #

问题根源在于Android 14需要指定前台服务类型。以下是实现后台服务的代码及AndroidManifest.xml配置：

后台服务代码 #

using Android.App;
using Android.Content;
using Android.Content.PM;
using Android.OS;
using Android.Util;
using AndroidX.Core.App;

namespace MauiAppNeverKilled.Platforms.Android;

[Service(Exported = true, ForegroundServiceType = global::Android.Content.PM.ForegroundService.TypeSpecialUse)]
internal class MyBackgroundService : Service
{
    Timer timer = null;
    int myId = new object().GetHashCode();
    int BadgeNumber = 0;
    private readonly IBinder binder = new LocalBinder();
    NotificationCompat.Builder notification;
    //HubConnection hubConnection;

    public class LocalBinder : Binder
    {
        public MyBackgroundService GetService()
        {
            return GetService();
        }
    }

    public override IBinder OnBind(Intent intent)
    {
        return binder;
    }

    public override StartCommandResult OnStartCommand(Intent intent,
        StartCommandFlags flags, int startId)
    {
        var input = intent.GetStringExtra("inputExtra");

        var notificationIntent = new Intent(this, typeof(MainActivity));
        notificationIntent.SetAction("USER_TAPPED_NOTIFIACTION");

        var pendingIntent = PendingIntent.GetActivity(this, 0, notificationIntent,
            PendingIntentFlags.Immutable);

        // 增加通知角标数字
        BadgeNumber++;

        notification = new NotificationCompat.Builder(this,
                MainApplication.ChannelId)
            .SetContentText(input)
            .SetSmallIcon(Resource.Drawable.dotnet_bot)
            .SetAutoCancel(false)
            .SetContentTitle("服务运行中")
            .SetPriority(NotificationCompat.PriorityDefault)
            .SetContentIntent(pendingIntent);

        notification.SetNumber(BadgeNumber);

        // 根据Android版本启动前台服务
        int sdkVersion = (int)Build.VERSION.SdkInt;
        if (Build.VERSION.SdkInt >= BuildVersionCodes.UpsideDownCake)
            StartForeground(myId, notification.Build(), ForegroundService.TypeSpecialUse);
        else
        {
            StartForeground(myId, notification.Build());
        }
        // 定时检查应用是否关闭
        timer = new Timer(Timer_Elapsed, notification, 0, 3000);

        return StartCommandResult.Sticky;
    }

    /// <summary>
    /// 定时器回调方法
    /// </summary>
    /// <param name="state"></param>
    async void Timer_Elapsed(object state)
    {
        AndroidServiceManager.IsRunning = true;

        var activity = Microsoft.Maui.ApplicationModel.Platform.CurrentActivity;

        if(activity == null || activity.IsDestroyed || activity.IsFinishing)
        {
            OpenPackage(package);
        }

        Log.Info("mauneverkilled", $"后台服务定时器 - {DateTime.Now.ToString()}");
    }

    void OpenPackage(string packageName)
    {
        var appScreen = new Intent(this, typeof(MainActivity));
        appScreen.SetFlags(ActivityFlags.NewTask | ActivityFlags.BroughtToFront);
        appScreen.SetAction("START_ACTION");

        appScreen.PutExtra("packageName", packageName);
        this.StartActivity(appScreen);
    }           
}

AndroidManifest.xml配置 #

<uses-permission
   android:name="android.permission.FOREGROUND_SERVICE_SPECIAL_USE"
   android:minSdkVersion="34" />

内容的提问来源于stack exchange，提问作者Vladimir B