Feat: Add a service system

Once deployed, it will ensure that important jobs don't get killed.

app_pojavlauncher/src/main/AndroidManifest.xml

@@ -4,13 +4,12 @@
     package="net.kdt.pojavlaunch">
 
     <uses-feature android:glEsVersion="0x00020000"/>
-    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
+    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="28"/>
-        android:maxSdkVersion="28"/>
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" android:maxSdkVersion="28"/>
-    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"
-        android:maxSdkVersion="28"/>
     <uses-permission android:name="android.permission.INTERNET"/>
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
     <uses-permission android:name="android.permission.RECORD_AUDIO" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE"/>
 
     <application
         android:process=":launcher"
@@ -121,6 +120,9 @@
 
         </provider>
 
+        <service android:name=".services.LazyService">
+        </service>
+
     </application>
 
 </manifest>

app_pojavlauncher/src/main/java/net/kdt/pojavlaunch/services/LazyService.java

@@ -0,0 +1,86 @@
+package net.kdt.pojavlaunch.services;
+
+import android.app.NotificationChannel;
+import android.app.NotificationManager;
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.os.Build;
+import android.os.IBinder;
+
+import androidx.annotation.Nullable;
+import androidx.core.app.NotificationCompat;
+import androidx.core.app.NotificationManagerCompat;
+import androidx.core.content.ContextCompat;
+
+import net.kdt.pojavlaunch.R;
+
+import java.lang.ref.WeakReference;
+
+/**
+ * Lazy service which allows the process not to get killed.
+ * Can be created from context, can be killed statically
+ */
+public class LazyService extends Service {
+    private static final String NOTIF_TITLE = "notif_title";
+    private static final String NOTIF_DESC = "notif_desc";
+
+    private static WeakReference<Service> sLazyService = new WeakReference<>(null);
+
+    /** Simple wrappers to start the service */
+    public static void startService(Context context){
+        startService(context, R.string.lazy_service_default_title, R.string.lazy_service_default_description);
+    }
+
+    public static void startService(Context context, int titleID, int descriptionID){
+        Intent intent = new Intent(context, LazyService.class);
+        intent.putExtra(NOTIF_TITLE, titleID);
+        intent.putExtra(NOTIF_DESC, descriptionID);
+        ContextCompat.startForegroundService(context, intent);
+    }
+
+
+    /** Kill the service if it is still running */
+    public static void killService(){
+        Service service = sLazyService.get();
+        if(service != null)
+            service.stopSelf();
+    }
+
+    public LazyService(){
+        super();
+        // TODO handle multiple service creation ?
+        sLazyService = new WeakReference<>(this);
+    }
+
+    @Override
+    public int onStartCommand(Intent intent, int flags, int startId) {
+        buildNotificationChannel();
+        //TODO custom strings ?
+        NotificationCompat.Builder builder = new NotificationCompat.Builder(this, "channel_id")
+                .setContentTitle(getString(intent.getIntExtra(NOTIF_TITLE, R.string.lazy_service_default_title)))
+                .setContentText(getString(intent.getIntExtra(NOTIF_DESC ,R.string.lazy_service_default_description)))
+                .setSmallIcon(R.mipmap.ic_launcher_round);
+
+        startForeground(1, builder.build());
+        return super.onStartCommand(intent, flags, startId);
+    }
+
+    @Nullable
+    @Override
+    public IBinder onBind(Intent intent) {
+        return null;
+    }
+
+    private void buildNotificationChannel(){
+        if(Build.VERSION.SDK_INT < Build.VERSION_CODES.O) return;
+
+        NotificationChannel channel = new NotificationChannel(
+                getResources().getString(R.string.notif_channel_id),
+                getResources().getString(R.string.notif_channel_name), NotificationManager.IMPORTANCE_HIGH);
+        NotificationManagerCompat manager = NotificationManagerCompat.from(getApplicationContext());
+
+        manager.createNotificationChannel(channel);
+
+    }
+}