Use startServiceForeground() on Android 8 (fixes #963)

src/main/java/com/nutomic/syncthingandroid/receiver/BatteryReceiver.java

@@ -31,7 +31,7 @@ public class BatteryReceiver extends BroadcastReceiver {
         lbm.sendBroadcast(i);
 
         // Make sure service is running.
-        context.startService(new Intent(context, SyncthingService.class));
+        BootReceiver.startServiceCompat(context);
     }
 
     /**

src/main/java/com/nutomic/syncthingandroid/receiver/BootReceiver.java

@@ -3,6 +3,7 @@ package com.nutomic.syncthingandroid.receiver;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
+import android.os.Build;
 
 import com.nutomic.syncthingandroid.service.SyncthingService;
 
@@ -17,6 +18,21 @@ public class BootReceiver extends BroadcastReceiver {
         if (!SyncthingService.alwaysRunInBackground(context))
             return;
 
-        context.startService(new Intent(context, SyncthingService.class));
+        startServiceCompat(context);
+    }
+
+    /**
+     * Workaround for starting service from background on Android 8.
+     *
+     * https://stackoverflow.com/a/44505719/1837158
+     */
+    public static void startServiceCompat(Context context) {
+        Intent intent = new Intent(context, SyncthingService.class);
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            context.startForegroundService(intent);
+        }
+        else {
+            context.startService(intent);
+        }
     }
 }

src/main/java/com/nutomic/syncthingandroid/receiver/NetworkReceiver.java

@@ -8,7 +8,6 @@ import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 import android.os.Build;
 import android.support.v4.content.LocalBroadcastManager;
-import android.util.Log;
 
 import com.nutomic.syncthingandroid.service.DeviceStateHolder;
 import com.nutomic.syncthingandroid.service.SyncthingService;
@@ -45,7 +44,7 @@ public class NetworkReceiver extends BroadcastReceiver {
         lbm.sendBroadcast(intent);
 
         // Make sure service is running.
-        context.startService(new Intent(context, SyncthingService.class));
+        BootReceiver.startServiceCompat(context);
     }
 
 }

src/main/java/com/nutomic/syncthingandroid/service/NotificationHandler.java

@@ -40,20 +40,31 @@ public class NotificationHandler {
     public void updatePersistentNotification(SyncthingService service, SyncthingService.State currentState) {
         String type = mPreferences.getString(Constants.PREF_NOTIFICATION_TYPE, "low_priority");
         boolean foreground = mPreferences.getBoolean(Constants.PREF_FOREGROUND_SERVICE, false);
+
+        // Android 8 does not allow starting service from background unless it's a foreground
+        // service, so if "always run in background" is enabled, we have to use a foreground service.
+        // https://stackoverflow.com/a/44505719/1837158
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && SyncthingService.alwaysRunInBackground(mContext)) {
+            foreground = true;
+        }
+
+        // foreground priority requires any notification
+        // so this ensures that we either have a "default" or "low_priority" notification,
+        // but not "none".
         if ("none".equals(type) && foreground) {
-            // foreground priority requires any notification
-            // so this ensures that we either have a "default" or "low_priority" notification,
-            // but not "none".
             type = "low_priority";
         }
-        if ((currentState == SyncthingService.State.ACTIVE || currentState == SyncthingService.State.STARTING) &&
-                !type.equals("none")) {
+
+        boolean syncthingRunning = currentState == SyncthingService.State.ACTIVE ||
+                currentState == SyncthingService.State.STARTING;
+        if (foreground || (syncthingRunning && !type.equals("none"))) {
             // Launch FirstStartActivity instead of MainActivity so we can request permission if
             // necessary.
             PendingIntent pi = PendingIntent.getActivity(mContext, 0,
                     new Intent(mContext, FirstStartActivity.class), 0);
+            int title = syncthingRunning ? R.string.syncthing_active : R.string.syncthing_disabled;
             NotificationCompat.Builder builder = new NotificationCompat.Builder(mContext)
-                    .setContentTitle(mContext.getString(R.string.syncthing_active))
+                    .setContentTitle(mContext.getString(title))
                     .setSmallIcon(R.drawable.ic_stat_notify)
                     .setOngoing(true)
                     .setContentIntent(pi);
@@ -74,6 +85,9 @@ public class NotificationHandler {
     }
 
     public void cancelPersistentNotification(SyncthingService service) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && SyncthingService.alwaysRunInBackground(mContext))
+            return;
+
         service.stopForeground(false);
         mNotificationManager.cancel(ID_PERSISTENT);
     }

src/main/java/com/nutomic/syncthingandroid/views/FoldersAdapter.java

@@ -53,6 +53,7 @@ public class FoldersAdapter extends ArrayAdapter<Folder> {
         binding.openFolder.setOnClickListener(v -> {
             Intent intent = new Intent(Intent.ACTION_VIEW);
             intent.setDataAndType(Uri.fromFile(new File(folder.path)), "resource/folder");
+            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
             if (intent.resolveActivity(getContext().getPackageManager()) != null) {
                 getContext().startActivity(intent);
             } else {

src/main/res/values/strings.xml

@@ -519,6 +519,8 @@ Please report any problems you encounter via Github.</string>
     <!-- Title of the notification shown while syncthing is running and enabled -->
     <string name="syncthing_active">Syncthing is running</string>
 
+    <string name="syncthing_disabled">Syncthing is disabled</string>
+
     <string name="syncthing_active_foreground">Service is running with foreground priority.</string>
 
     <!-- Toast shown if folder observer fails to traverse a folder -->