Add ugly hacky oreo notification support

android/app/src/main/java/de/gotify/PushService.java

@@ -108,6 +108,8 @@ public class PushService extends Service {
         handler = new Handler();
         new Thread(pushService).start();
         appPreferences().registerOnSharedPreferenceChangeListener(listener);
+
+        UglyHackyOreoNotificationCompatibilitySupport.uglyInitializeNotificationChannel((NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE));
     }
 
     private void foregroundNotification(String message) {
@@ -118,6 +120,7 @@ public class PushService extends Service {
         Notification notification = new NotificationCompat.Builder(this, "GOTIFY_CHANNEL")
                 .setSmallIcon(R.mipmap.ic_launcher)
                 .setContentTitle("Gotify")
+                .setChannelId(UglyHackyOreoNotificationCompatibilitySupport.CHANNEL_ID)
                 .setOngoing(true)
                 .setPriority(Notification.PRIORITY_MIN)
                 .setStyle(new NotificationCompat.BigTextStyle().bigText(message))
@@ -286,6 +289,7 @@ public class PushService extends Service {
                 .setContentText(message)
                 .setStyle(new NotificationCompat.BigTextStyle().bigText(message))
                 .setDefaults(Notification.DEFAULT_LIGHTS | Notification.DEFAULT_SOUND)
+                .setChannelId(UglyHackyOreoNotificationCompatibilitySupport.CHANNEL_ID)
                 .setContentIntent(contentIntent);
 
         NotificationManager notificationManager = (NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);

android/app/src/main/java/de/gotify/UglyHackyOreoNotificationCompatibilitySupport.java

@@ -0,0 +1,48 @@
+package de.gotify;
+
+
+import android.app.NotificationManager;
+import android.os.Build;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+
+/**
+ * I hate reflections and android.
+ */
+public class UglyHackyOreoNotificationCompatibilitySupport {
+    public static final String CHANNEL_ID = "gotify";
+
+    /**
+     * @param notificationManager the notification manager
+     * @see <a href="https://stackoverflow.com/a/48861133/4244993">Code by Elad Nava</a>
+     */
+    public static void uglyInitializeNotificationChannel(NotificationManager notificationManager) {
+        if (Build.VERSION.SDK_INT < 26) {
+            return;
+        }
+
+        // Channel importance (3 means default importance)
+        int channelImportance = 3;
+
+        try {
+            // Get NotificationChannel class via reflection (only available on devices running Android O or newer)
+            Class notificationChannelClass = Class.forName("android.app.NotificationChannel");
+
+            // Get NotificationChannel constructor
+            Constructor<?> notificationChannelConstructor = notificationChannelClass.getDeclaredConstructor(String.class, CharSequence.class, int.class);
+
+            // Instantiate new notification channel
+            Object notificationChannel = notificationChannelConstructor.newInstance(CHANNEL_ID, "Gotify", channelImportance);
+
+            // Get notification channel creation method via reflection
+            Method createNotificationChannelMethod = notificationManager.getClass().getDeclaredMethod("createNotificationChannel", notificationChannelClass);
+
+            // Invoke method on NotificationManager, passing in the channel object
+            createNotificationChannelMethod.invoke(notificationManager, notificationChannel);
+
+        } catch (Exception e) {
+            Log.e("Creating notification channel failed.", e);
+        }
+    }
+}