Simplify account notification management

app/src/main/java/eu/faircode/email/ActivitySetup.java

@@ -770,9 +770,9 @@ public class ActivitySetup extends ActivityBilling implements FragmentManager.On
                         account.id = db.account().insertAccount(account);
                         Log.i("Imported account=" + account.name);
 
-                        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O)
-                            if (account.notify)
-                                account.createNotificationChannel(context);
+                        account.deleteNotificationChannel(context);
+                        if (account.notify)
+                            account.createNotificationChannel(context);
 
                         JSONArray jidentities = (JSONArray) jaccount.get("identities");
                         for (int i = 0; i < jidentities.length(); i++) {

app/src/main/java/eu/faircode/email/EntityAccount.java

@@ -23,10 +23,8 @@ import android.app.Notification;
 import android.app.NotificationChannel;
 import android.app.NotificationManager;
 import android.content.Context;
-import android.os.Build;
 
 import androidx.annotation.NonNull;
-import androidx.annotation.RequiresApi;
 import androidx.room.Entity;
 import androidx.room.PrimaryKey;
 
@@ -105,20 +103,22 @@ public class EntityAccount extends EntityOrder implements Serializable {
         return "notification" + (account == 0 ? "" : "." + account);
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.O)
     void createNotificationChannel(Context context) {
-        NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
-        NotificationChannel channel = new NotificationChannel(
-                getNotificationChannelId(id), name,
-                NotificationManager.IMPORTANCE_HIGH);
-        channel.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);
-        nm.createNotificationChannel(channel);
+        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
+            NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+            NotificationChannel channel = new NotificationChannel(
+                    getNotificationChannelId(id), name,
+                    NotificationManager.IMPORTANCE_HIGH);
+            channel.setLockscreenVisibility(Notification.VISIBILITY_PRIVATE);
+            nm.createNotificationChannel(channel);
+        }
     }
 
-    @RequiresApi(api = Build.VERSION_CODES.O)
     void deleteNotificationChannel(Context context) {
-        NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
-        nm.deleteNotificationChannel(getNotificationChannelId(id));
+        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
+            NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+            nm.deleteNotificationChannel(getNotificationChannelId(id));
+        }
     }
 
     @Override

app/src/main/java/eu/faircode/email/FragmentAccount.java

@@ -965,13 +965,10 @@ public class FragmentAccount extends FragmentBase {
                     EntityLog.log(context, (update ? "Updated" : "Added") + " account=" + account.name);
 
                     // Make sure the channel exists on commit
-                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O)
-                        if (account.notify) {
-                            // Add or update notification channel
-                            account.deleteNotificationChannel(context);
-                            account.createNotificationChannel(context);
-                        } else if (!account.synchronize)
-                            account.deleteNotificationChannel(context);
+                    if (account.notify)
+                        account.createNotificationChannel(context);
+                    else if (!account.synchronize)
+                        account.deleteNotificationChannel(context);
 
                     List<EntityFolder> folders = new ArrayList<>();
 

app/src/main/java/eu/faircode/email/ServiceSynchronize.java

@@ -447,11 +447,10 @@ public class ServiceSynchronize extends LifecycleService {
                     // Start monitoring accounts
                     List<EntityAccount> accounts = db.account().getSynchronizingAccounts();
                     for (final EntityAccount account : accounts) {
-                        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O)
-                            if (account.notify)
-                                account.createNotificationChannel(ServiceSynchronize.this);
-                            else
-                                account.deleteNotificationChannel(ServiceSynchronize.this);
+                        if (account.notify)
+                            account.createNotificationChannel(ServiceSynchronize.this);
+                        else
+                            account.deleteNotificationChannel(ServiceSynchronize.this);
 
                         Log.i(account.host + "/" + account.user + " run");
                         final Core.State astate = new Core.State(state);