Listener optimization

app/src/main/java/de/sebse/fuplanner/services/kvv/KVVListener.java

@@ -6,13 +6,13 @@ import de.sebse.fuplanner.services.kvv.types.LoginToken;
 import de.sebse.fuplanner.tools.CustomAccountManager;
 
 public interface KVVListener {
-    void onLogin(LoginToken token);
+    default void onLogin(LoginToken token) {}
 
-    void onLogout();
+    default void onLogout() {}
 
-    void onModuleListChange();
+    default void onModuleListChange() {}
 
-    void onKVVNetworkResponse(NetworkResponse error);
+    default void onKVVNetworkResponse(NetworkResponse error) {}
 
     CustomAccountManager getAccountManager();
 }

app/src/main/java/de/sebse/fuplanner/services/kvv/sync/KVVSyncAdapter.java

@@ -45,29 +45,12 @@ public class KVVSyncAdapter extends AbstractThreadedSyncAdapter {
 
     private void init(Context context) {
         mKVV = new KVV(new KVVListener() {
-            @Override
+            CustomAccountManager accountManager = null;
-            public void onLogin(LoginToken token) {
-
-            }
-
-            @Override
-            public void onLogout() {
-
-            }
-
-            @Override
-            public void onModuleListChange() {
-
-            }
-
-            @Override
-            public void onKVVNetworkResponse(NetworkResponse error) {
-
-            }
-
             @Override
             public CustomAccountManager getAccountManager() {
-                return new CustomAccountManager(AccountManager.get(context), () -> null);
+                if (accountManager == null)
+                    accountManager = new CustomAccountManager(AccountManager.get(context), () -> null);
+                return accountManager;
             }
         }, context);
         mKVV.account().restoreOnlineLogin(bool -> {});