Lazily init EventBus

app/src/main/java/dummydomain/yetanothercallblocker/App.java

@@ -5,8 +5,6 @@ import android.app.Application;
 import android.content.Context;
 import android.os.Build;
 
-import org.greenrobot.eventbus.EventBus;
-
 import dummydomain.yetanothercallblocker.data.Config;
 
 public class App extends Application {
@@ -35,14 +33,6 @@ public class App extends Application {
         settings = new Settings(getDeviceProtectedStorageContext());
         settings.init();
 
-        EventBus.builder()
-                .throwSubscriberException(BuildConfig.DEBUG)
-                .sendNoSubscriberEvent(false)
-                .addIndex(new EventBusIndex())
-                .installDefaultEventBus();
-
-        EventHandler.create(this);
-
         Config.init(getDeviceProtectedStorageContext(), settings);
     }
 

app/src/main/java/dummydomain/yetanothercallblocker/DebugActivity.java

@@ -9,7 +9,6 @@ import android.widget.TextView;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.core.util.Pair;
 
-import org.greenrobot.eventbus.EventBus;
 import org.greenrobot.eventbus.Subscribe;
 import org.greenrobot.eventbus.ThreadMode;
 
@@ -41,12 +40,12 @@ public class DebugActivity extends AppCompatActivity {
     protected void onStart() {
         super.onStart();
 
-        EventBus.getDefault().register(this);
+        EventUtils.register(this);
     }
 
     @Override
     protected void onStop() {
-        EventBus.getDefault().unregister(this);
+        EventUtils.unregister(this);
 
         super.onStop();
     }

app/src/main/java/dummydomain/yetanothercallblocker/EventHandler.java

@@ -1,38 +0,0 @@
-package dummydomain.yetanothercallblocker;
-
-import android.annotation.SuppressLint;
-import android.content.Context;
-
-import org.greenrobot.eventbus.EventBus;
-import org.greenrobot.eventbus.Subscribe;
-import org.greenrobot.eventbus.SubscriberExceptionEvent;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-public class EventHandler {
-
-    private static final Logger LOG = LoggerFactory.getLogger(EventHandler.class);
-
-    @SuppressLint("StaticFieldLeak") // same lifecycle
-    private static EventHandler instance;
-
-    private Context context;
-
-    public static EventHandler create(Context context) {
-        EventHandler instance = new EventHandler(context);
-
-        EventBus.getDefault().register(instance);
-
-        return EventHandler.instance = instance;
-    }
-
-    private EventHandler(Context context) {
-        this.context = context;
-    }
-
-    @Subscribe
-    public void onSubscriberExceptionEvent(SubscriberExceptionEvent event) {
-        LOG.warn("onSubscriberExceptionEvent()", event.throwable);
-    }
-
-}

app/src/main/java/dummydomain/yetanothercallblocker/EventUtils.java

@@ -1,9 +1,33 @@
 package dummydomain.yetanothercallblocker;
 
 import org.greenrobot.eventbus.EventBus;
+import org.greenrobot.eventbus.Subscribe;
+import org.greenrobot.eventbus.SubscriberExceptionEvent;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class EventUtils {
 
+    private static final Logger LOG = LoggerFactory.getLogger(EventUtils.class);
+
+    private static EventUtils instance;
+
+    private static class Holder {
+        static final EventBus bus = createBus();
+    }
+
+    public static EventBus bus() {
+        return Holder.bus;
+    }
+
+    public static void register(Object subscriber) {
+        bus().register(subscriber);
+    }
+
+    public static void unregister(Object subscriber) {
+        bus().unregister(subscriber);
+    }
+
     public static void postEvent(Object event) {
         bus().post(event);
     }
@@ -16,8 +40,24 @@ public class EventUtils {
         bus().removeStickyEvent(event);
     }
 
-    private static EventBus bus() {
-        return EventBus.getDefault();
+    private static EventBus createBus() {
+        EventBus bus = EventBus.builder()
+                .throwSubscriberException(BuildConfig.DEBUG)
+                .sendNoSubscriberEvent(false)
+                .addIndex(new EventBusIndex())
+                .installDefaultEventBus();
+
+        instance = new EventUtils();
+        bus.register(instance);
+
+        return bus;
+    }
+
+    private EventUtils() {}
+
+    @Subscribe
+    public void onSubscriberExceptionEvent(SubscriberExceptionEvent event) {
+        LOG.warn("onSubscriberExceptionEvent()", event.throwable);
     }
 
 }

app/src/main/java/dummydomain/yetanothercallblocker/MainActivity.java

@@ -15,7 +15,6 @@ import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.app.AppCompatActivity;
 import androidx.recyclerview.widget.RecyclerView;
 
-import org.greenrobot.eventbus.EventBus;
 import org.greenrobot.eventbus.Subscribe;
 import org.greenrobot.eventbus.ThreadMode;
 
@@ -92,7 +91,7 @@ public class MainActivity extends AppCompatActivity {
     protected void onStart() {
         super.onStart();
 
-        EventBus.getDefault().register(this);
+        EventUtils.register(this);
 
         startCheckMainDbTask();
 
@@ -103,7 +102,7 @@ public class MainActivity extends AppCompatActivity {
 
     @Override
     protected void onStop() {
-        EventBus.getDefault().unregister(this);
+        EventUtils.unregister(this);
 
         super.onStop();
     }
@@ -144,7 +143,7 @@ public class MainActivity extends AppCompatActivity {
 
             @Override
             protected void onPostExecute(Boolean result) {
-                if (!result && EventBus.getDefault().getStickyEvent(MainDbDownloadingEvent.class) == null) {
+                if (!result && EventUtils.bus().getStickyEvent(MainDbDownloadingEvent.class) == null) {
                     showNoMainDbDialog();
                 }
             }