fix no showing activities on resume

Signed-off-by: tobiasKaminsky <tobias@kaminsky.me>

src/main/java/com/owncloud/android/ui/activities/ActivitiesActivity.java

@@ -230,6 +230,8 @@ public class ActivitiesActivity extends FileActivity implements ActivityListInte
     protected void onResume() {
         super.onResume();
 
+        mActionListener.onResume();
+
         setDrawerMenuItemChecked(R.id.nav_activity);
 
         setupContent();
@@ -325,6 +327,6 @@ public class ActivitiesActivity extends FileActivity implements ActivityListInte
     protected void onStop() {
         super.onStop();
 
-        mActionListener.stopLoadingActivity();
+        mActionListener.onStop();
     }
 }

src/main/java/com/owncloud/android/ui/activities/ActivitiesContract.java

@@ -1,4 +1,4 @@
-/**
+/*
  *   Nextcloud Android client application
  *
  *   Copyright (C) 2018 Edvard Holst
@@ -42,6 +42,8 @@ public interface ActivitiesContract {
 
         void openActivity(String fileUrl, BaseActivity baseActivity);
 
-        void stopLoadingActivity();
+        void onStop();
+
+        void onResume();
     }
 }

src/main/java/com/owncloud/android/ui/activities/ActivitiesPresenter.java

@@ -1,4 +1,4 @@
-/**
+/*
  * Nextcloud Android client application
  *
  * Copyright (C) 2018 Edvard Holst
@@ -93,7 +93,12 @@ public class ActivitiesPresenter implements ActivitiesContract.ActionListener {
     }
 
     @Override
-    public void stopLoadingActivity() {
+    public void onStop() {
         activityStopped = true;
     }
+
+    @Override
+    public void onResume() {
+        activityStopped = false;
+    }
 }