Show "no network" snackbar when tapping some settings

A couple of settings don't work properly when network is not available so this
commit adds a "guard", preventing those actions to continue and showing a
snackbar with a "no network" message, similar to what the PagesFragment has.

The settings affected are:
- Parent Page
  To avoid the user selecting an invalid page as parent (that is not yet
  published remotely), it's better to disable the access to this option while
  offline to avoid issues.
- Author
  The author list doesn't load properly while offline, showing a Dialog with
  a "Loading..." message.

Author: thomashorta

WordPress/src/main/java/org/wordpress/android/ui/posts/EditPostSettingsFragment.java

@@ -28,6 +28,8 @@
 import androidx.lifecycle.Observer;
 import androidx.lifecycle.ViewModelProvider;
 
+import com.google.android.material.snackbar.Snackbar;
+
 import org.apache.commons.text.StringEscapeUtils;
 import org.greenrobot.eventbus.Subscribe;
 import org.greenrobot.eventbus.ThreadMode;
@@ -68,11 +70,13 @@
 import org.wordpress.android.util.AppLog;
 import org.wordpress.android.util.AppLog.T;
 import org.wordpress.android.util.DateTimeUtils;
+import org.wordpress.android.util.NetworkUtilsWrapper;
 import org.wordpress.android.util.StringUtils;
 import org.wordpress.android.util.analytics.AnalyticsTrackerWrapper;
 import org.wordpress.android.util.image.ImageManager;
 import org.wordpress.android.util.image.ImageManager.RequestListener;
 import org.wordpress.android.util.image.ImageType;
+import org.wordpress.android.widgets.WPSnackbar;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -149,6 +153,7 @@ public class EditPostSettingsFragment extends Fragment {
     @Inject UpdatePostStatusUseCase mUpdatePostStatusUseCase;
     @Inject MediaPickerLauncher mMediaPickerLauncher;
     @Inject UpdateFeaturedImageUseCase mUpdateFeaturedImageUseCase;
+    @Inject NetworkUtilsWrapper mNetworkUtilsWrapper;
 
     @Inject ViewModelProvider.Factory mViewModelFactory;
     private EditPostPublishSettingsViewModel mPublishedViewModel;
@@ -573,6 +578,11 @@ private void showPageParentActivity() {
             return;
         }
 
+        if (!mNetworkUtilsWrapper.isNetworkAvailable()) {
+            showNoNetworkSnackbar();
+            return;
+        }
+
         long remoteId = repository.getRemotePostId();
         ActivityLauncher.viewPageParentForResult(this, site, remoteId);
     }
@@ -687,6 +697,11 @@ private void showAuthorDialog() {
             return;
         }
 
+        if (!mNetworkUtilsWrapper.isNetworkAvailable()) {
+            showNoNetworkSnackbar();
+            return;
+        }
+
         FragmentManager fm = getActivity().getSupportFragmentManager();
 
         PostSettingsListDialogFragment fragment = PostSettingsListDialogFragment.newAuthorListInstance(getAuthorId());
@@ -1308,8 +1323,18 @@ private void hideSpecificViews(Boolean isPage) {
         }
     }
 
+    private void showNoNetworkSnackbar() {
+        String message = getString(R.string.no_network_message);
+        WPSnackbar.make(
+                requireView().findViewById(R.id.settings_fragment_root),
+                message,
+                Snackbar.LENGTH_LONG
+        ).show();
+    }
+
     interface EditPostSettingsCallback {
         void onEditPostPublishedSettingsClick();
+
         void clearFeaturedImage();
     }
 }