Finished updating the preferences after reordering

app/src/main/java/gr/thmmy/mthmmy/activities/bookmarks/BookmarksActivity.java

@@ -77,6 +77,12 @@ public class BookmarksActivity extends BaseActivity {
         return false;
     }
 
+
+    public void swapBookmarksAfterReorder(Bookmark first, Bookmark second)
+    {
+        this.swapBookmarks(first, second);
+    }
+
     private boolean onTopicInteractionListener(String interactionType, Bookmark bookmarkedTopic) {
         switch (interactionType) {
             case BookmarksFragment.INTERACTION_CLICK_TOPIC_BOOKMARK:

app/src/main/java/gr/thmmy/mthmmy/activities/bookmarks/BookmarksFragment.java

@@ -1,6 +1,7 @@
 package gr.thmmy.mthmmy.activities.bookmarks;
 
 
+import android.app.Activity;
 import android.graphics.drawable.Drawable;
 import android.os.Build;
 import android.os.Bundle;
@@ -125,26 +126,39 @@ public class BookmarksFragment extends Fragment {
             public void onItemDragEnded(int fromPosition, int toPosition)
             {
 
-                //TODO: This only works locally. If the user exit the bookmarks
+                //If the drag and drop is not the same item.
-                // or closes the app, the order of the bookmarks will be lost.
-                // make sure after the following swapping, to apply the changes
-                // in the actual data model of the bookmarks.
-                // AFTER SWAPPING UPDATE THE ORDER OF THOSE TWO IN THE PREFERENCES.
-
                 if (fromPosition != toPosition)
                 {
+
+                    //Get the from bookmark.
                     Bookmark from = bookmarks.get(fromPosition);
 
+                    //Swap the from and to bookmarks.
                     bookmarks.set(fromPosition, bookmarks.get(toPosition));
                     bookmarks.set(toPosition, from);
+
+                    //Get the fragments activity.
+                    Activity unknownActivity = getActivity();
+
+                    //Update the order of the bookmarks in the preferences.
+                    if (unknownActivity instanceof BookmarksActivity)
+                    {
+                        //Cast to BookmarksActivity.
+                        BookmarksActivity activity = (BookmarksActivity)unknownActivity;
+
+                        //Call the swapBookmarksAfterReorder to apply the swapping changes to the preferences.
+                        activity.swapBookmarksAfterReorder( bookmarks.get(fromPosition), bookmarks.get(toPosition) );
+                    }
                 }
             }
         });
 
+        //====================================This is the code for the Drag and Drop Functionality====================================//
         mDragListView.setLayoutManager(new LinearLayoutManager(getActivity()));
         BookmarksAdapter adapter = new BookmarksAdapter(this, bookmarks, notificationsEnabledButtonImage, notificationsDisabledButtonImage);
         mDragListView.setAdapter(adapter, false);
         mDragListView.setCanDragHorizontally(false);
+        //====================================This is the code for the Drag and Drop Functionality====================================//
 
         //Hide Nothing Bookmarked.
         if(this.bookmarks != null && !this.bookmarks.isEmpty())
@@ -157,6 +171,7 @@ public class BookmarksFragment extends Fragment {
             showNothingBookmarked();
         }
 
+
         return rootView;
     }
 

app/src/main/java/gr/thmmy/mthmmy/base/BaseActivity.java

@@ -48,6 +48,7 @@ import net.gotev.uploadservice.UploadService;
 import java.io.File;
 import java.util.ArrayList;
 
+import gr.thmmy.mthmmy.BuildConfig;
 import gr.thmmy.mthmmy.R;
 import gr.thmmy.mthmmy.activities.AboutActivity;
 import gr.thmmy.mthmmy.activities.LoginActivity;
@@ -689,6 +690,87 @@ public abstract class BaseActivity extends AppCompatActivity {
             Timber.w("No bookmark match exists!");
         return false;
     }
+
+
+    //TODO: Abstract reusable code: find the index of the first and second bookmark.
+    protected void swapBookmarks(Bookmark first, Bookmark second)
+    {
+
+        //No need to check is second is a topics bookmark.
+        //because there is no way to drag and drop between topic and board.
+        if ( first.matchExists(topicsBookmarked) )
+        {
+            //Find the index of the first and second bookmark.
+            int firstIndex = -1, secondIndex = -1;
+            for (int i = 0; i < topicsBookmarked.size(); i++)
+            {
+
+                //Find the first index.
+                if (first.getId().equals(topicsBookmarked.get(i).getId()))
+                    firstIndex = i;
+
+                //Find the second index.
+                else if (second.getId().equals(topicsBookmarked.get(i).getId()))
+                    secondIndex = i;
+
+                //If both indexes found, stop.
+                if (firstIndex != -1 && secondIndex != -1)
+                    break;
+            }
+
+            //Assert, both indexes should have been found.
+            if (BuildConfig.DEBUG && !(firstIndex != -1 && secondIndex != -1)) {
+                throw new AssertionError("firstIndex and secondIndex must exist!");
+            }
+
+            //Temp store the first bookmark.
+            Bookmark firstBookmark = topicsBookmarked.get(firstIndex);
+
+            //Swap the bookmarks.
+            topicsBookmarked.set(firstIndex, topicsBookmarked.get(secondIndex));
+            topicsBookmarked.set(secondIndex, firstBookmark);
+
+            //Update the bookmarks.
+            updateTopicBookmarks();
+        }
+
+        //Swap on Board Bookmarks.
+        else if ( first.matchExists(boardsBookmarked) )
+        {
+            //Find the index of the first and second bookmark.
+            int firstIndex = -1, secondIndex = -1;
+            for (int i = 0; i < boardsBookmarked.size(); i++)
+            {
+
+                //Find the first index.
+                if (first.getId().equals(boardsBookmarked.get(i).getId()))
+                    firstIndex = i;
+
+
+                //Find the second index.
+                else if (second.getId().equals(boardsBookmarked.get(i).getId()))
+                    secondIndex = i;
+
+                //If both indexes found, stop.
+                if (firstIndex != -1 && secondIndex != -1)
+                    break;
+            }
+
+            if (BuildConfig.DEBUG && !(firstIndex != -1 && secondIndex != -1)) {
+                throw new AssertionError("firstIndex and secondIndex must exist!");
+            }
+
+            //Temp store the first bookmark.
+            Bookmark firstBookmark = boardsBookmarked.get(firstIndex);
+
+            //Swap the bookmarks.
+            boardsBookmarked.set(firstIndex, boardsBookmarked.get(secondIndex));
+            boardsBookmarked.set(secondIndex, firstBookmark);
+
+            //Update the bookmarks.
+            updateBoardBookmarks();
+        }
+    }
 //-------------------------------------------BOOKMARKS END------------------------------------------
 
     //-------PERMS---------