fix: add additional checks to expandable views of BoardAdapter

app/src/main/java/gr/thmmy/mthmmy/activities/board/BoardAdapter.java

@@ -3,7 +3,6 @@ package gr.thmmy.mthmmy.activities.board;
 import android.content.Context;
 import android.content.Intent;
 import android.graphics.Typeface;
-import android.os.Build;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -104,7 +103,7 @@ class BoardAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
                 intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                 context.startActivity(intent);
             });
-            if (boardExpandableVisibility.get(subBoardViewHolder.getAdapterPosition())) {
+            if (boardExpandableVisibility.get(subBoardViewHolder.getBindingAdapterPosition())) {
                 subBoardViewHolder.boardExpandable.setVisibility(View.VISIBLE);
                 subBoardViewHolder.showHideExpandable.setImageResource(R.drawable.ic_arrow_drop_up_accent_24dp);
             }
@@ -113,7 +112,9 @@ class BoardAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
                 subBoardViewHolder.showHideExpandable.setImageResource(R.drawable.ic_arrow_drop_down_accent_24dp);
             }
             subBoardViewHolder.showHideExpandable.setOnClickListener(view -> {
-                final boolean visible = boardExpandableVisibility.get(subBoardViewHolder.getAdapterPosition());
+                final int pos = subBoardViewHolder.getBindingAdapterPosition();
+                if (pos >=0 && pos < boardExpandableVisibility.size()){
+                    final boolean visible = boardExpandableVisibility.get(subBoardViewHolder.getBindingAdapterPosition());
                     if (visible) {
                         subBoardViewHolder.boardExpandable.setVisibility(View.GONE);
                         subBoardViewHolder.showHideExpandable.setImageResource(R.drawable.ic_arrow_drop_down_accent_24dp);
@@ -122,7 +123,8 @@ class BoardAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
                         subBoardViewHolder.boardExpandable.setVisibility(View.VISIBLE);
                         subBoardViewHolder.showHideExpandable.setImageResource(R.drawable.ic_arrow_drop_up_accent_24dp);
                     }
-                boardExpandableVisibility.set(subBoardViewHolder.getAdapterPosition(), !visible);
+                    boardExpandableVisibility.set(subBoardViewHolder.getBindingAdapterPosition(), !visible);
+                }
             });
             subBoardViewHolder.boardTitle.setText(subBoard.getTitle());
             String mods = subBoard.getMods();
@@ -174,7 +176,7 @@ class BoardAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
                 intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
                 context.startActivity(intent);
             });
-            if (topicExpandableVisibility.get(topicViewHolder.getAdapterPosition() - parsedSubBoards
+            if (topicExpandableVisibility.get(topicViewHolder.getBindingAdapterPosition() - parsedSubBoards
                     .size())) {
                 topicViewHolder.topicExpandable.setVisibility(View.VISIBLE);
                 topicViewHolder.showHideExpandable.setImageResource(R.drawable.ic_arrow_drop_up_accent_24dp);
@@ -184,8 +186,10 @@ class BoardAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
                 topicViewHolder.showHideExpandable.setImageResource(R.drawable.ic_arrow_drop_down_accent_24dp);
             }
             topicViewHolder.showHideExpandable.setOnClickListener(view -> {
+                final int pos = topicViewHolder.getBindingAdapterPosition() - parsedSubBoards.size();
+                if (pos >=0 && pos < topicExpandableVisibility.size()) {
                     final boolean visible = topicExpandableVisibility.get(topicViewHolder.
-                        getAdapterPosition() - parsedSubBoards.size());
+                            getBindingAdapterPosition() - parsedSubBoards.size());
                     if (visible) {
                         topicViewHolder.topicExpandable.setVisibility(View.GONE);
                         topicViewHolder.showHideExpandable.setImageResource(R.drawable.ic_arrow_drop_down_accent_24dp);
@@ -194,17 +198,17 @@ class BoardAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
                         topicViewHolder.topicExpandable.setVisibility(View.VISIBLE);
                         topicViewHolder.showHideExpandable.setImageResource(R.drawable.ic_arrow_drop_up_accent_24dp);
                     }
-                topicExpandableVisibility.set(topicViewHolder.getAdapterPosition() -
+                    topicExpandableVisibility.set(topicViewHolder.getBindingAdapterPosition() -
                             parsedSubBoards.size(), !visible);
+                }
             });
             topicViewHolder.topicSubject.setTypeface(Typeface.createFromAsset(context.getAssets()
                     , "fonts/fontawesome-webfont.ttf"));
             topicViewHolder.topicUnreadDot.setTypeface(Typeface.createFromAsset(context.getAssets(), "fonts/fontawesome-webfont.ttf"));
             if (topic.isUnread())
                 topicViewHolder.topicUnreadDot.setVisibility(View.VISIBLE);
-            else {
+            else
                 topicViewHolder.topicUnreadDot.setVisibility(View.GONE);
-            }
             String lockedSticky = topic.getSubject();
             if (topic.isLocked())
                 lockedSticky += " " + context.getResources().getString(R.string.fa_lock);