Show/Hide action button depending on scroll direction

app/src/main/java/com/beemdevelopment/aegis/ui/MainActivity.java

@@ -1,6 +1,8 @@
 package com.beemdevelopment.aegis.ui;
 
 import android.Manifest;
+import android.animation.Animator;
+import android.animation.AnimatorListenerAdapter;
 import android.content.ClipData;
 import android.content.ClipboardManager;
 import android.content.Context;
@@ -12,6 +14,9 @@ import android.view.Menu;
 import android.view.MenuItem;
 import android.view.MotionEvent;
 import android.view.SubMenu;
+import android.view.View;
+import android.view.animation.AccelerateInterpolator;
+import android.view.animation.DecelerateInterpolator;
 import android.widget.LinearLayout;
 import android.widget.Toast;
 
@@ -31,6 +36,9 @@ import com.beemdevelopment.aegis.db.DatabaseManagerException;
 import com.beemdevelopment.aegis.db.DatabaseEntry;
 import com.beemdevelopment.aegis.db.DatabaseManager;
 
+import androidx.coordinatorlayout.widget.CoordinatorLayout;
+import androidx.interpolator.view.animation.FastOutSlowInInterpolator;
+
 public class MainActivity extends AegisActivity implements EntryListView.Listener {
     // activity request codes
     private static final int CODE_SCAN = 0;
@@ -499,4 +507,39 @@ public class MainActivity extends AegisActivity implements EntryListView.Listene
     public void onEntryChange(DatabaseEntry entry) {
         saveDatabase();
     }
+
+    private boolean isAnimating;
+
+    @Override
+    public void onScroll(int dx, int dy) {
+        if (dy > 0 && _fabMenu.getVisibility() == View.VISIBLE && !isAnimating) {
+            isAnimating = true;
+            CoordinatorLayout.LayoutParams lp = (CoordinatorLayout.LayoutParams) _fabMenu.getLayoutParams();
+            int fabBottomMargin = lp.bottomMargin;
+            _fabMenu.animate()
+                    .translationY(_fabMenu.getHeight() + fabBottomMargin)
+                    .setInterpolator(new AccelerateInterpolator(2))
+                    .setListener(new AnimatorListenerAdapter() {
+                        @Override
+                        public void onAnimationEnd(Animator animation) {
+                            isAnimating = false;
+                            _fabMenu.setVisibility(View.INVISIBLE);
+                            super.onAnimationEnd(animation);
+                        }
+                    }).start();
+        }
+         else if (dy < 0 && _fabMenu.getVisibility() != View.VISIBLE && !isAnimating) {
+            _fabMenu.setVisibility(View.VISIBLE);
+            _fabMenu.animate()
+                    .translationY(0)
+                    .setInterpolator(new DecelerateInterpolator(2))
+                    .setListener(new AnimatorListenerAdapter() {
+                        @Override
+                        public void onAnimationEnd(Animator animation) {
+                            isAnimating = false;
+                            super.onAnimationEnd(animation);
+                        }
+                    }).start();
+        }
+    }
 }

app/src/main/java/com/beemdevelopment/aegis/ui/views/EntryListView.java

@@ -3,6 +3,8 @@ package com.beemdevelopment.aegis.ui.views;
 import android.content.Context;
 import android.graphics.PorterDuff;
 import android.os.Bundle;
+
+import androidx.annotation.NonNull;
 import androidx.fragment.app.Fragment;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
@@ -33,6 +35,8 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
 
     private UiRefresher _refresher;
 
+    private RecyclerView.OnScrollChangeListener _onScrollListener;
+
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -50,6 +54,14 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
 
         // set up the recycler view
         _rvKeyProfiles = view.findViewById(R.id.rvKeyProfiles);
+        _rvKeyProfiles.addOnScrollListener(new RecyclerView.OnScrollListener() {
+            @Override
+            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
+                super.onScrolled(recyclerView, dx, dy);
+                _listener.onScroll(dx, dy);
+            }
+        });
+
         LinearLayoutManager mLayoutManager = new LinearLayoutManager(view.getContext());
         _rvKeyProfiles.setLayoutManager(mLayoutManager);
         _touchCallback = new SimpleItemTouchHelperCallback(_adapter);
@@ -199,5 +211,7 @@ public class EntryListView extends Fragment implements EntryAdapter.Listener {
         void onEntryMove(DatabaseEntry entry1, DatabaseEntry entry2);
         void onEntryDrop(DatabaseEntry entry);
         void onEntryChange(DatabaseEntry entry);
+        void onScroll(int dx, int dy);
+
     }
 }