diff --git a/android/android-base/src/main/java/org/isoron/androidbase/activities/BaseSelectionMenu.java b/android/android-base/src/main/java/org/isoron/androidbase/activities/BaseSelectionMenu.kt
similarity index 65%
rename from android/android-base/src/main/java/org/isoron/androidbase/activities/BaseSelectionMenu.java
rename to android/android-base/src/main/java/org/isoron/androidbase/activities/BaseSelectionMenu.kt
index a1b486555..5d4b9af11 100644
--- a/android/android-base/src/main/java/org/isoron/androidbase/activities/BaseSelectionMenu.java
+++ b/android/android-base/src/main/java/org/isoron/androidbase/activities/BaseSelectionMenu.kt
@@ -16,50 +16,43 @@
  * You should have received a copy of the GNU General Public License along
  * with this program. If not, see <http://www.gnu.org/licenses/>.
  */
+package org.isoron.androidbase.activities
 
-package org.isoron.androidbase.activities;
-
-import androidx.annotation.NonNull;
-import androidx.annotation.Nullable;
-import androidx.appcompat.view.ActionMode;
-import android.view.*;
+import android.view.*
+import androidx.appcompat.view.ActionMode
 
 /**
  * Base class for all the selection menus in the application.
- * <p>
+ *
  * A selection menu is a menu that appears when the screen starts a selection
  * operation. It contains actions that modify the selected items, such as delete
  * or archive. Since it replaces the toolbar, it also has a title.
- * <p>
+ *
  * This class hides many implementation details of creating such menus in
- * Android. The interface is supposed to look very similar to {@link BaseMenu},
+ * Android. The interface is supposed to look very similar to [BaseMenu],
  * with a few additional methods, such as finishing the selection operation.
- * Internally, it uses an {@link ActionMode}.
+ * Internally, it uses an [ActionMode].
  */
-public abstract class BaseSelectionMenu
-{
-    @Nullable
-    private ActionMode actionMode;
+abstract class BaseSelectionMenu {
+    private var actionMode: ActionMode? = null
 
     /**
      * Finishes the selection operation.
      */
-    public void finish()
-    {
-        if (actionMode != null) actionMode.finish();
+    fun finish() {
+        actionMode?.finish()
     }
 
     /**
      * Declare that the menu has changed, and should be recreated.
      */
-    public void invalidate()
-    {
-        if (actionMode != null) actionMode.invalidate();
+    fun invalidate() {
+        actionMode?.invalidate()
     }
 
     /**
      * Called when the menu is first displayed.
-     * <p>
+     *
      * This method should not be overridden. The application should override
      * the methods onCreate(Menu) and getMenuResourceId instead.
      *
@@ -67,22 +60,16 @@ public abstract class BaseSelectionMenu
      * @param mode     the action mode associated with this menu.
      * @param menu     the menu that is being created.
      */
-    public void onCreate(@NonNull MenuInflater inflater,
-                         @NonNull ActionMode mode,
-                         @NonNull Menu menu)
-    {
-        this.actionMode = mode;
-        inflater.inflate(getResourceId(), menu);
-        onCreate(menu);
+    fun onCreate(inflater: MenuInflater, mode: ActionMode, menu: Menu) {
+        actionMode = mode
+        inflater.inflate(getResourceId(), menu)
+        onCreate(menu)
     }
 
     /**
      * Called when the selection operation is about to finish.
      */
-    public void onFinish()
-    {
-
-    }
+    open fun onFinish() {}
 
     /**
      * Called whenever an item on the menu is selected.
@@ -90,11 +77,7 @@ public abstract class BaseSelectionMenu
      * @param item the item that was selected.
      * @return true if the event was consumed, or false otherwise
      */
-    public boolean onItemClicked(@NonNull MenuItem item)
-    {
-        return false;
-    }
-
+    open fun onItemClicked(item: MenuItem): Boolean = false
 
     /**
      * Called whenever the menu is invalidated.
@@ -102,29 +85,23 @@ public abstract class BaseSelectionMenu
      * @param menu the menu to be refreshed
      * @return true if the menu has changes, false otherwise
      */
-    public boolean onPrepare(@NonNull Menu menu)
-    {
-        return false;
-    }
+    open fun onPrepare(menu: Menu): Boolean = false
 
     /**
      * Sets the title of the selection menu.
      *
      * @param title the new title.
      */
-    public void setTitle(String title)
-    {
-        if (actionMode != null) actionMode.setTitle(title);
+    fun setTitle(title: String?) {
+        actionMode?.title = title
     }
 
-    protected abstract int getResourceId();
+    protected abstract fun getResourceId(): Int
 
     /**
      * Called when the menu is first created.
      *
      * @param menu the menu being created
      */
-    protected void onCreate(@NonNull Menu menu)
-    {
-    }
-}
+    protected fun onCreate(menu: Menu) {}
+}
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