diff --git a/bubblepicker/src/main/java/com/kienht/bubblepicker/rendering/BubblePicker.kt b/bubblepicker/src/main/java/com/kienht/bubblepicker/rendering/BubblePicker.kt
index f526f09..adb66d7 100755
--- a/bubblepicker/src/main/java/com/kienht/bubblepicker/rendering/BubblePicker.kt
+++ b/bubblepicker/src/main/java/com/kienht/bubblepicker/rendering/BubblePicker.kt
@@ -24,7 +24,7 @@ class BubblePicker : GLSurfaceView {
             renderer.backgroundColor = Color(value)
         }
 
-    var datas: ArrayList<PickerItem>? = null
+    var datas: List<PickerItem>? = null
         set(value) {
             field = value
             renderer.items = value ?: ArrayList()
diff --git a/bubblepicker/src/main/java/com/kienht/bubblepicker/rendering/PickerRenderer.kt b/bubblepicker/src/main/java/com/kienht/bubblepicker/rendering/PickerRenderer.kt
index 83cd8fc..98b805c 100755
--- a/bubblepicker/src/main/java/com/kienht/bubblepicker/rendering/PickerRenderer.kt
+++ b/bubblepicker/src/main/java/com/kienht/bubblepicker/rendering/PickerRenderer.kt
@@ -42,7 +42,7 @@ class PickerRenderer(val glView: View) : GLSurfaceView.Renderer {
             Engine.radius = value
         }
     var listener: BubblePickerListener? = null
-    var items: ArrayList<PickerItem> = ArrayList()
+    var items: List<PickerItem> = ArrayList()
     val selectedItems: List<PickerItem?>
         get() = Engine.selectedBodies.map { circles.firstOrNull { circle -> circle.circleBody == it }?.pickerItem }
     var centerImmediately = false