fix #164

Author: PeterStaev

drop-down-common.ts

@@ -15,6 +15,7 @@ limitations under the License.
 ***************************************************************************** */
 import { ObservableArray } from "data/observable-array";
 import { CoercibleProperty, Property, View } from "ui/core/view";
+import { addWeakEventListener, removeWeakEventListener } from "ui/core/weak-event-listener";
 import { ItemsSource } from "ui/list-picker";
 import * as types from "utils/types";
 import { DropDown as DropDownDefinition, ValueItem, ValueList as ValueListDefinition } from ".";
@@ -35,6 +36,7 @@ export abstract class DropDownBase extends View implements DropDownDefinition {
 
     public abstract open();
     public abstract close();
+    public abstract refresh();
 
     public _getItemAsString(index: number) {
         const items = this.items;
@@ -130,6 +132,14 @@ export const itemsProperty = new Property<DropDownBase, any[] | ItemsSource>({
 
         target.isItemsSourceIn = typeof getItem === "function";
         target.isValueListIn = typeof getDisplay === "function";
+
+        if (oldValue instanceof ObservableArray) {
+            removeWeakEventListener(oldValue, ObservableArray.changeEvent, target.refresh, target);
+        }
+
+        if (newValue instanceof ObservableArray) {
+            addWeakEventListener(newValue, ObservableArray.changeEvent, target.refresh, target);
+        }
     }
 });
 itemsProperty.register(DropDownBase);

drop-down.android.ts

@@ -117,12 +117,18 @@ export class DropDown extends DropDownBase {
         this.nativeView.onDetachedFromWindowX();
     }
 
+    public refresh() {
+        this._updateSelectedIndexOnItemsPropertyChanged(this.items);
+        (this.android.getAdapter() as DropDownAdapter).notifyDataSetChanged();
+
+        // Coerce selected index after we have set items to native view.
+        selectedIndexProperty.coerce(this);
+    }
+
     public [selectedIndexProperty.getDefault](): number {
         return null;
     }
     public [selectedIndexProperty.setNative](value: number) {
-        this._clearCache(RealizedViewType.DropDownView);
-
         const actualIndex = (types.isNullOrUndefined(value) ? 0 : value + 1);
         this.nativeView.setSelection(actualIndex);
     }
@@ -195,6 +201,16 @@ export class DropDown extends DropDownBase {
         return this._realizedItems[realizedViewType].get(convertView);
     }
 
+    public _clearCache(realizedViewType: RealizedViewType) {
+        const realizedItems = this._realizedItems[realizedViewType];
+        realizedItems.forEach((view) => {
+            if (view.parent) {
+                view.parent._removeView(view);
+            }
+        });
+        realizedItems.clear();
+    }
+
     private _propagateStylePropertyToRealizedViews(property: string, value: any, isIncludeHintIn = true) {
         const realizedItems = this._realizedItems;
         for (const item of realizedItems) {
@@ -224,16 +240,6 @@ export class DropDown extends DropDownBase {
             this.selectedIndex = null;
         }
     }
-
-    private _clearCache(realizedViewType: RealizedViewType) {
-        const realizedItems = this._realizedItems[realizedViewType];
-        realizedItems.forEach((view) => {
-            if (view.parent) {
-                view.parent._removeView(view);
-            }
-        });
-        realizedItems.clear();
-    }
 }
 
 /* A snapshot-friendly, lazy-loaded class for TNSSpinner BEGIN */
@@ -285,6 +291,8 @@ function initializeTNSSpinner() {
                     eventName: DropDownBase.closedEvent,
                     object: owner
                 });
+                
+                owner._clearCache(RealizedViewType.DropDownView);
             }
         }
 

drop-down.ios.ts

@@ -136,6 +136,13 @@ export class DropDown extends DropDownBase {
         this.ios.resignFirstResponder();
     }
 
+    public refresh() {
+        this._listPicker.reloadAllComponents();
+
+        // Coerce selected index after we have set items to native view.
+        selectedIndexProperty.coerce(this);
+    }
+
     public [selectedIndexProperty.getDefault](): number {
         return null;
     }
@@ -151,10 +158,7 @@ export class DropDown extends DropDownBase {
         return null;
     }
     public [itemsProperty.setNative](value: any[] | ItemsSource) {
-        this._listPicker.reloadAllComponents();
-
-        // Coerce selected index after we have set items to native view.
-        selectedIndexProperty.coerce(this);
+        this.refresh();
     }
 
     public [hintProperty.getDefault](): string {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "nativescript-drop-down",
-  "version": "3.2.1",
+  "version": "3.2.2",
   "description": "A NativeScript DropDown widget.",
   "main": "drop-down",
   "typings": "drop-down.d.ts",