Merge pull request #629 from NativeScript/scrollToIndex-

scrollToIndex added to ListView

apps/tests/ui/list-view/list-view-tests.ts

@@ -459,6 +459,26 @@ export function test_loadMoreItems_not_raised_when_showing_many_items() {
     helper.buildUIAndRunTest(listView, testAction);
 }
 
+export function test_loadMoreItems_is_raised_when_scroll_to_last_item() {
+    var listView = new listViewModule.ListView();
+    listView.on(listViewModule.ListView.itemLoadingEvent, loadViewWithItemNumber);
+
+    function testAction(views: Array<viewModule.View>) {
+        var loadMoreItemsCount = 0;
+        listView.items = MANY_ITEMS;
+        listView.on(listViewModule.ListView.loadMoreItemsEvent, function (data: observable.EventData) {
+            loadMoreItemsCount++;
+        });
+
+        listView.scrollToIndex(MANY_ITEMS.length - 1);
+
+        TKUnit.wait(ASYNC);
+        TKUnit.assertEqual(loadMoreItemsCount, 1, "loadMoreItemsCount");
+    };
+
+    helper.buildUIAndRunTest(listView, testAction);
+}
+
 export function test_usingAppLevelConvertersInListViewItems() {
     var listView = new listViewModule.ListView();
 

ui/list-view/list-view-common.ts

@@ -101,6 +101,10 @@ export class ListView extends view.View implements definition.ListView {
         //
     }
 
+    public scrollToIndex(index: number) {
+        //
+    }
+
     public _getItemTemplateContent(index: number): view.View {
         var v;
 

ui/list-view/list-view.android.ts

@@ -102,6 +102,12 @@ export class ListView extends common.ListView {
         (<ListViewAdapter>this.android.getAdapter()).notifyDataSetChanged();
     }
 
+    public scrollToIndex(index: number) {
+        if (this._android) {
+            this._android.setSelection(index);
+        }
+    }
+
     public _onDetached(force?: boolean) {
         super._onDetached(force);
 

ui/list-view/list-view.d.ts

@@ -85,6 +85,14 @@ declare module "ui/list-view" {
          */
         refresh();
 
+        /**
+         * Scrolls the specified item with index into view. 
+         * [iOS](https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UITableView_Class/#//apple_ref/occ/instm/UITableView/scrollToRowAtIndexPath:atScrollPosition:animated:)
+         * [Android](http://developer.android.com/reference/android/widget/ListView.html#setSelection(int))
+         * @param index - Item index. 
+         */
+        scrollToIndex(index: number);
+
         /**
          * A basic method signature to hook an event listener (shortcut alias to the addEventListener method).
          * @param eventNames - String corresponding to events (e.g. "propertyChange"). Optionally could be used more events separated by `,` (e.g. "propertyChange", "change"). 

ui/list-view/list-view.ios.ts

@@ -173,6 +173,13 @@ export class ListView extends common.ListView {
         return this._ios;
     }
 
+    public scrollToIndex(index: number) {
+        if (this._ios) {
+            this._ios.scrollToRowAtIndexPathAtScrollPositionAnimated(NSIndexPath.indexPathForItemInSection(index, 0),
+                UITableViewScrollPosition.UITableViewScrollPositionTop, true);
+        }
+    }
+
     public refresh() {
         if (this.isLoaded) {
             this._ios.reloadData();