RadListView better scrollToIndex() behavior - nativescript

Question

RadListView.scrollToIndex() seems to display the selected item at the bottom of the current window always - regardless of whether the item is already visible or not.
Is there a function like RadListView.isVisible()?

Answer 1

I have just tested the given scenario with scrollToIndex() and was unable to reproduce such a behavior. Selected row has been always displayed in the top of the screen. You could review my sample code.
main-page.xml
<Page loaded="onPageLoaded" xmlns:lv="nativescript-telerik-ui-pro/listview" xmlns="http://www.nativescript.org/tns.xsd">
<lv:RadListView id="rdid" loaded="radlistviewlaoded" items="{{ dataItems }}" >
<lv:RadListView.listViewLayout>
<lv:ListViewLinearLayout scrollDirection="Vertical"/>
</lv:RadListView.listViewLayout>
<lv:RadListView.itemTemplate>
<StackLayout orientation="vertical">
<Label fontSize="20" text="{{ itemName }}"/>
<Label fontSize="14" text="{{ itemDescription }}"/>
</StackLayout>
</lv:RadListView.itemTemplate>
</lv:RadListView>
</Page>
main-page.ts
import { EventData } from "data/observable";
import { Page } from "ui/page";
import { HelloWorldModel } from "./main-view-model";
import { ObservableArray } from "data/observable-array";
import { RadListView } from "nativescript-telerik-ui-pro/listview";
import {setTimeout} from "timer"
// Event handler for Page "navigatingTo" event attached in main-page.xml
export function onPageLoaded(args: EventData) {
// Get the event sender
var page = <Page>args.object;
var listview:RadListView = <RadListView> page.getViewById("rdid");
console.log("listview visibility "+listview.visibility);
//listview.scrollToIndex(3);
var array = new ObservableArray();
for(var i=0;i<20;i++){
array.push({itemName:"Name "+i, itemDescription:"desc "+i});
}
setTimeout(function(){
listview.scrollToIndex(3)
}, 2000)
page.bindingContext = {dataItems:array};
}
export function radlistviewlaoded(args:EventData){
console.log("RadListView loaded");
}
About the second question you could use loaded event in case you want to know when the view has been loaded on the screen. In case you would like to know if the RadListview is visible you could use visibility property.