NativeScript/apps/app/ui-tests-app/list-picker/issue_2895.ts

import { Page } from 'tns-core-modules/ui/page';
import { Observable } from "tns-core-modules/data/observable";
import { EventData } from "tns-core-modules/ui/core/view";

export function navigatingTo(args: EventData) {
    let page = <Page>args.object;
    page.bindingContext = new ListPickerView();
}

export class ListPickerView extends Observable {

    private _showListPicker: string = "collapsed";
    private _isVisisble: boolean;

    constructor() {
        super();
        this._isVisisble = false;
    }

    get options(): Array<String> {
        return ["options1", "options2", "options3", "options1", "options2", "options3"];
    }

    get showListPicker(): string {
        return this._showListPicker;
    }

    set showListPicker(value: string) {
        if (this._showListPicker !== value) {
            this._showListPicker = value;
            this.notifyPropertyChange("showListPicker", value)
        }
    }

    public onTap() {
        this._isVisisble ? this.showListPicker = "collapsed" : this.showListPicker = "visible";
        this._isVisisble = !this._isVisisble;
    }
}