Ion-item sliding not working

I am adding sliding to my list,on silding right I have a call button,
but the sliding does not work and no button is visible,because of no sliding…Please help me where I am wrong…
I want to add call button on my contact list,on right slide of the items…

This is my html code…

 <ion-item-group *ngFor="let group of groupedContacts">
    <ion-item-divider color="light">{{group.letter}}</ion-item-divider>   

        <ion-item-sliding  *ngFor="let contact of group.contacts" class="contactlist" >
           <ion-item-options side="right">
    <button ion-button color="secondary" *ngIf="contact.phoneNumbers"
      <ion-icon name="call"> Call</ion-icon>

my typescript code:-

import { Component } from '@angular/core';
import { NavController,Platform ,PopoverController,ViewController} from 'ionic-angular';
import { Contacts } from '@ionic-native/contacts';
import {SMS} from '@ionic-native/sms';
  selector: 'page-about',
  templateUrl: 'about.html'
export class AboutPage {
 contacts = []
 groupedContacts = []

  constructor(public navCtrl: NavController,public co:Contacts,public viewCtrl:ViewController,public popoverCtrl:PopoverController,
  public callNumber:CallNumber,public sms:SMS) {


    co.find(["displayName", "phoneNumbers"], {multiple: true, hasPhoneNumber: true}).then((contacts) => {

    for (var i=0 ; i < contacts.length; i++){
     if(contacts[i].displayName !== null){
       var obj = {};
       obj["name"] = contacts[i].displayName;
       obj["number"] = contacts[i].phoneNumbers[0].value;




 callContact(number: string) {
    this.callNumber.callNumber(number, true)
      .then(() => console.log('Dialer Launched!'))
      .catch(() => console.log('Error launching dialer'));


  let sortedContacts = contacts.sort(function(a, b){
    if( < return -1;
    if( > return 1;
    return 0;

  let currentLetter = false;
  let currentContacts = [];

  sortedContacts.forEach((value, index) => {
    if( != currentLetter){
      currentLetter =;

      let newGroup ={
        letter: currentLetter,

      currentContacts = newGroup.contacts;


Did you figure out the solution? I am in a same trouble.
It works only when *ngIf part is removed