Ionic keyboard doesn't show

Ionic Framework ionic-v3
1

hi , I am using ionic 3 and I am trying to show keyboard automatically when navigating to a specific page

.ts:

 constructor(
   public navCtrl: NavController, 
   public navParams: NavParams,
   private keyboard: Keyboard) {}

 ionViewDidLoad() {
   console.log('ionViewDidLoad PostDetailsPage');
   let post = this.navParams.get('post')

   this.keyboard.show()
 }

Does it require there to be an Input ??
Also I want the Input text to be floating above the keyboard , not sure how to do it ! Any suggestion would help , thanx.