Tabs is not displaying in HomePage

I am trying to use scrollable tabs for the news application but is not displaying at all. I wonder what went wrong. Here is my code.

home.html

ion-tabs
    #tabs
    tabsPlacement="top"
    color="primary">
    <ion-tab
      *ngFor="let item of api?.parentMenu"
      [tabTitle]="item.name"
      [root]="openPage(item.id)">
    </ion-tab>
  </ion-tabs>

home.ts

 openPage(cat_id:number = 0){

        if(this.navParams.get("cat_id")!=null && this.navParams.get("cat_id")!=undefined){
            this.category_id=this.navParams.get("cat_id");
        }
        this.getPosts();
    }

Please help.

Any Suggestions ? Is there any links so that I can move further ?