Changing tabs dynamically in Ionic 2

Question

I am creating an Ionic application where I am using tabs. I want to be able to navigate from one tab to the other using the typescript component class attached to the tab template. For example, Tab 2 should be activated upon triggering an event in tab 1.

My tab loads well in the tabs and all is well as long as I manually click on the tab to move around, but trying to switch context in the code behind as been very tricky.

At load time I am able to make any one of the tabs active by simply setting the [selectedIndex] attribute of the ion-tabs to the value of an attribute in my tabs component class.

Tabs Parent Template - tab.html

<ion-tabs #tabParent [selectedIndex]="tabToShow">
  <ion-tab tabTitle="Tab 1" [root]="tab2" [rootParams]="{parent : tabParent}"></ion-tab>
  <ion-tab tabTitle="Tab 2" [root]="tab2" [rootParams]="{parent : tabParent}></ion-tab>
  <ion-tab tabTitle="Tab 3" [root]="tab3" [rootParams]="{parent : tabParent}></ion-tab>
</ion-tabs>

Component - tab.ts

import {Page} from 'ionic-angular';
import {Tab1} from '../tab1/tab1.ts';
import {Tab2} from '../tab2/tab2.ts';
import {Tab3} from '../tab3/tab3.ts';

@Page({
templateUrl : 'build/pages/tab/tab.html'
})

export class Tab{

tab1: any;
tab2: any;
tab3: any;

tabToShow : number = 1;

ngOnInit(){
 this.tab1 = Tab1;
 this.tab2 = Tab2;
 this.tab3 = Tab3;
 }

}

In the component for the first tab (Tab1), i am able to get a reference to the parent tabs by using [rootParams] = "{parent : tabParent}" and I am able access all available properties exposed by the tabs object. An event generated on the tab1.html template, causes the goToTab2() to be called. So, I was able to set SelectedIndex to 1 (which I expect to change the active tab to the second tab). But the tab is not changing.

tab1.ts

import {Page, NavParams} from 'ionic-angular';
import {Tab2} from '../tab/tab2/tab2.ts'

@Page({
 templateUrl : 'build/pages/tab/tab1/tab1.html'
})

export class Tab1{

parent : any;

constructor(nav : NavParams){
this.parent = nav.data;
}

goToTab2(event, value): void{
 this.parent.parent.selectedIndex = 1;
 console.log(this.parent.parent);
 }

}

I need help, what am I doing wrong?

Answer 1

I had the same problem and after hours of trying and debugging, it turned out to be so simple:

import {Page, NavController, Tabs} from 'ionic-angular';

@Page({
 templateUrl : 'build/pages/tab/tab1/tab1.html'
})

export class Tab1{
    constructor(private nav: NavController) {
    };
    selectTab(index: number) {
        var t: Tabs = this.nav.parent;
        t.select(index);
    }
}

Answer 2

this.nav.parent.select(tabIndex); 

tabIndex starts from 0