ionic back button does not change text dynamically - ionic-framework

Question

After setting back button text using config,
it does not reflect right away in nav bar.
Have to pop and push the page again.
playground:
https://stackblitz.com/edit/backbuttonbug.
you can see in contact page,
setting back button text does not reflect in self page and even in other nav stack
code:
previous page:
export class AboutPage {
constructor(public navCtrl: NavController) {}
contact() {
this.navCtrl.push(ContactPage);
}
}
Next page:
export class ContactPage {
constructor(public navCtrl: NavController,
public config: Config) {}
toChinese() {
this.config.set("backButtonText", '返回');
}
toEnglish() {
this.config.set("backButtonText", 'back');
}
}
<ion-header>
<ion-navbar>
<ion-title>
Contact
</ion-title>
</ion-navbar>
</ion-header>
<ion-content>
<button ion-button (tap)="toChinese()">toChinese</button>
<button ion-button (tap)="toEnglish()">toEnglish</button>
</ion-content>
I suspect this is a bug and have opened a issue:
https://github.com/ionic-team/ionic-v3/issues/976.
and find another issue similar:
https://github.com/ionic-team/ionic/issues/7043
is that a ionic bug / my program bug?
hope to see advice

Answer 1

You haven't added any code so I'm not 100% sure of what you've tried already but try this:
import { ViewController } from 'ionic-angular';
...
ionViewDidEnter() {
this.viewCtrl.setBackButtonText('Some dynamic button text');
}
Edit
Sorry didn't see your Stackblitz example, this works:
import { Component } from '#angular/core';
import { NavController, Config, ViewController } from 'ionic-angular';
#Component({
selector: 'page-contact',
templateUrl: 'contact.html'
})
export class ContactPage {
constructor(public navCtrl: NavController,
public config: Config,
private viewCtrl: ViewController) {
}
toChinese() {
this.viewCtrl.setBackButtonText('返回');
}
toEnglish() {
this.viewCtrl.setBackButtonText('Back');
}
}