Ionic + Swiper onSlideChange Method

Dear Community,

I use in my HTML:
<ion-button class=“intro-button” (click)=“start()” [hidden]="!disablePrev">Überspringen
<ion-button class=“intro-button” (click)=“prev()” [hidden]=“disablePrev”>Zurück

and in my TS:
disablePrev: boolean = true;
onSlideChange() {
const activeSlide = this.swiper.swiperRef.realIndex;
this.disablePrev = activeSlide === 0;

When i click on the button my Skip Button (Überspringen) get hidden but if i do with touch nothing change.

Why dont change the button btw the renderer component if i use touch?