Alternative for keypress event which will work on mobiles

Question

I want to validate a Textbox using Angular 5 and it should not accept any characters other than numbers.

I have written following code, Its Working on Pc Browser but its not working on Android Mobile Browsers.

Below is my code ,

<mat-form-field fxFlex="20" class="RightInput">
                   <input matInput name="Indication1PatientNo" formControlName="Indication1PatientNo" placeholder="Patient No." (keypress)="_OnlyNumeriCkeyPress($event)">
                 </mat-form-field>

_OnlyNumeriCkeyPress(event: any) {
       const pattern = /[0-9\+\-\ ]/;
       let inputChar = String.fromCharCode(event.charCode);

       if (!pattern.test(inputChar)) {
           // invalid character, prevent input
           event.preventDefault();
       }
   }