Ionic 4 - Camera - Runtime Error - Object(...) is not a function - object

Question

I'm creating an Ionic app with camera function. I used for this the doc from ionic-framework Ionic native camera
But I get an error when I tried to display the app on my Android device and click onto the "Take a Picture" button.
Error
"Runtime Error Object(…) is not a function"
"TypeError: Object(…) is not a function at Camera.getPicture"
home.ts
import { Component } from '#angular/core';
import { NavController, PopoverController, ViewController } from 'ionic-angular';
import { UserServiceProvider } from './../../providers/user-service/user-service';
import { Camera, CameraOptions, DestinationType, EncodingType, MediaType } from '#ionic-native/camera/ngx';
#Component({
selector: 'page-home',
templateUrl: 'home.html',
})
export class HomePage {
constructor(public navCtrl: NavController, public popoverCtrl: PopoverController, private camera:Camera) {}
myPhoto:any=''
takePicture(){
const options: CameraOptions = {
quality:100,
destinationType: this.camera.DestinationType.FILE_URI,
encodingType: this.camera.EncodingType.JPEG,
mediaType: this.camera.MediaType.PICTURE
}
this.camera.getPicture(options).then((imageData)=>{
this.myPhoto=(<any>window).Ionic.WebView.convertFileSrc(imageData);
}, (err) => {
// Error log
});
}
openMoreSetting(event) {
let popover = this.popoverCtrl.create(PopoverPage);
popover.present({
ev: event
});
}
}
#Component({
template: `
<ion-list>
<button ion-item>Menu für Settings</button>
</ion-list>
`
})
export class PopoverPage {
constructor(private userServiceProvider: UserServiceProvider,
private viewCtrl: ViewController) {
}
close() {
this.viewCtrl.dismiss();
}
}