qr.js

/*export default class App extends Component {
  state = {
    webview: false,
    url: ''
  }
  onSuccess = e => {
    this.setState({url: e.data, webview: true})
  }; */

render() {
  return (
    <View style={{flex:1}}>
        {this.state.webview && (<WebView 
            source={{uri: this.state.url}}
            style={{flex:1}}
            scalesPageToFit={true} />
            )}

       {!this.state.webview && (<QRCodeScanner
          onRead={this.onSuccess.bind(this)}
          reactivate={true}
          reactivateTimeout={4000}/>  
          )}
  )
}