FingerPrint identification

Hi,
I try to implement the fingerprint identification on my app, but I don’t get Something : how to let the fingerprint scanner always on ?

Here is my code :

  async componentDidMount(){
       if (this.state.fingerprintSupport){
           await this.scanFinger();
       }
  }

  async scanFinger() {
      this.setState({ waitingFingerprint: true });

            let result = await Fingerprint.authenticateAsync('Waiting for TouchID');
            if (result.success) {
                ToastAndroid.show('Success !', ToastAndroid.SHORT);
                this.setState({ waitingFingerprint: false });
                this.props.navigation.navigate('App');
            }else {
                ToastAndroid.show('Echec de l\'authentification !', ToastAndroid.SHORT);
                this.setState({fingerprintFailedMsg: 'Unknown', waitingFingerprint: false,});
                // await this.scanFinger();
        }
    }


If it is a succes for the first time, then it works, but if the first scan is not a success, then I can’t start again, and I must input a password.
How can I fix it please ?

Hi there @spoutnik97 - which platform are you seeing this issue on?

It may be an OS-level restriction that Expo cannot do anything about - i.e. the OS forces you to put in your password if the fingerprint scan fails. Do you see this type of behavior in other apps that ask you to scan fingerprints?

It is on Android.
Indeed, as soon as the fingerprint fails one time, I can’t retry it. So I must include a button to relaunch the scan. It is not very convenient…
It seems that on the Lydia app for example I can retry to scan my fingerprint at less three times

Moreover, frequently the scan is processed automatically before I can put my finger on the sensor, so it is a fail, and I can’t try to identicate me at all

I think this is due to a bad core API from android. I opened a canny -> https://expo.canny.io/feature-requests/p/fingerprint-scanner-auto-reset-on-android and I’ll let our android devs know whats up :smiley:

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