FingerPrint identification

#1

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 ?

#2

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?

#3

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

#4

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

#5

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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closed #6

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