FingerprintHandler.java

package com.sharmaji.fingerprint;

import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.hardware.fingerprint.FingerprintManager;
import android.os.Build;
import android.os.CancellationSignal;
import android.widget.Toast;

import androidx.annotation.RequiresApi;
import androidx.core.app.ActivityCompat;

@RequiresApi(api = Build.VERSION_CODES.M)
class FingerprintHandler extends FingerprintManager.AuthenticationCallback{
    private Context context;

    public FingerprintHandler(Context context) {
        this.context = context;
    }

    @RequiresApi(api = Build.VERSION_CODES.M)
    public void startAuthentication(FingerprintManager fingerprintManager, FingerprintManager.CryptoObject cryptoObject) {

        CancellationSignal cancellationSignal =new CancellationSignal();
        if(ActivityCompat.checkSelfPermission(context, Manifest.permission.USE_FINGERPRINT) != PackageManager.PERMISSION_GRANTED)
            return;
        fingerprintManager.authenticate(cryptoObject,cancellationSignal,0,this,null);
        }

    @Override
    public void onAuthenticationFailed() {
        Toast.makeText(context,"Authenticatio Failed",Toast.LENGTH_LONG).show();
        super.onAuthenticationFailed();
    }

    @Override
    public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
        super.onAuthenticationSucceeded(result);
        context.startActivity(new Intent(context,Homeactivity.class));
    }
}