Question

need help to build a App in Adroid Studio for finger print to secure and lock folder from computer

Answer 1

SOURCE CODE:

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<TextView
android:id="@+id/heading"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:padding="20dp"
android:text="Fingerprint Authentication"
android:textAlignment="center"
android:textColor="@android:color/black"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />

<TextView
android:id="@+id/paraMessage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
android:text="Place your finger on the fingerprint scanner to proceed"
android:textAlignment="center"
android:textColor="@color/colorAccent"
android:textSize="16sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/fingerprint_image_view"
app:layout_constraintVertical_bias="0.178" />

<ImageView
android:id="@+id/fingerprint_image_view"
android:layout_width="110dp"
android:layout_height="119dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/heading"
app:layout_constraintVertical_bias="0.029"
app:srcCompat="@drawable/fingerprint_icon" />
</android.support.constraint.ConstraintLayout>

FingerprintHandler.java (Model class)

import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Context;
import android.hardware.fingerprint.FingerprintManager;
import android.os.Build;
import android.os.CancellationSignal;
import android.support.v4.content.ContextCompat;
import android.widget.ImageView;
import android.widget.TextView;

@TargetApi(Build.VERSION_CODES.M)
public class FingerprintHandler extends FingerprintManager.AuthenticationCallback {

private Context context;

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

public void startAuth(FingerprintManager fingerprintManager, FingerprintManager.CryptoObject cryptoObject)
{
CancellationSignal cancellationSignal = new CancellationSignal();
fingerprintManager.authenticate(cryptoObject, cancellationSignal, 0, this, null);
}

@Override
public void onAuthenticationError(int errorCode, CharSequence errString) {
this.update("There was an auth error: " + errString, false);
}

@Override
public void onAuthenticationFailed() {
this.update("Authentication failed!", false);
}

@Override
public void onAuthenticationHelp(int helpCode, CharSequence helpString) {
this.update("Error: " + helpString, false);
}

@Override
public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
this.update("You can now access the app!", true);
}

public void update(String s, boolean b)
{
TextView paraMessage = (TextView) ((Activity) context).findViewById(R.id.paraMessage);
ImageView fingerPrintImageView = (ImageView) ((Activity) context).findViewById(R.id.fingerprint_image_view);

paraMessage.setText(s);

if(b == false)
{
paraMessage.setTextColor(ContextCompat.getColor(context, R.color.colorPrimary));
}
else
{
paraMessage.setTextColor(ContextCompat.getColor(context, R.color.colorAccent));
fingerPrintImageView.setImageResource(R.drawable.done_icon);
}
}
}

MainActivity.java

import android.Manifest;
import android.app.KeyguardManager;
import android.content.pm.PackageManager;
import android.hardware.fingerprint.FingerprintManager;
import android.os.Build;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

private TextView heading, paraMesaage;
private ImageView fingerPrintImageView;

private FingerprintManager fingerprintManager;
private KeyguardManager keyguardManager;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

heading = (TextView) findViewById(R.id.heading);
paraMesaage = (TextView) findViewById(R.id.paraMessage);
fingerPrintImageView = (ImageView) findViewById(R.id.fingerprint_image_view);

/*
* TODO
* 1. Check: Android version should be greater than Marshmallow
* 2. Check: Device has fingerprint scanner
* 3. Check: Have permissions to use fingerprint scanner in the device
* 4. Check: Lock screen is secured with at least 1 type of lock
* 5. Check: At least 1 fingerprint is registered
/

if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
{
fingerprintManager = (FingerprintManager) getSystemService(FINGERPRINT_SERVICE);
keyguardManager = (KeyguardManager) getSystemService(KEYGUARD_SERVICE);

// Add <uses-permission android:name="android.permission.USE_FINGERPRINT"/>
// this line to AndroidManifest.xml file

if(!fingerprintManager.isHardwareDetected())
{
paraMesaage.setText("Fingerprint Scanner not detected in your device!");
}
else if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.USE_FINGERPRINT)
!= PackageManager.PERMISSION_GRANTED)
{
paraMesaage.setText("Permission not granted to use Fingerprint Scanner!");
}
else if(!keyguardManager.isKeyguardSecure())
{
paraMesaage.setText("Add lock to your device in Device Settings!");
}
else if(!fingerprintManager.hasEnrolledFingerprints())
{
paraMesaage.setText("You should add at least 1 fingerprint to use this feature!");
}
else
{
paraMesaage.setText("Place your finger on the fingerprint scanner to proceed");

FingerprintHandler fingerprintHandler = new FingerprintHandler(MainActivity.this);
fingerprintHandler.startAuth(fingerprintManager, null);
}
}
}
}