Applying Fingerprint Login in android

In android API level 23 i.e. Android Marshmallow, Google introduced Fingerprint authentication. It not only enables the user to unlock the device using figerprint but also have developer’s APIs using which the developers can add the functionality to their own applications and its pretty simple as well.

For Fingerprint login you have to check the hardware support on the device, whether the lock is enable and lastly that there should be at-least one fingerprint stored on the device then you can pop user to authenticate the fingerprint. Ans I can tell you its quiet simple just follow me and you will be able to do this in your application as well.

Firstly you need a login activity like I have

public class LoginActivity extends Activity {
    public Editor editor;
    Object response = null;
    ProgressBar spinner;
    SharedPreferences app_shared;
    ProgressDialog progressDialog;
    AlertDialog forgotPasswordDialog;
    LinearLayout container;
    boolean fingerprint_enabled, fingerprintsupported = false;
    boolean Authenticated = false;
    private ProgressDialog progress;
    private String email, password;
    int NORMAL_REQUEST= -1;
    int CHANGE_REQUEST= 1;

    DialogInterface onCancelDialog = new DialogInterface() {
        @Override
        public void cancel() {
            Login();
        }

        @Override
        public void dismiss() {
            Login();
        }
    };

    @Override
    public void onBackPressed() {
        super.onBackPressed();
        startActivity(new Intent(this, HomeActivity.class).setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));
        this.finish();
    }

    @Override
    protected void onResume() {
        super.onResume();
        invalidateOptionsMenu();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        super.onCreateOptionsMenu(menu);
        return true;
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (ActivityCompat.checkSelfPermission(this,
                    android.Manifest.permission.USE_FINGERPRINT) !=
                    PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.USE_FINGERPRINT}, -1);
            } else {
                fingerprintsupported = gotPermission();
            }
        }
        app_shared = getSharedPreferences("shared", MODE_PRIVATE);
        fingerprint_enabled = app_shared.getBoolean("FingetprintEnabled", false);
        container = (LinearLayout) findViewById(R.id.container);
        spinner = (ProgressBar) findViewById(R.id.loginprogress);
        spinner.setVisibility(View.GONE);
        if (fingerprintsupported && fingerprint_enabled) {
            findViewById(R.id.login_through_fp).setVisibility(View.VISIBLE);
            FingerprintDemoFragment fragment = FingerprintDemoFragment.newInstance(1, NORMAL_REQUEST);
            fragment.show(getSupportFragmentManager(), "tag");
        }
    }

    public void onClickFingerPrintButton(View v){
        FingerprintDemoFragment fragment = FingerprintDemoFragment.newInstance(1, NORMAL_REQUEST);
        fragment.show(getSupportFragmentManager(), "tag");
    }

    public void loginPost(View v) {
        progress = ProgressDialog.show(LoginActivity.this, getResources().getString(R.string.please_wait),
                getResources().getString(R.string.processing_request_response), true);
        progress.setCanceledOnTouchOutside(false);
            if (fingerprintsupported) {
                if (fingerprint_enabled) {
                    if(!app_shared.getString("TouchEmail","").equals(email) || !app_shared.getString("TouchPassword","").equals(password)) {
                        AlertDialog fingerprintDialog = new AlertDialog.Builder(this)
                                .setMessage("Do you want to replace previous credentials with these ones, for Fingerprint authentication?").setCancelable(false)
                                .setPositiveButton(android.R.string.ok, new OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) {
                                        dialog.dismiss();
                                        app_shared.edit().remove("TouchEmail").remove("TouchPassword").apply();
                                        FingerprintDemoFragment  fragment = FingerprintDemoFragment.newInstance(0, CHANGE_REQUEST);
                                        fragment.show(getSupportFragmentManager(), "tag");
                                        fragment.onCancel(onCancelDialog);
                                    }
                                }).setNegativeButton(android.R.string.cancel, new OnClickListener() {
                                    @Override
                                    public void onClick(DialogInterface dialog, int which) {
                                        dialog.dismiss();
                                        Login();
                                    }
                                }).create();
                        fingerprintDialog.show();
                    }else {
                        Login();
                    }
                } else {
                    FingerprintDemoFragment  fragment = FingerprintDemoFragment.newInstance(0, NORMAL_REQUEST);
                    fragment.show(getSupportFragmentManager(), "tag");
                    fragment.onCancel(onCancelDialog);
                }
            } else {
                Login();
            }
        }
    }
   
    public void FingerPrintResult(boolean response, int requestCode) {
        Authenticated = response;
        if (Authenticated) {
            if(requestCode == NORMAL_REQUEST) {
                if (!app_shared.contains("TouchEmail")) {
                    app_shared.edit().putString("TouchEmail", userNameField.getText().toString().trim())
                            .putString("TouchPassword", passwordField.getText().toString().trim()).apply();
                } else {
                    email = app_shared.getString("TouchEmail", "");
                    password = app_shared.getString("TouchPassword", "");
                }
            }else{
                app_shared.edit().putString("TouchEmail", userNameField.getText().toString().trim())
                        .putString("TouchPassword", passwordField.getText().toString().trim()).apply();
            }
            progress = ProgressDialog.show(LoginActivity.this, getResources().getString(R.string.please_wait),
                    getResources().getString(R.string.processing_request_response), true);
            progress.setCanceledOnTouchOutside(false);
            Login();
        }else{
            progress.dismiss();
        }

    }


    @RequiresApi(23)
    public boolean gotPermission(){
        try {
            FingerprintManager fingerprintManager = (FingerprintManager) getSystemService(Context.FINGERPRINT_SERVICE);
            return (fingerprintManager.isHardwareDetected() && fingerprintManager.hasEnrolledFingerprints());
        }catch (SecurityException e){
            e.printStackTrace();
        }
    }

    @TargetApi(23)
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case -1:
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    fingerprintsupported = gotPermission();
                }
                break;
            default:
                break;
        }
    }

    public void Login() {
        // login function
    }
}

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public class LoginActivity extends Activity {

public Editor editor;

Object response = null;

ProgressBar spinner;

SharedPreferences app_shared;

ProgressDialog progressDialog;

AlertDialog forgotPasswordDialog;

LinearLayout container;

boolean fingerprint_enabled, fingerprintsupported = false;

boolean Authenticated = false;

private ProgressDialog progress;

private String email, password;

int NORMAL_REQUEST= -1;

int CHANGE_REQUEST= 1;

DialogInterface onCancelDialog = new DialogInterface() {

@Override

public void cancel() {

}

@Override

public void dismiss() {

}

};

@Override

public void onBackPressed() {

super.onBackPressed();

startActivity(new Intent(this, HomeActivity.class).setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP));

this.finish();

}

@Override

protected void onResume() {

super.onResume();

invalidateOptionsMenu();

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

super.onCreateOptionsMenu(menu);

return true;

}

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_login);

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

if (ActivityCompat.checkSelfPermission(this,

android.Manifest.permission.USE_FINGERPRINT) !=

PackageManager.PERMISSION_GRANTED) {

ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.USE_FINGERPRINT}, -1);

} else {

fingerprintsupported = gotPermission();

}

app_shared = getSharedPreferences("shared", MODE_PRIVATE);

fingerprint_enabled = app_shared.getBoolean("FingetprintEnabled", false);

container = (LinearLayout) findViewById(R.id.container);

spinner = (ProgressBar) findViewById(R.id.loginprogress);

spinner.setVisibility(View.GONE);

if (fingerprintsupported && fingerprint_enabled) {

findViewById(R.id.login_through_fp).setVisibility(View.VISIBLE);

FingerprintDemoFragment fragment = FingerprintDemoFragment.newInstance(1, NORMAL_REQUEST);

fragment.show(getSupportFragmentManager(), "tag");

}

public void onClickFingerPrintButton(View v){

FingerprintDemoFragment fragment = FingerprintDemoFragment.newInstance(1, NORMAL_REQUEST);

fragment.show(getSupportFragmentManager(), "tag");

}

public void loginPost(View v) {

progress = ProgressDialog.show(LoginActivity.this, getResources().getString(R.string.please_wait),

getResources().getString(R.string.processing_request_response), true);

progress.setCanceledOnTouchOutside(false);

if (fingerprintsupported) {

if (fingerprint_enabled) {

if(!app_shared.getString("TouchEmail","").equals(email) || !app_shared.getString("TouchPassword","").equals(password)) {

AlertDialog fingerprintDialog = new AlertDialog.Builder(this)

.setMessage("Do you want to replace previous credentials with these ones, for Fingerprint authentication?").setCancelable(false)

.setPositiveButton(android.R.string.ok, new OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {

dialog.dismiss();

app_shared.edit().remove("TouchEmail").remove("TouchPassword").apply();

FingerprintDemoFragment fragment = FingerprintDemoFragment.newInstance(0, CHANGE_REQUEST);

fragment.show(getSupportFragmentManager(), "tag");

fragment.onCancel(onCancelDialog);

}

}).setNegativeButton(android.R.string.cancel, new OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {

dialog.dismiss();

}

}).create();

fingerprintDialog.show();

}else {

}

} else {

FingerprintDemoFragment fragment = FingerprintDemoFragment.newInstance(0, NORMAL_REQUEST);

fragment.show(getSupportFragmentManager(), "tag");

fragment.onCancel(onCancelDialog);

}

} else {

}

public void FingerPrintResult(boolean response, int requestCode) {

Authenticated = response;

if (Authenticated) {

if(requestCode == NORMAL_REQUEST) {

if (!app_shared.contains("TouchEmail")) {

app_shared.edit().putString("TouchEmail", userNameField.getText().toString().trim())

.putString("TouchPassword", passwordField.getText().toString().trim()).apply();

} else {

email = app_shared.getString("TouchEmail", "");

password = app_shared.getString("TouchPassword", "");

}

}else{

app_shared.edit().putString("TouchEmail", userNameField.getText().toString().trim())

.putString("TouchPassword", passwordField.getText().toString().trim()).apply();

}

progress = ProgressDialog.show(LoginActivity.this, getResources().getString(R.string.please_wait),

getResources().getString(R.string.processing_request_response), true);

progress.setCanceledOnTouchOutside(false);

}else{

progress.dismiss();

}

@RequiresApi(23)

public boolean gotPermission(){

try {

FingerprintManager fingerprintManager = (FingerprintManager) getSystemService(Context.FINGERPRINT_SERVICE);

return (fingerprintManager.isHardwareDetected() && fingerprintManager.hasEnrolledFingerprints());

}catch (SecurityException e){

e.printStackTrace();

}

@TargetApi(23)

@Override

public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {

super.onRequestPermissionsResult(requestCode, permissions, grantResults);

switch (requestCode) {

case -1:

if (grantResults.length > 0

&& grantResults[0] == PackageManager.PERMISSION_GRANTED) {

fingerprintsupported = gotPermission();

}

break;

default:

break;

}

public void Login() {

// login function

}

The XML for the LoginActivity is as below:

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:scrollbars="none">

        <LinearLayout
            android:id="@+id/container"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <TextView
                android:id="@+id/loginFormHeading"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/loginFormHeading"
                android:textAppearance="?android:attr/textAppearanceLarge"/>

            <TextView
                android:id="@+id/loginFormSubHeading"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginBottom="8dp"
                android:text="@string/loginFormSubHeading"/>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="5dp"
                android:background="@color/white"
                android:orientation="vertical"
                android:padding="5dp">

                <TextView
                    android:id="@+id/email_tv"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="@string/email"
                    android:textAppearance="?android:attr/textAppearanceMedium"/>

                <EditText
                    android:id="@+id/username"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:ems="10"
                    android:hint="@string/loginFormEmailTitle"
                    android:inputType="textEmailAddress"
                    android:padding="8dp"/>

                <TextView
                    android:id="@+id/password_tv"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="5dp"
                    android:text="@string/password"
                    android:textAppearance="?android:attr/textAppearanceMedium"/>

                <EditText
                    android:id="@+id/password"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:ems="10"
                    android:hint="@string/password_"
                    android:inputType="textPassword"
                    android:padding="8dp"/>

            </LinearLayout>

            <Button
                android:id="@+id/login"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:background="@color/secondary_color"
                android:onClick="loginPost"
                android:text="@string/loginFormSignInButton"
                android:textColor="@color/white"
                android:textSize="@dimen/Button_textSize"/>
        </LinearLayout>


    </ScrollView>

    <ImageView
        android:id="@+id/login_through_fp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone"
        android:layout_alignParentBottom="true"
        android:onClick="onClickFingerPrintButton"
        android:layout_centerHorizontal="true"
        android:src="@drawable/ic_fp_40px"/>

    <ProgressBar
        android:id="@+id/loginprogress"
        style="\?android:attr/progressBarStyle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerInParent="true"
        android:translationZ="2dp"/>

</RelativeLayout>

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<RelativeLayout

xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:paddingBottom="@dimen/activity_vertical_margin"

android:paddingLeft="@dimen/activity_horizontal_margin"

android:paddingRight="@dimen/activity_horizontal_margin"

android:paddingTop="@dimen/activity_vertical_margin">

<ScrollView

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:scrollbars="none">

<LinearLayout

android:id="@+id/container"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="vertical">

<TextView

android:id="@+id/loginFormHeading"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@string/loginFormHeading"

android:textAppearance="?android:attr/textAppearanceLarge"/>

<TextView

android:id="@+id/loginFormSubHeading"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginBottom="8dp"

android:text="@string/loginFormSubHeading"/>

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="5dp"

android:background="@color/white"

android:orientation="vertical"

android:padding="5dp">

<TextView

android:id="@+id/email_tv"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:text="@string/email"

android:textAppearance="?android:attr/textAppearanceMedium"/>

<EditText

android:id="@+id/username"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:ems="10"

android:hint="@string/loginFormEmailTitle"

android:inputType="textEmailAddress"

android:padding="8dp"/>

<TextView

android:id="@+id/password_tv"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginTop="5dp"

android:text="@string/password"

android:textAppearance="?android:attr/textAppearanceMedium"/>

<EditText

android:id="@+id/password"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:ems="10"

android:hint="@string/password_"

android:inputType="textPassword"

android:padding="8dp"/>

</LinearLayout>

<Button

android:id="@+id/login"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:background="@color/secondary_color"

android:onClick="loginPost"

android:text="@string/loginFormSignInButton"

android:textColor="@color/white"

android:textSize="@dimen/Button_textSize"/>

</LinearLayout>

</ScrollView>

<ImageView

android:id="@+id/login_through_fp"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:visibility="gone"

android:layout_alignParentBottom="true"

android:onClick="onClickFingerPrintButton"

android:layout_centerHorizontal="true"

android:src="@drawable/ic_fp_40px"/>

<ProgressBar

android:id="@+id/loginprogress"

style="\?android:attr/progressBarStyle"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_centerHorizontal="true"

android:layout_centerInParent="true"

android:translationZ="2dp"/>

</RelativeLayout>

The xml for the DailogFragment signin_using_fingerprint.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:app="http://schemas.android.com/apk/res-auto"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_gravity="center_horizontal"
              android:gravity="center_horizontal"
              android:layout_height="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:text="Login"
        android:layout_marginBottom="20dp"
        android:padding="20dp"
        android:gravity="center"
        android:textSize="@dimen/heading_size_medium"
        android:background="@color/secondary_color"
        android:textColor="@color/white"
        android:layout_height="wrap_content"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_marginTop="20dp"
        android:textColor="@color/black"
        android:textSize="@dimen/text_size_medium"
        android:text="Start Using Your FingerPrint"
        android:layout_height="wrap_content"/>


    <ImageView android:layout_width="wrap_content"
               android:layout_marginTop="20dp"
               app:srcCompat="@drawable/finger_print"
               android:layout_height="wrap_content"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_marginTop="20dp"
        android:textSize="@dimen/Button_textSize"
        android:text="Authenticate with your Fingerprint"
        android:layout_marginBottom="20dp"
        android:layout_height="wrap_content"/>


</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:app="http://schemas.android.com/apk/res-auto"

android:orientation="vertical"

android:layout_width="match_parent"

android:layout_gravity="center_horizontal"

android:gravity="center_horizontal"

android:layout_height="match_parent">

<TextView

android:layout_width="match_parent"

android:text="Login"

android:layout_marginBottom="20dp"

android:padding="20dp"

android:gravity="center"

android:textSize="@dimen/heading_size_medium"

android:background="@color/secondary_color"

android:textColor="@color/white"

android:layout_height="wrap_content"/>

<TextView

android:layout_width="wrap_content"

android:layout_marginTop="20dp"

android:textColor="@color/black"

android:textSize="@dimen/text_size_medium"

android:text="Start Using Your FingerPrint"

android:layout_height="wrap_content"/>

<ImageView android:layout_width="wrap_content"

android:layout_marginTop="20dp"

app:srcCompat="@drawable/finger_print"

android:layout_height="wrap_content"/>

<TextView

android:layout_width="wrap_content"

android:layout_marginTop="20dp"

android:textSize="@dimen/Button_textSize"

android:text="Authenticate with your Fingerprint"

android:layout_marginBottom="20dp"

android:layout_height="wrap_content"/>

</LinearLayout>

add_fingerprint_login.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              xmlns:app="http://schemas.android.com/apk/res-auto"
              android:orientation="vertical"
              android:layout_width="match_parent"
              android:layout_gravity="center_horizontal"
              android:gravity="center_horizontal"
              android:layout_height="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:text="ADD FINGERPRINT"
        android:layout_marginBottom="20dp"
        android:padding="20dp"
        android:gravity="center"
        android:textSize="@dimen/heading_size_medium"
        android:background="@color/secondary_color"
        android:textColor="@color/white"
        android:layout_height="wrap_content"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_marginTop="20dp"
        android:textColor="@color/black"
        android:textSize="@dimen/text_size_medium"
        android:text="Start Using Your FingerPrint"
        android:layout_height="wrap_content"/>


    <ImageView android:layout_width="wrap_content"
               android:layout_marginTop="20dp"
               app:srcCompat="@drawable/finger_print"
               android:layout_height="wrap_content"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_marginTop="20dp"
        android:layout_marginBottom="20dp"
        android:textSize="@dimen/Button_textSize"
        android:text="Touch the sensor"
        android:layout_height="wrap_content"/>

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:app="http://schemas.android.com/apk/res-auto"

android:orientation="vertical"

android:layout_width="match_parent"

android:layout_gravity="center_horizontal"

android:gravity="center_horizontal"

android:layout_height="match_parent">

<TextView

android:layout_width="match_parent"

android:text="ADD FINGERPRINT"

android:layout_marginBottom="20dp"

android:padding="20dp"

android:gravity="center"

android:textSize="@dimen/heading_size_medium"

android:background="@color/secondary_color"

android:textColor="@color/white"

android:layout_height="wrap_content"/>

<TextView

android:layout_width="wrap_content"

android:layout_marginTop="20dp"

android:textColor="@color/black"

android:textSize="@dimen/text_size_medium"

android:text="Start Using Your FingerPrint"

android:layout_height="wrap_content"/>

<ImageView android:layout_width="wrap_content"

android:layout_marginTop="20dp"

app:srcCompat="@drawable/finger_print"

android:layout_height="wrap_content"/>

<TextView

android:layout_width="wrap_content"

android:layout_marginTop="20dp"

android:layout_marginBottom="20dp"

android:textSize="@dimen/Button_textSize"

android:text="Touch the sensor"

android:layout_height="wrap_content"/>

</LinearLayout>

Finally the FragmentDialog

public class FingerprintDemoFragment extends BottomSheetDialogFragment implements FingerprintHandler.Callback {

    private static final String KEY_NAME = "fuhdschbaksu";
    FingerprintManager fingerprintManager;
    KeyguardManager keyguardManager;
    private KeyStore keyStore;
    KeyGenerator keyGenerator;
    private Cipher cipher;
    FingerprintManager.CryptoObject cryptoObject;
    static int requestCode;

    public FingerprintDemoFragment() {
    }

    public static FingerprintDemoFragment newInstance(int tag, int req) {
        FingerprintDemoFragment frag = new FingerprintDemoFragment();
        requestCode = req;
        Bundle argsBundle = new Bundle();
        argsBundle.putInt("tag", tag);
        frag.setArguments(argsBundle);
        return frag;
    }

    @Override
    public void setupDialog(Dialog dialog, int style) {
        super.setupDialog(dialog, style);
        View contentView;
        if(getArguments()!=null && getArguments().getInt("tag")==1) {
            contentView = View.inflate(getContext(), R.layout.signin_using_fingerprint, null);
        }else
            contentView = View.inflate(getContext(), R.layout.add_fingerprint_login, null);
        dialog.setContentView(contentView);
        CoordinatorLayout.LayoutParams layoutParams =
                (CoordinatorLayout.LayoutParams) ((View) contentView.getParent()).getLayoutParams();
        CoordinatorLayout.Behavior behavior = layoutParams.getBehavior();
        if (behavior != null && behavior instanceof BottomSheetBehavior) {
            ((BottomSheetBehavior) behavior).setBottomSheetCallback(mBottomSheetBehaviorCallback);
        }
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            Context mcontext = getActivity();
            //initializing keyguard and fingerprint manager
            keyguardManager =
                    (KeyguardManager) mcontext.getSystemService(KEYGUARD_SERVICE);
            fingerprintManager =
                    (FingerprintManager) mcontext.getSystemService(FINGERPRINT_SERVICE);

            //check whether keyguard is enabled or not
            if (!keyguardManager.isKeyguardSecure()) {

                Toast.makeText(mcontext,
                        "Lock screen security not enabled in Settings",
                        Toast.LENGTH_LONG).show();
                return;
            }

            //check whether fingerprint lock is enabled or not
            if (ActivityCompat.checkSelfPermission(mcontext,
                    android.Manifest.permission.USE_FINGERPRINT) !=
                    PackageManager.PERMISSION_GRANTED) {
                return;
            }

            //check whether fingerprint is registered or not
            if (!fingerprintManager.hasEnrolledFingerprints()) {

                // This happens when no fingerprints are registered.
                Toast.makeText(mcontext,
                        "Register at least one fingerprint in Settings",
                        Toast.LENGTH_LONG).show();
                return;
            }
            generateKey();
            if (cipherInit()) {
                cryptoObject = new FingerprintManager.CryptoObject(cipher);
                FingerprintHandler handler = new FingerprintHandler(mcontext, this);
                handler.startAuth(fingerprintManager, cryptoObject);
            }
        }
    }

    private BottomSheetBehavior.BottomSheetCallback mBottomSheetBehaviorCallback = new BottomSheetBehavior.BottomSheetCallback() {

        @Override
        public void onStateChanged(@NonNull View bottomSheet, int newState) {
            if (newState == BottomSheetBehavior.STATE_HIDDEN) {
                dismiss();
            }
        }

        @Override
        public void onSlide(@NonNull View bottomSheet, float slideOffset) {
        }
    };

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

    }

    protected void generateKey() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            //keystore instance needed for getting key access
            try {
                keyStore = KeyStore.getInstance("AndroidKeyStore");
            } catch (Exception e) {
                e.printStackTrace();
            }

            // key generater for generating new key
            try {
                keyGenerator = KeyGenerator.getInstance(
                        KeyProperties.KEY_ALGORITHM_AES,
                        "AndroidKeyStore");
            } catch (NoSuchAlgorithmException |
                    NoSuchProviderException e) {
                throw new RuntimeException(
                        "Failed to get KeyGenerator instance", e);
            }

            // generating key
            try {
                keyStore.load(null);
                keyGenerator.init(new
                        KeyGenParameterSpec.Builder(KEY_NAME,
                        KeyProperties.PURPOSE_ENCRYPT |
                                KeyProperties.PURPOSE_DECRYPT)
                        .setBlockModes(KeyProperties.BLOCK_MODE_CBC)
                        .setUserAuthenticationRequired(true)
                        .setEncryptionPaddings(
                                KeyProperties.ENCRYPTION_PADDING_PKCS7)
                        .build());
                keyGenerator.generateKey();
            } catch (NoSuchAlgorithmException | InvalidAlgorithmParameterException
                    | CertificateException | IOException e) {
                throw new RuntimeException(e);
            }
        }
    }

    @TargetApi(23)
    public boolean cipherInit() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            try {
                cipher = Cipher.getInstance(
                        KeyProperties.KEY_ALGORITHM_AES + "/"
                                + KeyProperties.BLOCK_MODE_CBC + "/"
                                + KeyProperties.ENCRYPTION_PADDING_PKCS7);
            } catch (NoSuchAlgorithmException |
                    NoSuchPaddingException e) {
                throw new RuntimeException("Failed to get Cipher", e);
            }
            try {
                keyStore.load(null);
                SecretKey key = (SecretKey) keyStore.getKey(KEY_NAME,
                        null);
                cipher.init(Cipher.ENCRYPT_MODE, key);
                return true;
            } catch (KeyPermanentlyInvalidatedException e) {
                return false;
            } catch (KeyStoreException | CertificateException
                    | UnrecoverableKeyException | IOException
                    | NoSuchAlgorithmException | InvalidKeyException e) {
                throw new RuntimeException("Failed to init Cipher", e);
            }
        }
        return false;
    }

    @Override
    public void onAuthenticated() {
        ((LoginActivity) getActivity()).FingerPrintResult(true, requestCode);
        dismiss();
    }

    @Override
    public void onError() {
        Toast.makeText(getActivity(),"Authentication Failed",Toast.LENGTH_LONG).show();
        ((LoginActivity) getActivity()).FingerPrintResult(false, requestCode);
        dismiss();
    }
}

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public class FingerprintDemoFragment extends BottomSheetDialogFragment implements FingerprintHandler.Callback {

private static final String KEY_NAME = "fuhdschbaksu";

FingerprintManager fingerprintManager;

KeyguardManager keyguardManager;

private KeyStore keyStore;

KeyGenerator keyGenerator;

private Cipher cipher;

FingerprintManager.CryptoObject cryptoObject;

static int requestCode;

public FingerprintDemoFragment() {

}

public static FingerprintDemoFragment newInstance(int tag, int req) {

FingerprintDemoFragment frag = new FingerprintDemoFragment();

requestCode = req;

Bundle argsBundle = new Bundle();

argsBundle.putInt("tag", tag);

frag.setArguments(argsBundle);

return frag;

}

@Override

public void setupDialog(Dialog dialog, int style) {

super.setupDialog(dialog, style);

View contentView;

if(getArguments()!=null && getArguments().getInt("tag")==1) {

contentView = View.inflate(getContext(), R.layout.signin_using_fingerprint, null);

}else

contentView = View.inflate(getContext(), R.layout.add_fingerprint_login, null);

dialog.setContentView(contentView);

CoordinatorLayout.LayoutParams layoutParams =

(CoordinatorLayout.LayoutParams) ((View) contentView.getParent()).getLayoutParams();

CoordinatorLayout.Behavior behavior = layoutParams.getBehavior();

if (behavior != null && behavior instanceof BottomSheetBehavior) {

((BottomSheetBehavior) behavior).setBottomSheetCallback(mBottomSheetBehaviorCallback);

}

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

Context mcontext = getActivity();

//initializing keyguard and fingerprint manager

keyguardManager =

(KeyguardManager) mcontext.getSystemService(KEYGUARD_SERVICE);

fingerprintManager =

(FingerprintManager) mcontext.getSystemService(FINGERPRINT_SERVICE);

//check whether keyguard is enabled or not

if (!keyguardManager.isKeyguardSecure()) {

Toast.makeText(mcontext,

"Lock screen security not enabled in Settings",

Toast.LENGTH_LONG).show();

return;

}

//check whether fingerprint lock is enabled or not

if (ActivityCompat.checkSelfPermission(mcontext,

android.Manifest.permission.USE_FINGERPRINT) !=

PackageManager.PERMISSION_GRANTED) {

return;

}

//check whether fingerprint is registered or not

if (!fingerprintManager.hasEnrolledFingerprints()) {

// This happens when no fingerprints are registered.

Toast.makeText(mcontext,

"Register at least one fingerprint in Settings",

Toast.LENGTH_LONG).show();

return;

}

generateKey();

if (cipherInit()) {

cryptoObject = new FingerprintManager.CryptoObject(cipher);

FingerprintHandler handler = new FingerprintHandler(mcontext, this);

handler.startAuth(fingerprintManager, cryptoObject);

}

private BottomSheetBehavior.BottomSheetCallback mBottomSheetBehaviorCallback = new BottomSheetBehavior.BottomSheetCallback() {

@Override

public void onStateChanged(@NonNull View bottomSheet, int newState) {

if (newState == BottomSheetBehavior.STATE_HIDDEN) {

dismiss();

}

@Override

public void onSlide(@NonNull View bottomSheet, float slideOffset) {

}

};

@Override

public void onViewCreated(View view, Bundle savedInstanceState) {

super.onViewCreated(view, savedInstanceState);

}

protected void generateKey() {

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

//keystore instance needed for getting key access

try {

keyStore = KeyStore.getInstance("AndroidKeyStore");

} catch (Exception e) {

e.printStackTrace();

}

// key generater for generating new key

try {

keyGenerator = KeyGenerator.getInstance(

KeyProperties.KEY_ALGORITHM_AES,

"AndroidKeyStore");

} catch (NoSuchAlgorithmException |

NoSuchProviderException e) {

throw new RuntimeException(

"Failed to get KeyGenerator instance", e);

}

// generating key

try {

keyStore.load(null);

keyGenerator.init(new

KeyGenParameterSpec.Builder(KEY_NAME,

KeyProperties.PURPOSE_ENCRYPT |

KeyProperties.PURPOSE_DECRYPT)

.setBlockModes(KeyProperties.BLOCK_MODE_CBC)

.setUserAuthenticationRequired(true)

.setEncryptionPaddings(

KeyProperties.ENCRYPTION_PADDING_PKCS7)

.build());

keyGenerator.generateKey();

} catch (NoSuchAlgorithmException | InvalidAlgorithmParameterException

| CertificateException | IOException e) {

throw new RuntimeException(e);

}

@TargetApi(23)

public boolean cipherInit() {

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {

try {

cipher = Cipher.getInstance(

KeyProperties.KEY_ALGORITHM_AES + "/"

+ KeyProperties.BLOCK_MODE_CBC + "/"

+ KeyProperties.ENCRYPTION_PADDING_PKCS7);

} catch (NoSuchAlgorithmException |

NoSuchPaddingException e) {

throw new RuntimeException("Failed to get Cipher", e);

}

try {

keyStore.load(null);

SecretKey key = (SecretKey) keyStore.getKey(KEY_NAME,

null);

cipher.init(Cipher.ENCRYPT_MODE, key);

return true;

} catch (KeyPermanentlyInvalidatedException e) {

return false;

} catch (KeyStoreException | CertificateException

| UnrecoverableKeyException | IOException

| NoSuchAlgorithmException | InvalidKeyException e) {

throw new RuntimeException("Failed to init Cipher", e);

}

return false;

}

@Override

public void onAuthenticated() {

((LoginActivity) getActivity()).FingerPrintResult(true, requestCode);

dismiss();

}

@Override

public void onError() {

Toast.makeText(getActivity(),"Authentication Failed",Toast.LENGTH_LONG).show();

((LoginActivity) getActivity()).FingerPrintResult(false, requestCode);

dismiss();

}

class FingerprintHandler extends FingerprintManager.AuthenticationCallback {

    CancellationSignal Signal;
    private Context appContext;
    private Callback mCallback;

    public FingerprintHandler(Context context, Callback callback) {
        appContext = context;
        mCallback = callback;
    }

    public void startAuth(FingerprintManager manager,
                          FingerprintManager.CryptoObject cryptoObject) {

        Signal = new CancellationSignal();

        if (ActivityCompat.checkSelfPermission(appContext,
                Manifest.permission.USE_FINGERPRINT) !=
                PackageManager.PERMISSION_GRANTED) {
            return;
        }
        manager.authenticate(cryptoObject, Signal, 0, this, null);
    }

    @Override
    public void onAuthenticationError(int errMsgId, CharSequence errString) {
    }

    @Override
    public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {
    }

    @Override
    public void onAuthenticationFailed() {
        mCallback.onError();
    }

    @Override
    public void onAuthenticationSucceeded(
            FingerprintManager.AuthenticationResult result) {
        SharedPreferences app_shared = appContext.getSharedPreferences("App_Data", Context.MODE_PRIVATE);
        if (!app_shared.getBoolean("FingetprintEnabled", false))
            app_shared.edit().putBoolean("FingetprintEnabled", true).apply();
        mCallback.onAuthenticated();
    }

    interface Callback {
        void onAuthenticated();
        void onError();
    }
}

class FingerprintHandler extends FingerprintManager.AuthenticationCallback {

CancellationSignal Signal;

private Context appContext;

private Callback mCallback;

public FingerprintHandler(Context context, Callback callback) {

appContext = context;

mCallback = callback;

}

public void startAuth(FingerprintManager manager,

FingerprintManager.CryptoObject cryptoObject) {

Signal = new CancellationSignal();

if (ActivityCompat.checkSelfPermission(appContext,

Manifest.permission.USE_FINGERPRINT) !=

PackageManager.PERMISSION_GRANTED) {

return;

}

manager.authenticate(cryptoObject, Signal, 0, this, null);

}

@Override

public void onAuthenticationError(int errMsgId, CharSequence errString) {

}

@Override

public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {

}

@Override

public void onAuthenticationFailed() {

mCallback.onError();

}

@Override

public void onAuthenticationSucceeded(

FingerprintManager.AuthenticationResult result) {

SharedPreferences app_shared = appContext.getSharedPreferences("App_Data", Context.MODE_PRIVATE);

if (!app_shared.getBoolean("FingetprintEnabled", false))

app_shared.edit().putBoolean("FingetprintEnabled", true).apply();

mCallback.onAuthenticated();

}

interface Callback {

void onAuthenticated();

void onError();

}

And here you go. Now your app supports fingerprint like other apps.

Source: http://www.techotopia.com/index.php/An_Android_Fingerprint_Authentication_Tutorial

Android app

Aastha 18 December 2016

. . .

1 comments

Shubham Agarwal Nov 21, 2016 at 10:45 pm

Nice codebase.

Applying Fingerprint Login in android

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