How to create Fingerprint Lock using switch to enable/disable the Lock

Question

I want to integrate fingerprint lock into my application. The user has a choice to enable/disable the lock using switch. How can I achieve it programmatically.

For Example something like this:

Choice to enable/disable the lock inside the application

When user opens the application

Answer 1

So I have implemented this type of feature in my app but I don't know whether its a viable feature you may find an easy and sensible method but this is what I do

I use shared preferences for this so first in the activity where https://i.sstatic.net/3FY78.jpg exist I do like below

First I create this method

private void Biometric(){
    androidx.biometric.BiometricManager biometricManager = androidx.biometric.BiometricManager.from(this);
    switch (biometricManager.canAuthenticate(BiometricManager.Authenticators.BIOMETRIC_WEAK | BiometricManager.Authenticators.DEVICE_CREDENTIAL)) {


        // this means we can use biometric sensor
        case androidx.biometric.BiometricManager.BIOMETRIC_SUCCESS:
            SharedPreferences sharedPreferences = getSharedPreferences("Authentication",0);
            SharedPreferences.Editor editor = sharedPreferences.edit();
            editor.putString(TEXT, "1");
            editor.putBoolean(SWITCH1, Swicth_authenticate.isChecked());
            editor.apply();

            Intent intent = new Intent(AboutActivity.this, edit_profile.class);
            intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            startActivity(intent);
            finish();

            break;

        // this means that the device doesn't have fingerprint sensor
        case androidx.biometric.BiometricManager.BIOMETRIC_ERROR_NO_HARDWARE:
            Swicth_authenticate.setChecked(false);
            Toast.makeText(this, "Error code 0x08080101 Authentication failed there's no Fingerprint Reader in your device.", Toast.LENGTH_SHORT).show();
            break;

        // this means that biometric sensor is not available
        case androidx.biometric.BiometricManager.BIOMETRIC_ERROR_HW_UNAVAILABLE:
            Swicth_authenticate.setChecked(false);
            Toast.makeText(this, "Error code 0x08080102 Authentication failed biometric system not found.", Toast.LENGTH_SHORT).show();
            break;

        // this means that the device doesn't contain your fingerprint
        case BiometricManager.BIOMETRIC_ERROR_NONE_ENROLLED:
            Swicth_authenticate.setChecked(false);
            Toast.makeText(this, "Error code 0x08080103 There's no password for this device.", Toast.LENGTH_SHORT).show();
            break;
        case BiometricManager.BIOMETRIC_ERROR_SECURITY_UPDATE_REQUIRED:
            break;
        case BiometricManager.BIOMETRIC_ERROR_UNSUPPORTED:
            break;
        case BiometricManager.BIOMETRIC_STATUS_UNKNOWN:
            break;
    }
}

And Activate the above method whenever a user turns on the checkbox And if user Deactivates I run the following in a method

        SharedPreferences sharedPreferences = getSharedPreferences("Authentication",0);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(TEXT, "0");
        editor.putBoolean(SWITCH1, Swicth_authenticate.isChecked());
        editor.apply();

As you can see I have used Shared Preferences in that method and in my launcher activity I do the following thing.

    SharedPreferences sharedPreferences = getSharedPreferences("Authentication", 0);
        String bio = sharedPreferences.getString(TEXT, "");


        if (bio.equals("1")) {

            BiometricManager biometricManager = androidx.biometric.BiometricManager.from(this);
            switch (biometricManager.canAuthenticate(BiometricManager.Authenticators.BIOMETRIC_WEAK | DEVICE_CREDENTIAL)) {

                // this means we can use biometric sensor
                case BiometricManager.BIOMETRIC_SUCCESS:

                    break;

                // this means that the device doesn't have fingerprint sensor
                case BiometricManager.BIOMETRIC_ERROR_NO_HARDWARE:

                    break;

                // this means that biometric sensor is not available
                case BiometricManager.BIOMETRIC_ERROR_HW_UNAVAILABLE:

                    break;

                // this means that the device doesn't contain your fingerprint
                case BiometricManager.BIOMETRIC_ERROR_NONE_ENROLLED:

                    break;
                case BiometricManager.BIOMETRIC_ERROR_SECURITY_UPDATE_REQUIRED:
                    break;
                case BiometricManager.BIOMETRIC_ERROR_UNSUPPORTED:

                    break;
                case BiometricManager.BIOMETRIC_STATUS_UNKNOWN:

                    break;
            }
            // creating a variable for our Executor
            Executor executor = ContextCompat.getMainExecutor(this);
            // this will give us result of AUTHENTICATION
            final BiometricPrompt biometricPrompt = new BiometricPrompt(StartActivity.this, executor, new BiometricPrompt.AuthenticationCallback() {
                @Override
                public void onAuthenticationError(int errorCode, @NonNull CharSequence errString) {
                    super.onAuthenticationError(errorCode, errString);
                }

                // THIS METHOD IS CALLED WHEN AUTHENTICATION IS SUCCESS
                @Override
                public void onAuthenticationSucceeded(@NonNull BiometricPrompt.AuthenticationResult result) {
                    super.onAuthenticationSucceeded(result);
                    Toast.makeText(getApplicationContext(), "Login Success.", Toast.LENGTH_SHORT).show();
                    Intent intent = new Intent(StartActivity.this, MainActivity.class);
                    startActivity(intent);
                    finish();
                }

                @Override
                public void onAuthenticationFailed() {
                    super.onAuthenticationFailed();
                }
            });
            // creating a variable for our promptInfo
            // BIOMETRIC DIALOG
            final BiometricPrompt.PromptInfo promptInfo = new BiometricPrompt.PromptInfo.Builder().setTitle("Authentication")
                    .setDescription("Use your fingerprint to login ")
                    .setAllowedAuthenticators(BiometricManager.Authenticators.BIOMETRIC_WEAK | DEVICE_CREDENTIAL).build();

            biometricPrompt.authenticate(promptInfo);

        } else {
            Intent intent = new Intent(StartActivity.this, MainActivity.class);
            startActivity(intent);
            finish();
        }

If you have any doubt regarding this comment below I know its very huge but I don't know how much you know so I pretty much wrote whole code even then if you have doubt you can see the following source code https://github.com/MohammedAbidNafi/MessengerByMargs