Отпечаток пальца отменен при использовании в приложении аутентификации

Question

Я использую FingerprintManager в своем приложении для аутентификации пользователя каждый раз, когда он возвращается в приложение после разблокировки экрана. В первый раз он работает нормально, в следующий раз он показывает, что операция снятия отпечатка пальца отменена.

Вот мой код:

public class FingerprintHandler extends FingerprintManager.AuthenticationCallback
{
    private AlertDialog.Builder dialogBuilder;
    private AlertDialog b;

    private TextView text_state;
    private ImageView image_state;
    View view;
    private Context context;

    public FingerprintHandler(Context mContext, View mView) {
        context = mContext;
        this.view = mView;
        dialogBuilder = new AlertDialog.Builder(context);
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        final View dialogView = inflater.inflate(R.layout.custom_fingerprint_auth_dialog, null);
        text_state = (TextView) dialogView.findViewById(R.id.text_state);
        image_state = (ImageView) dialogView.findViewById(R.id.image_state);
       // view = inflater.inflate(R.layout.activity_passcode, null);
        dialogBuilder.setView(dialogView);
        dialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {
                dialog.dismiss();
            }
        });
        dialogBuilder.setPositiveButton("Use Password", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {

                PasscodeActivity.enterPassword(view, context);
            }
        });
        b = dialogBuilder.create();
        b.show();
        b.setCancelable(false);
        b.setCanceledOnTouchOutside(false);
    }

    //Implement the startAuth method, which is responsible for starting the fingerprint authentication process//

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

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

    @Override
    //onAuthenticationError is called when a fatal error has occurred. It provides the error code and error message as its parameters//

    public void onAuthenticationError(int errMsgId, CharSequence errString) {

        //I’m going to display the results of fingerprint authentication as a series of toasts.
        //Here, I’m creating the message that’ll be displayed if an error occurs//

        if (errMsgId != FINGERPRINT_ERROR_CANCELED) {
            text_state.setText(errString);
            Log.e("ERROR", "" + errString);
            image_state.setImageResource(R.drawable.ic_fingerprint_failure);
            text_state.setTextColor(context.getResources().getColor(R.color.notVerified));
            //Toast.makeText(context, "Authentication error\n" + errString, Toast.LENGTH_LONG).show();
        }
    }

    @Override

    //onAuthenticationFailed is called when the fingerprint doesn’t match with any of the fingerprints registered on the device//

    public void onAuthenticationFailed() {
        text_state.setText(context.getString(R.string.fingerFailure));
        image_state.setImageResource(R.drawable.ic_fingerprint_failure);
        text_state.setTextColor(context.getResources().getColor(R.color.notVerified));
        //Toast.makeText(context, "Authentication failed", Toast.LENGTH_LONG).show();
    }

    @Override

    //onAuthenticationHelp is called when a non-fatal error has occurred. This method provides additional information about the error,
    //so to provide the user with as much feedback as possible I’m incorporating this information into my toast//
    public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {
        text_state.setText(helpString);
        Log.e("HELP",""+helpString);
        image_state.setImageResource(R.drawable.ic_fingerprint_failure);
        text_state.setTextColor(context.getResources().getColor(R.color.notVerified));
        //Toast.makeText(context, "Authentication help\n" + helpString, Toast.LENGTH_LONG).show();
    }

    @Override

    //onAuthenticationSucceeded is called when a fingerprint has been successfully matched to one of the fingerprints stored on the user’s device//
    public void onAuthenticationSucceeded(
            FingerprintManager.AuthenticationResult result) {

        text_state.setText(context.getString(R.string.fingerSuccess));
        image_state.setImageResource(R.drawable.ic_fingerprint_success);
        text_state.setTextColor(context.getResources().getColor(R.color.colorPrimaryDark));
        Activity activity = (Activity) context;
        activity.finish();
        b.dismiss();

        //Toast.makeText(context, "Success!", Toast.LENGTH_LONG).show();
    }
}

Answer 1

Операция снятия отпечатка пальца обычно отменяется, когда датчик занят предыдущей операцией. Каждый раз, когда вы выходите из приложения или после завершения аутентификации, звоните cancellationSignal.cancel(); Это обеспечит завершение работы датчика и его разблокировку. В вашем случае я бы добавил эту строку в ваши LockScreens onPause, а также Важно: и эту строку в каждом из ваших обратных вызовов FingerPrintHandler просто для того, чтобы убедиться, например,

    @Override
//onAuthenticationFailed is called when the fingerprint doesn’t match with any of the fingerprints registered on the device//
public void onAuthenticationFailed() {
    text_state.setText(context.getString(R.string.fingerFailure));
    image_state.setImageResource(R.drawable.ic_fingerprint_failure);
    cancellationSignal.cancel();
    text_state.setTextColor(context.getResources().getColor(R.color.notVerified));
    //Toast.makeText(context, "Authentication failed", Toast.LENGTH_LONG).show();
}