Java tutorial
/* * Copyright (C) 2015 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License */ package com.hyosung.fingerprint; import android.Manifest; import android.annotation.TargetApi; import android.app.Activity; import android.content.pm.PackageManager; 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; /** * Small helper class to manage text/icon around fingerprint authentication UI. */ @TargetApi(Build.VERSION_CODES.M) public class FingerprintUiHelper extends FingerprintManager.AuthenticationCallback { static final long ERROR_TIMEOUT_MILLIS = 1000; static final long SUCCESS_DELAY_MILLIS = 1000; private final FingerprintManager mFingerprintManager; private final ImageView mIcon; private final TextView mErrorTextView; private final FingerprintCallback mCallback; private CancellationSignal mCancellationSignal; private Activity mActivity; /** * Builder class for {@link FingerprintUiHelper} in which injected fields from Dagger * holds its fields and takes other arguments in the {@link #build} method. */ public static class FingerprintUiHelperBuilder { private final FingerprintManager mFingerPrintManager; public FingerprintUiHelperBuilder(FingerprintManager fingerprintManager) { mFingerPrintManager = fingerprintManager; } public FingerprintUiHelper build(Activity activity, ImageView icon, TextView errorTextView, FingerprintCallback callback) { return new FingerprintUiHelper(activity, mFingerPrintManager, icon, errorTextView, callback); } } /** * Constructor for {@link FingerprintUiHelper}. This method is expected to be called from * only the {@link FingerprintUiHelperBuilder} class. */ private FingerprintUiHelper(Activity activity, FingerprintManager fingerprintManager, ImageView icon, TextView errorTextView, FingerprintCallback callback) { mActivity = activity; mFingerprintManager = fingerprintManager; mIcon = icon; mErrorTextView = errorTextView; mCallback = callback; } public void startListening(FingerprintManager.CryptoObject cryptoObject) { if (cryptoObject == null) return; mCancellationSignal = new CancellationSignal(); if (ContextCompat.checkSelfPermission(mActivity, Manifest.permission.USE_FINGERPRINT) == PackageManager.PERMISSION_GRANTED) { mFingerprintManager.authenticate(cryptoObject, mCancellationSignal, 0 /* flags */, this, null); } mIcon.setImageResource(R.drawable.ic_fp_40px); } public void stopListening() { if (mCancellationSignal != null) { mCancellationSignal.cancel(); mCancellationSignal = null; } } @Override public void onAuthenticationError(final int errMsgId, CharSequence errString) { showError(errString); mIcon.postDelayed(new Runnable() { @Override public void run() { mCallback.onError(errMsgId); } }, ERROR_TIMEOUT_MILLIS); } @Override public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) { showError(helpString); } @Override public void onAuthenticationFailed() { showError(mIcon.getResources().getString(R.string.fingerprint_not_recognized)); } @Override public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) { mErrorTextView.removeCallbacks(mResetErrorTextRunnable); mIcon.setImageResource(R.drawable.ic_fingerprint_success); mErrorTextView .setTextColor(mErrorTextView.getResources().getColor(R.color.fingerprint_success_color, null)); mErrorTextView.setText(mErrorTextView.getResources().getString(R.string.fingerprint_success)); mIcon.postDelayed(new Runnable() { @Override public void run() { mCallback.onAuthenticated(); } }, SUCCESS_DELAY_MILLIS); } private void showError(CharSequence error) { mIcon.setImageResource(R.drawable.ic_fingerprint_error); mErrorTextView.setText(error); mErrorTextView .setTextColor(mErrorTextView.getResources().getColor(R.color.fingerprint_warning_color, null)); mErrorTextView.removeCallbacks(mResetErrorTextRunnable); mErrorTextView.postDelayed(mResetErrorTextRunnable, ERROR_TIMEOUT_MILLIS); } Runnable mResetErrorTextRunnable = new Runnable() { @Override public void run() { mErrorTextView .setTextColor(mErrorTextView.getResources().getColor(R.color.fingerprint_hint_color, null)); mErrorTextView.setText(mErrorTextView.getResources().getString(R.string.fingerprint_hint)); mIcon.setImageResource(R.drawable.ic_fp_40px); } }; }