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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License
     15  */
     16 
     17 package com.example.android.asymmetricfingerprintdialog;
     18 
     19 import com.google.common.annotations.VisibleForTesting;
     20 
     21 import android.hardware.fingerprint.FingerprintManager;
     22 import android.os.CancellationSignal;
     23 import android.widget.ImageView;
     24 import android.widget.TextView;
     25 
     26 import javax.inject.Inject;
     27 
     28 /**
     29  * Small helper class to manage text/icon around fingerprint authentication UI.
     30  * This class assumes that the {@link android.Manifest.permission#USE_FINGERPRINT}
     31  * permission has already been granted. (As of API 23 this permission is normal instead of dangerous
     32  * and is granted at install time.)
     33  */
     34 @SuppressWarnings("MissingPermission")
     35 public class FingerprintUiHelper extends FingerprintManager.AuthenticationCallback {
     36 
     37     @VisibleForTesting static final long ERROR_TIMEOUT_MILLIS = 1600;
     38     @VisibleForTesting static final long SUCCESS_DELAY_MILLIS = 1300;
     39 
     40     private final FingerprintManager mFingerprintManager;
     41     private final ImageView mIcon;
     42     private final TextView mErrorTextView;
     43     private final Callback mCallback;
     44     private CancellationSignal mCancellationSignal;
     45 
     46     @VisibleForTesting boolean mSelfCancelled;
     47 
     48     /**
     49      * Builder class for {@link FingerprintUiHelper} in which injected fields from Dagger
     50      * holds its fields and takes other arguments in the {@link #build} method.
     51      */
     52     public static class FingerprintUiHelperBuilder {
     53         private final FingerprintManager mFingerPrintManager;
     54 
     55         @Inject
     56         public FingerprintUiHelperBuilder(FingerprintManager fingerprintManager) {
     57             mFingerPrintManager = fingerprintManager;
     58         }
     59 
     60         public FingerprintUiHelper build(ImageView icon, TextView errorTextView, Callback callback) {
     61             return new FingerprintUiHelper(mFingerPrintManager, icon, errorTextView,
     62                     callback);
     63         }
     64     }
     65 
     66     /**
     67      * Constructor for {@link FingerprintUiHelper}. This method is expected to be called from
     68      * only the {@link FingerprintUiHelperBuilder} class.
     69      */
     70     private FingerprintUiHelper(FingerprintManager fingerprintManager,
     71             ImageView icon, TextView errorTextView, Callback callback) {
     72         mFingerprintManager = fingerprintManager;
     73         mIcon = icon;
     74         mErrorTextView = errorTextView;
     75         mCallback = callback;
     76     }
     77 
     78     public boolean isFingerprintAuthAvailable() {
     79         return mFingerprintManager.isHardwareDetected()
     80                 && mFingerprintManager.hasEnrolledFingerprints();
     81     }
     82 
     83     public void startListening(FingerprintManager.CryptoObject cryptoObject) {
     84         if (!isFingerprintAuthAvailable()) {
     85             return;
     86         }
     87         mCancellationSignal = new CancellationSignal();
     88         mSelfCancelled = false;
     89         mFingerprintManager
     90                 .authenticate(cryptoObject, mCancellationSignal, 0 /* flags */, this, null);
     91         mIcon.setImageResource(R.drawable.ic_fp_40px);
     92     }
     93 
     94     public void stopListening() {
     95         if (mCancellationSignal != null) {
     96             mSelfCancelled = true;
     97             mCancellationSignal.cancel();
     98             mCancellationSignal = null;
     99         }
    100     }
    101 
    102     @Override
    103     public void onAuthenticationError(int errMsgId, CharSequence errString) {
    104         if (!mSelfCancelled) {
    105             showError(errString);
    106             mIcon.postDelayed(new Runnable() {
    107                 @Override
    108                 public void run() {
    109                     mCallback.onError();
    110                 }
    111             }, ERROR_TIMEOUT_MILLIS);
    112         }
    113     }
    114 
    115     @Override
    116     public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {
    117         showError(helpString);
    118     }
    119 
    120     @Override
    121     public void onAuthenticationFailed() {
    122         showError(mIcon.getResources().getString(
    123                 R.string.fingerprint_not_recognized));
    124     }
    125 
    126     @Override
    127     public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
    128         mErrorTextView.removeCallbacks(mResetErrorTextRunnable);
    129         mIcon.setImageResource(R.drawable.ic_fingerprint_success);
    130         mErrorTextView.setTextColor(
    131                 mErrorTextView.getResources().getColor(R.color.success_color, null));
    132         mErrorTextView.setText(
    133                 mErrorTextView.getResources().getString(R.string.fingerprint_success));
    134         mIcon.postDelayed(new Runnable() {
    135             @Override
    136             public void run() {
    137                 mCallback.onAuthenticated();
    138             }
    139         }, SUCCESS_DELAY_MILLIS);
    140     }
    141 
    142     private void showError(CharSequence error) {
    143         mIcon.setImageResource(R.drawable.ic_fingerprint_error);
    144         mErrorTextView.setText(error);
    145         mErrorTextView.setTextColor(
    146                 mErrorTextView.getResources().getColor(R.color.warning_color, null));
    147         mErrorTextView.removeCallbacks(mResetErrorTextRunnable);
    148         mErrorTextView.postDelayed(mResetErrorTextRunnable, ERROR_TIMEOUT_MILLIS);
    149     }
    150 
    151     @VisibleForTesting
    152     Runnable mResetErrorTextRunnable = new Runnable() {
    153         @Override
    154         public void run() {
    155             mErrorTextView.setTextColor(
    156                     mErrorTextView.getResources().getColor(R.color.hint_color, null));
    157             mErrorTextView.setText(
    158                     mErrorTextView.getResources().getString(R.string.fingerprint_hint));
    159             mIcon.setImageResource(R.drawable.ic_fp_40px);
    160         }
    161     };
    162 
    163     public interface Callback {
    164 
    165         void onAuthenticated();
    166 
    167         void onError();
    168     }
    169 }
    170