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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  */
     31 public class FingerprintUiHelper extends FingerprintManager.AuthenticationCallback {
     32 
     33     @VisibleForTesting static final long ERROR_TIMEOUT_MILLIS = 1600;
     34     @VisibleForTesting static final long SUCCESS_DELAY_MILLIS = 1300;
     35 
     36     private final FingerprintManager mFingerprintManager;
     37     private final ImageView mIcon;
     38     private final TextView mErrorTextView;
     39     private final Callback mCallback;
     40     private CancellationSignal mCancellationSignal;
     41 
     42     @VisibleForTesting boolean mSelfCancelled;
     43 
     44     /**
     45      * Builder class for {@link FingerprintUiHelper} in which injected fields from Dagger
     46      * holds its fields and takes other arguments in the {@link #build} method.
     47      */
     48     public static class FingerprintUiHelperBuilder {
     49         private final FingerprintManager mFingerPrintManager;
     50 
     51         @Inject
     52         public FingerprintUiHelperBuilder(FingerprintManager fingerprintManager) {
     53             mFingerPrintManager = fingerprintManager;
     54         }
     55 
     56         public FingerprintUiHelper build(ImageView icon, TextView errorTextView, Callback callback) {
     57             return new FingerprintUiHelper(mFingerPrintManager, icon, errorTextView,
     58                     callback);
     59         }
     60     }
     61 
     62     /**
     63      * Constructor for {@link FingerprintUiHelper}. This method is expected to be called from
     64      * only the {@link FingerprintUiHelperBuilder} class.
     65      */
     66     private FingerprintUiHelper(FingerprintManager fingerprintManager,
     67             ImageView icon, TextView errorTextView, Callback callback) {
     68         mFingerprintManager = fingerprintManager;
     69         mIcon = icon;
     70         mErrorTextView = errorTextView;
     71         mCallback = callback;
     72     }
     73 
     74     public boolean isFingerprintAuthAvailable() {
     75         return mFingerprintManager.isHardwareDetected()
     76                 && mFingerprintManager.hasEnrolledFingerprints();
     77     }
     78 
     79     public void startListening(FingerprintManager.CryptoObject cryptoObject) {
     80         if (!isFingerprintAuthAvailable()) {
     81             return;
     82         }
     83         mCancellationSignal = new CancellationSignal();
     84         mSelfCancelled = false;
     85         mFingerprintManager
     86                 .authenticate(cryptoObject, mCancellationSignal, 0 /* flags */, this, null);
     87         mIcon.setImageResource(R.drawable.ic_fp_40px);
     88     }
     89 
     90     public void stopListening() {
     91         if (mCancellationSignal != null) {
     92             mSelfCancelled = true;
     93             mCancellationSignal.cancel();
     94             mCancellationSignal = null;
     95         }
     96     }
     97 
     98     @Override
     99     public void onAuthenticationError(int errMsgId, CharSequence errString) {
    100         if (!mSelfCancelled) {
    101             showError(errString);
    102             mIcon.postDelayed(new Runnable() {
    103                 @Override
    104                 public void run() {
    105                     mCallback.onError();
    106                 }
    107             }, ERROR_TIMEOUT_MILLIS);
    108         }
    109     }
    110 
    111     @Override
    112     public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {
    113         showError(helpString);
    114     }
    115 
    116     @Override
    117     public void onAuthenticationFailed() {
    118         showError(mIcon.getResources().getString(
    119                 R.string.fingerprint_not_recognized));
    120     }
    121 
    122     @Override
    123     public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
    124         mErrorTextView.removeCallbacks(mResetErrorTextRunnable);
    125         mIcon.setImageResource(R.drawable.ic_fingerprint_success);
    126         mErrorTextView.setTextColor(
    127                 mErrorTextView.getResources().getColor(R.color.success_color, null));
    128         mErrorTextView.setText(
    129                 mErrorTextView.getResources().getString(R.string.fingerprint_success));
    130         mIcon.postDelayed(new Runnable() {
    131             @Override
    132             public void run() {
    133                 mCallback.onAuthenticated();
    134             }
    135         }, SUCCESS_DELAY_MILLIS);
    136     }
    137 
    138     private void showError(CharSequence error) {
    139         mIcon.setImageResource(R.drawable.ic_fingerprint_error);
    140         mErrorTextView.setText(error);
    141         mErrorTextView.setTextColor(
    142                 mErrorTextView.getResources().getColor(R.color.warning_color, null));
    143         mErrorTextView.removeCallbacks(mResetErrorTextRunnable);
    144         mErrorTextView.postDelayed(mResetErrorTextRunnable, ERROR_TIMEOUT_MILLIS);
    145     }
    146 
    147     @VisibleForTesting
    148     Runnable mResetErrorTextRunnable = new Runnable() {
    149         @Override
    150         public void run() {
    151             mErrorTextView.setTextColor(
    152                     mErrorTextView.getResources().getColor(R.color.hint_color, null));
    153             mErrorTextView.setText(
    154                     mErrorTextView.getResources().getString(R.string.fingerprint_hint));
    155             mIcon.setImageResource(R.drawable.ic_fp_40px);
    156         }
    157     };
    158 
    159     public interface Callback {
    160 
    161         void onAuthenticated();
    162 
    163         void onError();
    164     }
    165 }
    166