bY4tWCtR

1class FingerprintDialog : DialogFragment(), FingerprintController.Callback {
2
3private val controller: FingerprintController by lazy {
4    FingerprintController(
5            FingerprintManagerCompat.from(this.context!!),
6            this,
7            titleTextView,
8            subtitleTextView,
9            errorTextView,
10            iconFAB
11    )
12}
13
14
15private var keyStore: KeyStore? = null
16
17
18private var keyGenerator: KeyGenerator? = null
19
20override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? =
21        inflater.inflate(R.layout.dialog_fingerprint, container, false)
22
23
24override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
25    super.onViewCreated(view!!, savedInstanceState)
26
27    controller.setTitle(arguments!!.getString(ARG_TITLE))
28    controller.setSubtitle(arguments!!.getString(ARG_SUBTITLE))
29}
30
31@RequiresApi(Build.VERSION_CODES.M)
32override fun onCreate(savedInstanceState: Bundle?) {
33    super.onCreate(savedInstanceState)
34
35    try {
36        keyStore = KeyStore.getInstance("AndroidKeyStore")
37    } catch (e: KeyStoreException) {
38        throw RuntimeException("Failed to get an instance of KeyStore", e)
39    }
40
41    try {
42        keyGenerator = KeyGenerator
43                .getInstance(KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore")
44    } catch (e: NoSuchAlgorithmException) {
45        throw RuntimeException("Failed to get an instance of KeyGenerator", e)
46    } catch (e: NoSuchProviderException) {
47        throw RuntimeException("Failed to get an instance of KeyGenerator", e)
48    }
49
50    createKey(DEFAULT_KEY_NAME, false)
51
52    val defaultCipher: Cipher
53    try {
54        defaultCipher = Cipher.getInstance(KeyProperties.KEY_ALGORITHM_AES + "/"
55                + KeyProperties.BLOCK_MODE_CBC + "/"
56                + KeyProperties.ENCRYPTION_PADDING_PKCS7)
57    } catch (e: NoSuchAlgorithmException) {
58        throw RuntimeException("Failed to get an instance of Cipher", e)
59    } catch (e: NoSuchPaddingException) {
60        throw RuntimeException("Failed to get an instance of Cipher", e)
61    }
62
63    if (initCipher(defaultCipher, DEFAULT_KEY_NAME)) {
64        cryptoObject = FingerprintManagerCompat.CryptoObject(defaultCipher)
65    }
66}
67
68override fun onResume() {
69    super.onResume()
70
71    dialog?.window?.setLayout(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)
72    cryptoObject?.let {
73        controller.startListening(it)
74    }
75}
76
77override fun onPause() {
78    super.onPause()
79    controller.stopListening()
80}
81
82override fun onAuthenticated() {
83    //TODO:
84}
85
86override fun onError() {
87    //TODO:
88}
89
90
91@RequiresApi(Build.VERSION_CODES.M)
92private fun initCipher(cipher: Cipher, keyName: String): Boolean {
93    try {
94        keyStore?.load(null)
95        val key = keyStore?.getKey(keyName, null) as SecretKey
96        cipher.init(Cipher.ENCRYPT_MODE, key)
97        return true
98    } catch (e: KeyPermanentlyInvalidatedException) {
99        return false
100    } catch (e: KeyStoreException) {
101        throw RuntimeException("Failed to init Cipher", e)
102    } catch (e: CertificateException) {
103        throw RuntimeException("Failed to init Cipher", e)
104    } catch (e: UnrecoverableKeyException) {
105        throw RuntimeException("Failed to init Cipher", e)
106    } catch (e: IOException) {
107        throw RuntimeException("Failed to init Cipher", e)
108    } catch (e: NoSuchAlgorithmException) {
109        throw RuntimeException("Failed to init Cipher", e)
110    } catch (e: InvalidKeyException) {
111        throw RuntimeException("Failed to init Cipher", e)
112    }
113}
114
115
116@RequiresApi(Build.VERSION_CODES.M)
117private fun createKey(keyName: String, invalidatedByBiometricEnrollment: Boolean) {
118 to set up fingerprint
119    set of
120    // enrolled fingerprints has changed.
121    try {
122        keyStore?.load(null)
123        // Set the alias of the entry in Android KeyStore where the key will appear
124        // and the constrains (purposes) in the constructor of the Builder
125
126        val builder = KeyGenParameterSpec.Builder(keyName,
127                KeyProperties.PURPOSE_ENCRYPT or KeyProperties.PURPOSE_DECRYPT)
128                .setBlockModes(KeyProperties.BLOCK_MODE_CBC)
129                // Require the user to authenticate with a fingerprint to authorize every use
130                // of the key
131                .setUserAuthenticationRequired(true)
132                .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_PKCS7)
133
134        // This is a workaround to avoid crashes on devices whose API level is < 24
135        // because KeyGenParameterSpec.Builder#setInvalidatedByBiometricEnrollment is only
136        // visible on API level +24.
137        // Ideally there should be a compat library for KeyGenParameterSpec.Builder but
138        // which isn't available yet.
139        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
140            builder.setInvalidatedByBiometricEnrollment(invalidatedByBiometricEnrollment)
141        }
142        keyGenerator?.init(builder.build())
143        keyGenerator?.generateKey()
144    } catch (e: NoSuchAlgorithmException) {
145        throw RuntimeException(e)
146    } catch (e: InvalidAlgorithmParameterException) {
147        throw RuntimeException(e)
148    } catch (e: CertificateException) {
149        throw RuntimeException(e)
150    } catch (e: IOException) {
151        throw RuntimeException(e)
152    }
153
154}
155
156companion object {
157
158    fun newInstance(title: String, subtitle: String): FingerprintDialog {
159        val args = Bundle()
160        args.putString(ARG_TITLE, title)
161        args.putString(ARG_SUBTITLE, subtitle)
162
163        val fragment = FingerprintDialog()
164        fragment.arguments = args
165
166        return fragment
167    }
168}
169
170class FingerprintController(private val fingerprintManager: FingerprintManagerCompat, private val callback: Callback, private val title: TextView, private val subtitle: TextView, private val errorText: TextView, private val icon: ImageView) : FingerprintManagerCompat.AuthenticationCallback() {
171
172
173private var cancellationSignal: CancellationSignal? = null
174
175private var selfCancelled = false
176
177
178private val isFingerprintAuthAvailable: Boolean
179    get() = fingerprintManager.isHardwareDetected && fingerprintManager.hasEnrolledFingerprints()
180
181
182private val context: Context
183    get() = errorText.context
184
185
186private val resetErrorTextRunnable: Runnable = Runnable {
187    errorText.setTextColor(ContextCompat.getColor(context, R.color.hint_color))
188    errorText.text = context.getString(R.string.touch_sensor)
189    icon.setImageResource(R.drawable.ic_fingerprint_white_24dp)
190}
191
192init {
193    errorText.post(resetErrorTextRunnable)
194}
195
196
197fun startListening(cryptoObject: FingerprintManagerCompat.CryptoObject) {
198    if (!isFingerprintAuthAvailable) return
199
200    cancellationSignal = CancellationSignal()
201    selfCancelled = false
202    fingerprintManager.authenticate(cryptoObject, 0, cancellationSignal, this, null)
203}
204
205
206fun stopListening() {
207    cancellationSignal?.let {
208        selfCancelled = true
209        it.cancel()
210        cancellationSignal = null
211    }
212}
213
214
215private fun showError(text: CharSequence?) {
216    icon.setImageResource(R.drawable.ic_error_white_24dp)
217    errorText.text = text
218    errorText.setTextColor(ContextCompat.getColor(errorText.context, R.color.warning_color))
219    errorText.removeCallbacks(resetErrorTextRunnable)
220    errorText.postDelayed(resetErrorTextRunnable, ERROR_TIMEOUT_MILLIS)
221}
222
223override fun onAuthenticationError(errMsgId: Int, errString: CharSequence?) {
224    if (!selfCancelled) {
225        showError(errString)
226        icon.postDelayed({
227            callback.onError()
228        }, ERROR_TIMEOUT_MILLIS)
229    }
230}
231
232@RequiresApi(Build.VERSION_CODES.O)
233override fun onAuthenticationSucceeded(result: FingerprintManagerCompat.AuthenticationResult?) {
234    errorText.removeCallbacks(resetErrorTextRunnable)
235    icon.setImageResource(R.drawable.ic_check_white_24dp)
236    errorText.setTextColor(ContextCompat.getColor(errorText.context, R.color.success_color))
237    errorText.text = errorText.context.getString(R.string.fingerprint_recognized)
238    icon.postDelayed({
239        callback.onAuthenticated()
240    }, SUCCESS_DELAY_MILLIS)
241}
242
243override fun onAuthenticationHelp(helpMsgId: Int, helpString: CharSequence?) {
244    showError(helpString)
245}
246
247override fun onAuthenticationFailed() {
248    showError(errorText.context.getString(R.string.fingerprint_not_recognized))
249}
250
251
252fun setTitle(title: CharSequence) {
253    this.title.text = title
254}
255
256
257fun setSubtitle(subtitle: CharSequence) {
258    this.subtitle.text = subtitle
259}
260
261companion object {
262
263    private val ERROR_TIMEOUT_MILLIS = 1600L
264
265
266    private val SUCCESS_DELAY_MILLIS = 1300L
267}
268
269
270interface Callback {
271
272    fun onAuthenticated()
273
274
275    fun onError()
276}