版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/qq_35189116/article/details/88368283
前言:
2019年的第一篇博客我们来看看Android系统中指纹识别,在很长一段时间以来指纹识别这一独特用户验证方式都存在于我们的智能手机当中,直到最近一年才慢慢推出了人脸识别等更加高级的生物识别方式,作为Android开发者来讲,可能很多人都不了解它的实现方式,因为确实如果你不是系统开发人员是很少会去接触这个,所以可能会认为是不是要通过第三方的SDK来实现,其实官方SDK在6.0(api23)及以上系统中就提供了相关方法。可能很多人会问那6.0以前手机也有这个功能啊,那只是各大手机厂商改动了Android系统源码来实现该功能。下面通过一个demo来一起学习下.
具体实现:
一,登录逻辑:
首先来看看登录activity逻辑,代码注释的也比较清楚了,值得注意的是记得加入下面的权限
<uses-permission android:name="android.permission.USE_FINGERPRINT" />
public class LoginActivity extends AppCompatActivity{ private static final String DEFAULT_KEY_NAME = "default_key"; //声明密钥库 private KeyStore keyStore; @Override protected void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_login); //确保当前支持指纹识别操作 if(supportFingerprint()){ initKey(); initCipher(); } } @TargetApi(23) private void initCipher() { try { SecretKey key = (SecretKey) keyStore.getKey(DEFAULT_KEY_NAME, null); Cipher cipher = Cipher.getInstance(KeyProperties.KEY_ALGORITHM_AES + "/" + KeyProperties.BLOCK_MODE_CBC + "/" + KeyProperties.ENCRYPTION_PADDING_PKCS7); cipher.init(Cipher.ENCRYPT_MODE,key); showFingerPrintDialog(cipher); }catch (Exception e){ throw new RuntimeException(e); } } @TargetApi(23) private void initKey() { try { //初始化密码库 keyStore = KeyStore.getInstance("AndroidKeyStore"); //加载密码库 keyStore.load(null); //获取密钥生成器 KeyGenerator keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore"); /** * 创建一个参数集 */ KeyGenParameterSpec.Builder builder = new KeyGenParameterSpec.Builder(DEFAULT_KEY_NAME, KeyProperties.PURPOSE_ENCRYPT | KeyProperties.PURPOSE_DECRYPT) .setBlockModes(KeyProperties.BLOCK_MODE_CBC) .setUserAuthenticationRequired(true) .setEncryptionPaddings(KeyProperties.ENCRYPTION_PADDING_PKCS7); //用指定的参数集初始化此密钥生成器。 keyGenerator.init(builder.build()); //生成一个密钥。 keyGenerator.generateKey(); }catch (Exception e){ throw new RuntimeException(e); } } private void showFingerPrintDialog(Cipher cipher) { FingerprintDialogFragment fragment = new FingerprintDialogFragment(); fragment.setCipher(cipher); fragment.show(getSupportFragmentManager(), "fingerprint"); } private boolean supportFingerprint() { if(Build.VERSION.SDK_INT < 23){ Toast.makeText(this, "您的系统版本过低,不支持指纹功能", Toast.LENGTH_SHORT).show(); return false; }else { //键盘管理器 KeyguardManager keyguardManager = getSystemService(KeyguardManager.class); FingerprintManager fingerprintManager = getSystemService(FingerprintManager.class); if(!fingerprintManager.isHardwareDetected()){ Toast.makeText(this, "您的手机不支持指纹功能", Toast.LENGTH_SHORT).show(); return false; }else if(!keyguardManager.isKeyguardSecure()) { Toast.makeText(this, "您还未设置锁屏,请先设置锁屏并添加一个指纹", Toast.LENGTH_SHORT).show(); return false; }else if(!fingerprintManager.hasEnrolledFingerprints()){ Toast.makeText(this, "您至少需要在系统设置中添加一个指纹", Toast.LENGTH_SHORT).show(); return false; } } return true; } public void onAuthenticated() { //验证成功进入主页(这里就不贴出主页代码了,因为不是重点,喜欢怎样写就怎样) Intent intent = new Intent(this, MainActivity.class); startActivity(intent); finish(); } } 登录布局界面很简单(装载一个DialogFragment):
<?xml version="1.0" encoding="utf-8"?> <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" > </FrameLayout>
二,验证逻辑:
通过一个DialogFragment来实现指纹验证过程,代码注释也比较齐全了,
@TargetApi(23) public class FingerprintDialogFragment extends DialogFragment{ //声明指纹管理器 private FingerprintManager fingerprintManager; private LoginActivity mActivity; private TextView errorMsg; //声明密码类(此类为加密和解密提供密码功能) private Cipher mCipher; /** * 标识是否是用户主动取消的认证。 */ private boolean isSelfCancelled; //声明取消信号对象(这个对象是用来维护取消操作的,这些操作包括取消监听和设定取消回调等。) private CancellationSignal mCancellationSignal; @Override public void onAttach(Context context) { super.onAttach(context); mActivity = ((LoginActivity) getActivity()); } public void setCipher(Cipher cipher) { mCipher = cipher; } @Override public void onCreate(@Nullable Bundle savedInstanceState) { super.onCreate(savedInstanceState); //初始化指纹管理器 fingerprintManager = getContext().getSystemService(FingerprintManager.class); setStyle(DialogFragment.STYLE_NORMAL,android.R.style.Theme_Material_Light_Dialog); setCancelable(false); } @Nullable @Override public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { View v = inflater.inflate(R.layout.fingerprint_dialog, container, false); errorMsg = v.findViewById(R.id.error_msg); TextView cancel = v.findViewById(R.id.cancel); cancel.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { dismiss(); //用户指定取消 stopListening(); } }); return v; } @Override public void onResume() { super.onResume(); //开始指纹认证监听 startListening(mCipher); } private void startListening(Cipher cipher) { isSelfCancelled = false; //初始化取消信号对象 mCancellationSignal = new CancellationSignal(); /** * 请求加密对象的身份验证 * 参数一:与调用关联的参数加密对象,如果不需要,则为空。 * 参数二:取消可用于取消身份验证的对象 * 参数三:标志可选标志;应为0 * 参数四:回调对象以接收身份验证事件 * 参数五:处理程序处理回调事件的可选处理程序 */ fingerprintManager.authenticate(new FingerprintManager.CryptoObject(cipher), mCancellationSignal, 0, new FingerprintManager.AuthenticationCallback() { //认证错误 @Override public void onAuthenticationError(int errorCode, CharSequence errString) { super.onAuthenticationError(errorCode, errString); //如果不是用户自己取消 if(!isSelfCancelled){ //显示错误信息 errorMsg.setText(errString); //由于尝试次数太多,API被锁定,操作被取消,这发生在5次失败的尝试之后,持续30秒。就退出 if (errorCode == FingerprintManager.FINGERPRINT_ERROR_LOCKOUT){ Toast.makeText(mActivity, errString, Toast.LENGTH_SHORT).show(); dismiss(); } } } //认证帮助 @Override public void onAuthenticationHelp(int helpCode, CharSequence helpString) { super.onAuthenticationHelp(helpCode, helpString); errorMsg.setText(helpString); } //认证成功 @Override public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) { super.onAuthenticationSucceeded(result); Toast.makeText(mActivity, "指纹认证成功", Toast.LENGTH_SHORT).show(); //认证成功进入主界面 mActivity.onAuthenticated(); } //认证失败 @Override public void onAuthenticationFailed() { super.onAuthenticationFailed(); errorMsg.setText("指纹认证失败,请再试一次"); } },null); } @Override public void onPause() { super.onPause(); //界面失去焦点时停止指纹认证监听 stopListening(); } private void stopListening() { if(mCancellationSignal != null){ //*取消操作并向取消侦听器发送信号。 //*如果操作尚未启动,则一旦启动,它将被取消。 mCancellationSignal.cancel(); mCancellationSignal = null; //用户自取消 isSelfCancelled = true; } } }
Fragment界面xml也简单:
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent"> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:src="@drawable/ic_fp_40px" /> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="20dp" android:text="请验证指纹解锁" android:textColor="#000" android:textSize="16sp" /> <TextView android:id="@+id/error_msg" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center" android:layout_marginTop="5dp" android:maxLines="1" android:textSize="12sp" android:textColor="#f45" /> <View android:layout_width="match_parent" android:layout_height="0.5dp" android:layout_marginTop="10dp" android:background="#ccc" /> <TextView android:id="@+id/cancel" android:layout_width="match_parent" android:layout_height="50dp" android:gravity="center" android:text="取消" android:textColor="#5d7883" android:textSize="16sp" /> </LinearLayout>
效果展示
好了,整体就是这些了。希望能给大家带来帮助。