利用Android6.0怎么实现一个指纹识别功能

 public class FingerprintUtil{ private FingerprintManagerCompat mFingerprintManager; private KeyguardManager mKeyManager; private CancellationSignal mCancellationSignal; private Activity mActivity; public FingerprintUtil(Context ctx) {  mActivity = (Activity) ctx;  mFingerprintManager = FingerprintManagerCompat.from(mActivity);  mKeyManager = (KeyguardManager) mActivity.getSystemService(Context.KEYGUARD_SERVICE); } public void callFingerPrintVerify(final IFingerprintResultListener listener) {  if (!isHardwareDetected()) {   return;  }  if (!isHasEnrolledFingerprints()) {   if (listener != null) {    listener.onNoEnroll();   }   return;  }  if (!isKeyguardSecure()) {   if (listener != null) {    listener.onInSecurity();   }   return;  }  if (listener != null) {   listener.onSupport();  }  if (listener != null) {   listener.onAuthenticateStart();  }  if (mCancellationSignal == null) {   mCancellationSignal = new CancellationSignal();  }  try {   mFingerprintManager.authenticate(null, 0, mCancellationSignal, new FingerprintManagerCompat.AuthenticationCallback() {    //多次尝试都失败会走onAuthenticationError，会停止响应一段时间，提示尝试次数过多，请稍后再试。    @Override    public void onAuthenticationError(int errMsgId, CharSequence errString) {     if (listener != null)      listener.onAuthenticateError(errMsgId, errString);    }    //指纹验证失败走此方法，例如小米前4次验证失败走onAuthenticationFailed,第5次走onAuthenticationError    @Override    public void onAuthenticationFailed() {     if (listener != null)      listener.onAuthenticateFailed();    }    @Override    public void onAuthenticationHelp(int helpMsgId, CharSequence helpString) {     if (listener != null)      listener.onAuthenticateHelp(helpMsgId, helpString);    }    //当验证的指纹成功时会回调此函数，然后不再监听指纹sensor    @Override    public void onAuthenticationSucceeded(FingerprintManagerCompat.AuthenticationResult result) {     if (listener != null)      listener.onAuthenticateSucceeded(result);    }   }, null);  } catch (Exception e) {   e.printStackTrace();  } }  private boolean isHasEnrolledFingerprints() {  try {   return mFingerprintManager.hasEnrolledFingerprints();  } catch (Exception e) {   return false;  } }  public boolean isHardwareDetected() {  try {   return mFingerprintManager.isHardwareDetected();  } catch (Exception e) {   return false;  } }  private boolean isKeyguardSecure() {  try {   return mKeyManager.isKeyguardSecure();  } catch (Exception e) {   return false;  } }  public interface IFingerprintResultListener {  void onInSecurity();  void onNoEnroll();  void onSupport();  void onAuthenticateStart();  void onAuthenticateError(int errMsgId, CharSequence errString);  void onAuthenticateFailed();  void onAuthenticateHelp(int helpMsgId, CharSequence helpString);  void onAuthenticateSucceeded(FingerprintManagerCompat.AuthenticationResult result); } public void cancelAuthenticate() {  if (mCancellationSignal != null) {   mCancellationSignal.cancel();   mCancellationSignal = null;  } } public void onDestroy() {  cancelAuthenticate();  mKeyManager = null;  mFingerprintManager = null; }