How to use

authenticate

method

in

android.support.v4.hardware.fingerprint.FingerprintManagerCompat

managerCompat.authenticate(null, 0, cancellationSignal, new FingerprintManagerCompat.AuthenticationCallback() {

public void startListening(FingerprintManagerCompat.CryptoObject cryptoObject) {
  if (!isFingerprintAuthAvailable()) {
    return;
  }
  mCancellationSignal = new CancellationSignal();
  mSelfCancelled = false;
  // The line below prevents the false positive inspection from Android Studio
  // noinspection ResourceType
  mFingerprintManager.authenticate(
      cryptoObject, 0, mCancellationSignal, this, null);
  mIcon.setImageResource(R.drawable.ic_fp_40px_pf);
}

public void startListening(FingerprintManagerCompat.CryptoObject cryptoObject) {
  if (!isFingerprintAuthAvailable()) {
    return;
  }
  mCancellationSignal = new CancellationSignal();
  mSelfCancelled = false;
  mFingerprintManager
      .authenticate(cryptoObject, 0 /* flags */, mCancellationSignal, this, null);
  mIcon.setImageResource(R.drawable.ic_fp_40px);
}

  @Override
  public void onClick(View v) {
    // reset result info.
    mResultInfo.setText(R.string.fingerprint_hint);
    mResultInfo.setTextColor(getColor(R.color.hint_color));
    // start fingerprint auth here.
    try {
      CryptoObjectHelper cryptoObjectHelper = new CryptoObjectHelper();
      if (cancellationSignal == null) {
        cancellationSignal = new CancellationSignal();
      }
      fingerprintManager.authenticate(cryptoObjectHelper.buildCryptoObject(), 0,
          cancellationSignal, myAuthCallback, null);
      // set button state.
      mStartBtn.setEnabled(false);
      mCancelBtn.setEnabled(true);
    } catch (Exception e) {
      e.printStackTrace();
      Toast.makeText(MainActivity.this, "Fingerprint init failed! Try again!", Toast.LENGTH_SHORT).show();
    }
  }
});