Android 中指紋識別

Android從6.0系統開始就支持指紋認證功能了，指紋功能還需要有硬件支持才行

指紋與手機系統設置的指紋進行匹配

如圖:

在LoginActivity 中彈出指紋驗證Fragment，驗證成功進入MainActivity中

代碼：

創建FingerprintDialogFragment 繼承 DialogFragment

package com.chuanye.zhiwendemo;

import android.annotation.SuppressLint;
import android.content.Context;
import android.hardware.fingerprint.FingerprintManager;
import android.os.Bundle;
import android.os.CancellationSignal;
import android.support.annotation.Nullable;
import android.support.v4.app.DialogFragment;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;

import javax.crypto.Cipher;

public class FingerprintDialogFragment extends DialogFragment {

    private FingerprintManager fingerprintManager;

    private CancellationSignal mCancellationSignal;

    private Cipher mCipher;

    private LoginActivity mActivity;

    private TextView errorMsg;

    /**
     * 標識是否是用戶主動取消的認證。
     */
    private boolean isSelfCancelled;

    public void setCipher(Cipher cipher) {
        mCipher = cipher;
    }

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        mActivity = (LoginActivity) getActivity();
    }

    @SuppressLint("NewApi")
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        fingerprintManager = getContext().getSystemService(FingerprintManager.class);
        setStyle(DialogFragment.STYLE_NORMAL, android.R.style.Theme_Material_Light_Dialog);
    }

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, 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();
                stopListening();
            }
        });
        return v;
    }

    @Override
    public void onResume() {
        super.onResume();
        // 開始指紋認證監聽
        startListening(mCipher);
    }

    @Override
    public void onPause() {
        super.onPause();
        // 停止指紋認證監聽
        stopListening();
    }

    @SuppressLint({"MissingPermission", "NewApi"})
    private void startListening(Cipher cipher) {
        isSelfCancelled = false;
        mCancellationSignal = new CancellationSignal();
        fingerprintManager.authenticate(new FingerprintManager.CryptoObject(cipher), mCancellationSignal, 0, new FingerprintManager.AuthenticationCallback() {
            @Override
            public void onAuthenticationError(int errorCode, CharSequence errString) {
                if (!isSelfCancelled) {
                    errorMsg.setText(errString);
                    if (errorCode == FingerprintManager.FINGERPRINT_ERROR_LOCKOUT) {
                        Toast.makeText(mActivity, errString, Toast.LENGTH_SHORT).show();
                        dismiss();
                    }
                }
            }

            @Override
            public void onAuthenticationHelp(int helpCode, CharSequence helpString) {
                errorMsg.setText(helpString);
            }

            @Override
            public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
                Toast.makeText(mActivity, "指紋認證成功", Toast.LENGTH_SHORT).show();
                mActivity.onAuthenticated();
            }

            @Override
            public void onAuthenticationFailed() {
                errorMsg.setText("指紋認證失敗，請再試一次");
            }
        }, null);
    }

    @SuppressLint("NewApi")
    private void stopListening() {
        if (mCancellationSignal != null) {
            mCancellationSignal.cancel();
            mCancellationSignal = null;
            isSelfCancelled = true;
        }
    }

}

　　布局

<?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="請驗證指紋解鎖"
        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>

　　LoginActivity 中

package com.chuanye.zhiwendemo;

import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.KeyguardManager;
import android.content.Intent;
import android.hardware.fingerprint.FingerprintManager;
import android.os.Build;
import android.security.keystore.KeyGenParameterSpec;
import android.security.keystore.KeyProperties;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;

import java.security.KeyStore;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

public class LoginActivity extends AppCompatActivity {
    //https://blog.csdn.net/guolin_blog/article/details/81450114

    private static final String DEFAULT_KEY_NAME = "default_key";

    KeyStore keyStore;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);

        if (supportFingerprint()) {//判斷是否支持指紋
            initKey();
            initCipher();
        }
    }

    /**
     * 判斷是否支持指紋
     * @return
     */
    @SuppressLint("MissingPermission")
    public boolean supportFingerprint() {
        if (Build.VERSION.SDK_INT < 23) {
            Toast.makeText(this, "您的系統版本過低，不支持指紋功能", Toast.LENGTH_SHORT).show();
            return false;
        } else {
            //鍵盤鎖管理者
            KeyguardManager keyguardManager = getSystemService(KeyguardManager.class);
            //指紋管理者
            FingerprintManager fingerprintManager = getSystemService(FingerprintManager.class);
            if (!fingerprintManager.isHardwareDetected()) {//判斷硬件支不支持指紋
                Toast.makeText(this, "您的手機不支持指紋功能", Toast.LENGTH_SHORT).show();
                return false;
            } else if (!keyguardManager.isKeyguardSecure()) {//還未設置鎖屏
                Toast.makeText(this, "您還未設置鎖屏，請先設置鎖屏並添加一個指紋", Toast.LENGTH_SHORT).show();
                return false;
            } else if (!fingerprintManager.hasEnrolledFingerprints()) {//指紋未登記
                Toast.makeText(this, "您至少需要在系統設置中添加一個指紋", Toast.LENGTH_SHORT).show();
                return false;
            }
        }
        return true;
    }

    @TargetApi(23)
    private void initKey() {
        try {
            keyStore = KeyStore.getInstance("AndroidKeyStore");
            keyStore.load(null);
            //秘鑰生成器
            KeyGenerator keyGenerator = KeyGenerator.getInstance(KeyProperties.KEY_ALGORITHM_AES, "AndroidKeyStore");
            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);
            keyGenerator.init(builder.build());
            keyGenerator.generateKey();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    @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);
        }
    }

    private void showFingerPrintDialog(Cipher cipher) {
        FingerprintDialogFragment fragment = new FingerprintDialogFragment();
        fragment.setCipher(cipher);
        fragment.show(getSupportFragmentManager(), "fingerprint");
    }

    public void onAuthenticated() {
        Intent intent = new Intent(this, MainActivity.class);
        startActivity(intent);
        finish();
    }

}

　　activity_main.xml布局

<?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">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="已進入App主界面"
        android:textSize="18sp"
        android:layout_gravity="center"
        />

</FrameLayout>

　　最后添加權限

<uses-permission android:name="android.permission.USE_FINGERPRINT"></uses-permission>

　　注意，通常為了讓用戶清楚的知道現在需要進行指紋認證，Google官方建議最好使用一個通用的指紋圖標，而不應該由各APP制作自己的指紋圖標。為此，Google也特意提供了一套指紋認證的組圖，可以 點擊這里 查看和下載。

指紋認證不能單獨使用，必須要配合着圖案或其他認證方式一起來使用，因為一定要提供一個在設備不支持指紋情況下的其他認證方式

另外FingerprintManager在最新的Android 9.0系統上已經被廢棄了因為Android 9.0系統提供了更加強大的生物識別認證功能，包括指紋識別、面部識別、甚至是虹膜識別等等，因此僅僅只能用於指紋識別的FingerprintManager已經不能滿足新系統的強大需求了。

 

參考與郭神的https://blog.csdn.net/guolin_blog/article/details/81450114