Android 中指纹识别

Android从6.0系统开始就支持指纹认证功能了，指纹功能还需要有硬件支持才行

指纹与手机系统设置的指纹进行匹配

如图:

Android 中指纹识别-LMLPHP

在LoginActivity 中弹出指纹验证Fragment，验证成功进入MainActivity中

代码：

创建FingerprintDialogFragment 继承 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;

    /**

     * 标识是否是用户主动取消的认证。

     */

    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();

        // 开始指纹认证监听

        startListening(mCipher);

    }

    @Override

    public void onPause() {

        super.onPause();

        // 停止指纹认证监听

        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, "指纹认证成功", Toast.LENGTH_SHORT).show();

                mActivity.onAuthenticated();

            }

            @Override

            public void onAuthenticationFailed() {

                errorMsg.setText("指纹认证失败，请再试一次");

            }

        }, 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="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>

　　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()) {//判断是否支持指纹

            initKey();

            initCipher();

        }

    }

    /**

     * 判断是否支持指纹

     * @return

     */

    @SuppressLint("MissingPermission")

    public 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 {

            //键盘锁管理者

            KeyguardManager keyguardManager = getSystemService(KeyguardManager.class);

            //指纹管理者

            FingerprintManager fingerprintManager = getSystemService(FingerprintManager.class);

            if (!fingerprintManager.isHardwareDetected()) {//判断硬件支不支持指纹

                Toast.makeText(this, "您的手机不支持指纹功能", Toast.LENGTH_SHORT).show();

                return false;

            } else if (!keyguardManager.isKeyguardSecure()) {//还未设置锁屏

                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()) {//指纹未登记

                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;

    }

    @TargetApi(23)

    private void initKey() {

        try {

            keyStore = KeyStore.getInstance("AndroidKeyStore");

            keyStore.load(null);

            //秘钥生成器

            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="已进入App主界面"

        android:textSize="18sp"

        android:layout_gravity="center"

        />

</FrameLayout>

　　最后添加权限

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

　　注意，通常为了让用户清楚的知道现在需要进行指纹认证，Google官方建议最好使用一个通用的指纹图标，而不应该由各APP制作自己的指纹图标。为此，Google也特意提供了一套指纹认证的组图，可以点击这里查看和下载。

指纹认证不能单独使用，必须要配合着图案或其他认证方式一起来使用，因为一定要提供一个在设备不支持指纹情况下的其他认证方式

另外FingerprintManager在最新的Android 9.0系统上已经被废弃了因为Android 9.0系统提供了更加强大的生物识别认证功能，包括指纹识别、面部识别、甚至是虹膜识别等等，因此仅仅只能用于指纹识别的FingerprintManager已经不能满足新系统的强大需求了。

参考与郭神的https://blog.csdn.net/guolin_blog/article/details/81450114