Android获取手机已录入指纹信息列表

序言

Android SDK是不开放给普通开发者系统已录入的指纹信息列表的，那当我们需要获取手机系统中已录入指纹信息的时候，应该怎么做呢？

正常的Android指纹识别怎么做

旧版写法使用FingerprintManager

Java 复制代码

private class AuthenticationCallback extends FingerprintManager.AuthenticationCallback {
    @Override
    public void onAuthenticationError(int errorCode, CharSequence errString) {
        super.onAuthenticationError(errorCode, errString);
        Toast.makeText(MainActivity.this, "认证错误：" + errString, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onAuthenticationHelp(int helpCode, CharSequence helpString) {
        super.onAuthenticationHelp(helpCode, helpString);
        Toast.makeText(MainActivity.this, "认证帮助：" + helpString, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
        super.onAuthenticationSucceeded(result);
        Toast.makeText(MainActivity.this, "认证成功", Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onAuthenticationFailed() {
        super.onAuthenticationFailed();
        Toast.makeText(MainActivity.this, "认证失败", Toast.LENGTH_SHORT).show();
    }
}

新版写法使用BiometricManager

java 复制代码

BiometricPrompt.AuthenticationCallback callback = new BiometricPrompt.AuthenticationCallback() {
    @Override
    public void onAuthenticationError(int errorCode, CharSequence errString) {
        super.onAuthenticationError(errorCode, errString);
        // 处理认证错误
    }

    @Override
    public void onAuthenticationSucceeded(BiometricPrompt.AuthenticationResult result) {
        super.onAuthenticationSucceeded(result);
        // 认证成功
        // 在这里可以执行登录逻辑
    }

    @Override
    public void onAuthenticationFailed() {
        super.onAuthenticationFailed();
        // 认证失败
    }
};

对比发现，新的onAuthenticationSucceeded认证成功后返回参数result对象为 BiometricPrompt.AuthenticationResult ，而以前的写法是返回的FingerprintManager.AuthenticationResult

先查看旧版中 FingerprintManager.AuthenticationResult 源码，可以看到类已经@Deprecated，让我们使用新版的android.hardware.biometrics.BiometricPrompt.AuthenticationResult，这里面有个属性是`Fingerprint`类，看着很像是存放指纹信息的内容

java 复制代码

/**
 * Container for callback data from {@link FingerprintManager#authenticate(CryptoObject,
 *     CancellationSignal, int, AuthenticationCallback, Handler)}.
 * @deprecated See {@link android.hardware.biometrics.BiometricPrompt.AuthenticationResult}
 */
@Deprecated
public static class AuthenticationResult {
    private Fingerprint mFingerprint;
    private CryptoObject mCryptoObject;
    private int mUserId;
    private boolean mIsStrongBiometric;

    /**
     * Authentication result
     *
     * @param crypto the crypto object
     * @param fingerprint the recognized fingerprint data, if allowed.
     * @hide
     */
    public AuthenticationResult(CryptoObject crypto, Fingerprint fingerprint, int userId,
            boolean isStrongBiometric) {
        mCryptoObject = crypto;
        mFingerprint = fingerprint;
        mUserId = userId;
        mIsStrongBiometric = isStrongBiometric;
    }

    /**
     * Obtain the crypto object associated with this transaction
     * @return crypto object provided to {@link FingerprintManager#authenticate(CryptoObject,
     *     CancellationSignal, int, AuthenticationCallback, Handler)}.
     */
    public CryptoObject getCryptoObject() { return mCryptoObject; }

    /**
     * Obtain the Fingerprint associated with this operation. Applications are strongly
     * discouraged from associating specific fingers with specific applications or operations.
     *
     * @hide
     */
    @UnsupportedAppUsage
    public Fingerprint getFingerprint() { return mFingerprint; }

    /**
     * Obtain the userId for which this fingerprint was authenticated.
     * @hide
     */
    public int getUserId() { return mUserId; }

    /**
     * Check whether the strength of the fingerprint modality associated with this operation is
     * strong (i.e. not weak or convenience).
     * @hide
     */
    public boolean isStrongBiometric() {
        return mIsStrongBiometric;
    }
}

查看Fingerprint 类源码，Fingerprint 继承于BiometricAuthenticator.Identifier ，这个好像有点眼熟啊，和新版的BiometricPrompt 很像啊，我们先放着，去看看新版BiometricPrompt.AuthenticationResult的源码

java 复制代码

/**
 * Container for fingerprint metadata.
 * @hide
 */
public final class Fingerprint extends BiometricAuthenticator.Identifier {
    private int mGroupId;

    public Fingerprint(CharSequence name, int groupId, int fingerId, long deviceId) {
        super(name, fingerId, deviceId);
        mGroupId = groupId;
    }

    public Fingerprint(CharSequence name, int fingerId, long deviceId) {
        super(name, fingerId, deviceId);
    }

    private Fingerprint(Parcel in) {
        super(in.readString(), in.readInt(), in.readLong());
        mGroupId = in.readInt();
    }

    /**
     * Gets the group id specified when the fingerprint was enrolled.
     * @return group id for the set of fingerprints this one belongs to.
     */
    public int getGroupId() {
        return mGroupId;
    }

    public int describeContents() {
        return 0;
    }

    public void writeToParcel(Parcel out, int flags) {
        out.writeString(getName().toString());
        out.writeInt(getBiometricId());
        out.writeLong(getDeviceId());
        out.writeInt(mGroupId);
    }

    public static final @android.annotation.NonNull Parcelable.Creator<Fingerprint> CREATOR
            = new Parcelable.Creator<Fingerprint>() {
        public Fingerprint createFromParcel(Parcel in) {
            return new Fingerprint(in);
        }

        public Fingerprint[] newArray(int size) {
            return new Fingerprint[size];
        }
    };
}

新版 BiometricPrompt.AuthenticationResult 源码

java 复制代码

public static class AuthenticationResult extends BiometricAuthenticator.AuthenticationResult

从代码来看BiometricPrompt.AuthenticationResult 是继承BiometricAuthenticator.AuthenticationResult 的，这个就和上面的Fingerprint 继承于BiometricAuthenticator.Identifier 联系上了啊，一家人整整齐齐了的，那么继续看BiometricAuthenticator.AuthenticationResult类的源码

java 复制代码

/**
 * Container for callback data from {@link BiometricAuthenticator#authenticate(
 * CancellationSignal, Executor, AuthenticationCallback)} and
 * {@link BiometricAuthenticator#authenticate(CryptoObject, CancellationSignal, Executor,
 * AuthenticationCallback)}
 */
class AuthenticationResult {
    private Identifier mIdentifier;
    private CryptoObject mCryptoObject;
    private @AuthenticationResultType int mAuthenticationType;
    private int mUserId;

    /**
     * @hide
     */
    public AuthenticationResult() { }

    /**
     * Authentication result
     * @param crypto
     * @param authenticationType
     * @param identifier
     * @param userId
     * @hide
     */
    public AuthenticationResult(CryptoObject crypto,
            @AuthenticationResultType int authenticationType, Identifier identifier,
            int userId) {
        mCryptoObject = crypto;
        mAuthenticationType = authenticationType;
        mIdentifier = identifier;
        mUserId = userId;
    }

    /**
     * Provides the crypto object associated with this transaction.
     * @return The crypto object provided to {@link BiometricPrompt#authenticate(
     * BiometricPrompt.CryptoObject, CancellationSignal, Executor,
     * BiometricPrompt.AuthenticationCallback)}
     */
    public CryptoObject getCryptoObject() {
        return mCryptoObject;
    }

    /**
     * Provides the type of authentication (e.g. device credential or biometric) that was
     * requested from and successfully provided by the user.
     *
     * @return An integer value representing the authentication method used.
     */
    public @AuthenticationResultType int getAuthenticationType() {
        return mAuthenticationType;
    }

    /**
     * Obtain the biometric identifier associated with this operation. Applications are strongly
     * discouraged from associating specific identifiers with specific applications or
     * operations.
     * @hide
     */
    public Identifier getId() {
        return mIdentifier;
    }

    /**
     * Obtain the userId for which this biometric was authenticated.
     * @hide
     */
    public int getUserId() {
        return mUserId;
    }
};

BiometricPrompt.AuthenticationResult 类中有Identifier 这个类诶，那这个类和老版本的Fingerprint是一样的作用啊，那仔细再查看下Identifier类的内容

java 复制代码

/**
 * Container for biometric data
 * @hide
 */
abstract class Identifier implements Parcelable {
    private CharSequence mName;
    private int mBiometricId;
    private long mDeviceId; // physical device this is associated with

    public Identifier() {}

    public Identifier(CharSequence name, int biometricId, long deviceId) {
        mName = name;
        mBiometricId = biometricId;
        mDeviceId = deviceId;
    }

    /**
     * Gets the human-readable name for the given biometric.
     * @return name given to the biometric
     */
    public CharSequence getName() {
        return mName;
    }

    /**
     * Gets the device-specific biometric id.  Used by Settings to map a name to a specific
     * biometric template.
     */
    public int getBiometricId() {
        return mBiometricId;
    }

    /**
     * Device this biometric belongs to.
     */
    public long getDeviceId() {
        return mDeviceId;
    }

    public void setName(CharSequence name) {
        mName = name;
    }

    public void setDeviceId(long deviceId) {
        mDeviceId = deviceId;
    }
}

有mBiometricId 生物识别id这个属性, 好像是找到了，但是这个要怎么获取呢？

我们再找找有没有Fingerprint 列表的获取方式，find一下List<Fingerprint>或者 List<BiometricAuthenticator.Identifier>

还真找到了，在 FingerprintManager.java 中有一个方法返回List<Fingerprint>，这个注释看着也像是获取指纹列表啊

java 复制代码

/**
 * Obtain the list of enrolled fingerprints templates.
 * @return list of current fingerprint items
 *
 * @hide
 */
@RequiresPermission(USE_FINGERPRINT)
@UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
public List<Fingerprint> getEnrolledFingerprints(int userId) {
    if (mService != null) try {
            return mService.getEnrolledFingerprints(
                    userId, mContext.getOpPackageName(), mContext.getAttributionTag());
    } catch (RemoteException e) {
        throw e.rethrowFromSystemServer();
    }
    return null;
}