Android 指纹识别的基本介绍
近期项目中有指纹识别的需求,没接触过,查阅API发现指纹识别是从Android 6.0新增的,也就是必须API版本至少要23以上,要通过指纹扫描验证用户身份,请获取新 FingerprintManager 类的实例,并调用 authenticate() 方法。您的应用必须运行在带有指纹传感器的兼容设备上。您必须在应用中实现指纹身份验证流的用户界面,并在
UI 中使用标准 Android 指纹图标。
1.使用时必须首先判断API版本,先得到系统的API版本:
- minSdkVersion= Build.VERSION.SDK;
2.判断设备是否支持指纹权限:
- manager = (FingerprintManager) getSystemService(Context.FINGERPRINT_SERVICE);
- keyManager= (KeyguardManager) getSystemService(Context.KEYGUARD_SERVICE);
- //硬件设备是否支持指纹解锁功能
- if (!manager.isHardwareDetected()) {
- Toast.makeText(getBaseContext(), "该手机不支持指纹解锁", Toast.LENGTH_SHORT).show();
- return false;
- }
3.还有就是权限,这个也是6.0之后新增的权限:
- <uses-permission
- android:name="android.permission.USE_FINGERPRINT" />
4.接下来就是指纹识别了:
主要就是FingerprintManager.AuthenticationCallback的几个回调:
onAuthenticateSuccess();
onAuthenticateFailed();
onAuthenticateError();
- manger.authenticate(cryptoObject, mCancellationSignal, 0, mAuthCallback, null);
这里的四个参数分别是:
- 第一个参数是一个加密对象。这里的 CryptoObject 对象就是使用 Cipher 对象创建创建出来的:new FingerprintManager.CryptoObject(cipher)。
- 第二个参数是一个 CancellationSignal 对象,该对象提供了取消操作的能力。创建该对象也很简单,使用 new CancellationSignal() 就可以了。
- 第三个参数是一个标志,默认为0。
- 第四个参数是 AuthenticationCallback 对象,它本身是 FingerprintManager 类里面的一个抽象类。该类提供了指纹识别的几个回调方法,包括指纹识别成功、失败等。需要我们重写。
- 最后一个 Handler,可以用于处理回调事件,可以传null。
直接贴代码,大家参考一下:
- import android.Manifest;
- import android.app.KeyguardManager;
- import android.content.Context;
- import android.content.Intent;
- import android.content.pm.PackageManager;
- import android.hardware.fingerprint.FingerprintManager;
- import android.os.Bundle;
- import android.os.CancellationSignal;
- import android.support.v4.app.ActivityCompat;
- import android.support.v4.app.FragmentActivity;
- import android.util.Log;
- import android.view.View;
- import android.widget.Button;
- import android.widget.Toast;
-
-
-
- public class MainActivity extends FragmentActivity {
- FingerprintManager manager;
- KeyguardManager mKeyManager;
- private final static int REQUEST_CODE_CONFIRM_DEVICE_CREDENTIALS = 0;
- private final static String TAG = "finger_log";
-
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- manager = (FingerprintManager) this.getSystemService(Context.FINGERPRINT_SERVICE);
- mKeyManager = (KeyguardManager) this.getSystemService(Context.KEYGUARD_SERVICE);
- Button btn_finger = (Button) findViewById(R.id.btn_activity_main_finger);
- btn_finger.setOnClickListener(new View.OnClickListener() {
- @Override
- public void onClick(View v) {
- if (isFinger()) {
- Toast.makeText(MainActivity.this, "请进行指纹识别", Toast.LENGTH_LONG).show();
- Log(TAG, "keyi");
- startListening(null);
- }
- }
- });
-
- }
-
- public boolean isFinger() {
-
- //android studio 上,没有这个会报错
- if (ActivityCompat.checkSelfPermission(this, Manifest.permission.USE_FINGERPRINT) != PackageManager.PERMISSION_GRANTED) {
- Toast.makeText(this, "没有指纹识别权限", Toast.LENGTH_SHORT).show();
- return false;
- }
- Log(TAG, "有指纹权限");
- //判断硬件是否支持指纹识别
- if (!manager.isHardwareDetected()) {
- Toast.makeText(this, "没有指纹识别模块", Toast.LENGTH_SHORT).show();
- return false;
- }
- Log(TAG, "有指纹模块");
- //判断 是否开启锁屏密码
-
- if (!mKeyManager.isKeyguardSecure()) {
- Toast.makeText(this, "没有开启锁屏密码", Toast.LENGTH_SHORT).show();
- return false;
- }
- Log(TAG, "已开启锁屏密码");
- //判断是否有指纹录入
- if (!manager.hasEnrolledFingerprints()) {
- Toast.makeText(this, "没有录入指纹", Toast.LENGTH_SHORT).show();
- return false;
- }
- Log(TAG, "已录入指纹");
-
- return true;
- }
-
- CancellationSignal mCancellationSignal = new CancellationSignal();
- //回调方法
- FingerprintManager.AuthenticationCallback mSelfCancelled = new FingerprintManager.AuthenticationCallback() {
- @Override
- public void onAuthenticationError(int errorCode, CharSequence errString) {
- //但多次指纹密码验证错误后,进入此方法;并且,不能短时间内调用指纹验证
- Toast.makeText(MainActivity.this, errString, Toast.LENGTH_SHORT).show();
- showAuthenticationScreen();
- }
-
- @Override
- public void onAuthenticationHelp(int helpCode, CharSequence helpString) {
-
- Toast.makeText(MainActivity.this, helpString, Toast.LENGTH_SHORT).show();
- }
-
- @Override
- public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
-
- Toast.makeText(MainActivity.this, "指纹识别成功", Toast.LENGTH_SHORT).show();
- }
-
- @Override
- public void onAuthenticationFailed() {
- Toast.makeText(MainActivity.this, "指纹识别失败", Toast.LENGTH_SHORT).show();
- }
- };
-
-
- public void startListening(FingerprintManager.CryptoObject cryptoObject) {
- //android studio 上,没有这个会报错
- if (ActivityCompat.checkSelfPermission(this, Manifest.permission.USE_FINGERPRINT) != PackageManager.PERMISSION_GRANTED) {
- Toast.makeText(this, "没有指纹识别权限", Toast.LENGTH_SHORT).show();
- return;
- }
- manager.authenticate(cryptoObject, mCancellationSignal, 0, mSelfCancelled, null);
-
-
- }
-
- /**
- * 锁屏密码
- */
- private void showAuthenticationScreen() {
-
- Intent intent = mKeyManager.createConfirmDeviceCredentialIntent("finger", "测试指纹识别");
- if (intent != null) {
- startActivityForResult(intent, REQUEST_CODE_CONFIRM_DEVICE_CREDENTIALS);
- }
- }
-
- @Override
- protected void onActivityResult(int requestCode, int resultCode, Intent data) {
- if (requestCode == REQUEST_CODE_CONFIRM_DEVICE_CREDENTIALS) {
- // Challenge completed, proceed with using cipher
- if (resultCode == RESULT_OK) {
- Toast.makeText(this, "识别成功", Toast.LENGTH_SHORT).show();
- } else {
- Toast.makeText(this, "识别失败", Toast.LENGTH_SHORT).show();
- }
- }
- }
-
- private void Log(String tag, String msg) {
- Log.d(tag, msg);
- }
- }
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