指纹识别入门（1）

项目需要实现指纹登录。现弄一个能跑的案例：

开发工具：Android studio 

需要注意以下几点：

1 判断设备的API是否大于22，

2.是否有指纹识别模块，

3.判断设备是否设置了锁屏密码，

4.是否录入指纹

添加权限：

 

 

第二步：界面：

第三步：Activity

package com.cordovatest.shanghai.figuretest4;


import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;


import android.Manifest;
import android.annotation.TargetApi;
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.Build;
import android.os.CancellationSignal;
import android.support.v4.app.ActivityCompat;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;




@TargetApi(Build.VERSION_CODES.M)
public class MainActivity extends AppCompatActivity implements View.OnClickListener{


    private FingerprintManager manager;//访问指纹硬件的类
    private KeyguardManager keyManager;//管理锁屏的类
    private CancellationSignal signal = new CancellationSignal();
    //此类基于Java加密API的一个包装类,用于防止在指纹扫描中被第三方恶意攻击
    private FingerprintManager.CryptoObject cryptoObject;
    private static final int REQUST_CODE=1;
    private ImageView image;
    private String minSdkVersion;
    private  int i=0;
    private TextView start_tv;
    private TextView cancel_tv;






    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        image= (ImageView) findViewById(R.id.image);
        start_tv = (TextView) findViewById(R.id.start_tv);
        cancel_tv = (TextView) findViewById(R.id.cancel_tv);
        start_tv.setOnClickListener(this);
        cancel_tv.setOnClickListener(this);


        minSdkVersion= Build.VERSION.SDK;


    }


    private void initLowSDK() {
        Toast.makeText(getBaseContext(), "目前指纹识别只支持6.0以上的系统哦!", Toast.LENGTH_LONG).show();
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(requestCode==REQUST_CODE && resultCode==RESULT_OK){
            Toast.makeText(getBaseContext(), "识别成功!", Toast.LENGTH_SHORT).show();
            image.setImageResource(R.drawable.fingerprint_);
        }else{
            Toast.makeText(getBaseContext(), "识别失败!", Toast.LENGTH_SHORT).show();
        }
    }






    /**
     * 获得系统服务对象的引用
     */
    private void initFinger() {
        //通过V4包获得对象
        manager = (FingerprintManager) getSystemService(Context.FINGERPRINT_SERVICE);
        keyManager= (KeyguardManager) getSystemService(Context.KEYGUARD_SERVICE);


    }
    @TargetApi(Build.VERSION_CODES.M)
    private boolean isFingerprint(){
        //此方法为了保证判断是否支持支持指纹不报错
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.USE_FINGERPRINT) != PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(getBaseContext(), "没有指纹解锁的权限", Toast.LENGTH_SHORT).show();
            return false;
        }
        //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;
        }
        //判断是否有锁屏密码
        if(!keyManager.isKeyguardSecure()){
            Toast.makeText(getBaseContext(), "请设置锁屏密码", Toast.LENGTH_SHORT).show();
            return false;
        }
        //判断是否录入指纹
        if (!manager.hasEnrolledFingerprints()) {
            Toast.makeText(getBaseContext(), "没有录入指纹", Toast.LENGTH_SHORT).show();
            return false;
        }
        return true;
    }


    /**
     * 开始指纹识别
     */
    private void startListen() {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.USE_FINGERPRINT) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        FingerprintManager.AuthenticationCallback callBack=new FingerprintManager.AuthenticationCallback() {
            @Override
            public void onAuthenticationError(int errorCode, CharSequence errString) {
                super.onAuthenticationError(errorCode, errString);
                Toast.makeText(getBaseContext(), "操作过于频繁,请稍后再试",Toast.LENGTH_SHORT).show();
            }


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


            //指纹识别成功
            @Override
            public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {
                super.onAuthenticationSucceeded(result);
                Toast.makeText(getBaseContext(), "指纹识别成功",Toast.LENGTH_SHORT).show();
                image.setImageResource(R.drawable.fingerprint_);
            }


            //指纹识别失败
            @Override
            public void onAuthenticationFailed() {
                super.onAuthenticationFailed();
                Toast.makeText(getBaseContext(), "指纹识别失败", Toast.LENGTH_SHORT).show();
                i++;
                if(i==3){
                    Toast.makeText(getBaseContext(), "失败次数过多,请输入锁屏密码", Toast.LENGTH_SHORT).show();
                    showLockScreenPass();
                    i=0;
                }
            }
        };
        manager.authenticate(cryptoObject, signal, 0, callBack, null);


    }
    //取消指纹识别
    public void stopListening() {
        if (signal != null) {
           // selfCancelled = true;
            signal.cancel();
            signal = null;
            Toast.makeText(getBaseContext(), "您已经取消指纹识别", Toast.LENGTH_SHORT).show();
        }
    }


    /**
     *指纹识别错误次数过多,显示手机锁屏密码
     */
    private void showLockScreenPass() {
        Intent intent=keyManager.createConfirmDeviceCredentialIntent("finger","开启锁屏密码");
        if(intent!=null){
            startActivityForResult(intent, REQUST_CODE);
        }
    }


    @Override
    public void onClick(View view) {
        int id = view.getId();
        switch (id){
            case R.id.start_tv:
                if(Double.parseDouble(minSdkVersion)>=23) {
                    initFinger();
                    if (isFingerprint()) {
                        startListen();
                    }
                }else{
                    initLowSDK();
                }
                break;
            case R.id.cancel_tv:
                stopListening();
                break;
            default:
                break;




        }
    }
}



参考：http://blog.csdn.net/huiling815/article/details/52469483