核心

Android 指纹 是在 6.0 才出来的一个重要的功能

@RequiresApi(api = Build.VERSION_CODES.M)

核心的两个 api:

FingerprintManager
KeyguardManager

step1

判断android 版本，如果小于 6.0 支持不了指纹

if(Build.VERSION.SDK_INT < Build.VERSION_CODES.M){
return;
}

step2

判断 手机硬件（有没有指纹感应区）就是手机是否支持传感

  @RequiresApi(api = Build.VERSION_CODES.M)
    public boolean isHardFinger() {
        if (fingerprintManager != null && fingerprintManager.isHardwareDetected()) {
            return true;
        } else {
            return false;
        }
    }

step3

检查手机是否开启锁屏密码（如手机未开锁，涉及到一个优先级问题，先解锁 后使用）

  public boolean isWindowSafe() {
        if (keyguardManager != null && keyguardManager.isKeyguardSecure()) {
            return true;
        } else {
            return false;
        }
    }

step4

检查手机是否有录入指纹

  @RequiresApi(api = Build.VERSION_CODES.M)
    public boolean isHaveHandler() {
        if (fingerprintManager != null && fingerprintManager.hasEnrolledFingerprints()) {
            return true;
        } else {
            return false;
        }
    }

只有以上步骤全满足，才能使用指纹

开启指纹验证

    @RequiresApi(api = Build.VERSION_CODES.M)
    public void authenticate(FingerprintManager.CryptoObject cryptoObject, CancellationSignal cancellationSignal,
                             int flag,
                             FingerprintManager.AuthenticationCallback authenticationCallback, Handler handler) {
        if (fingerprintManager != null) {
            fingerprintManager.authenticate(cryptoObject, cancellationSignal, flag, authenticationCallback, handler);
        }
    }

参数中最重要的就是 cancellationSignal和 callback，其他传null 和 0 就行，
cancellationsignal  是用来取消指纹验证的，而callback 可以回调 指纹验证失败次数 或者指纹验证成功、

最后附上简单工具类

public class FingerUtils {

    private final FingerprintManager fingerprintManager;
    private final KeyguardManager keyguardManager;

    @RequiresApi(api = Build.VERSION_CODES.M)
    private FingerUtils(Context context) {
        fingerprintManager = (FingerprintManager) context.getSystemService(Context.FINGERPRINT_SERVICE);
        keyguardManager = (KeyguardManager) context.getSystemService(Context.KEYGUARD_SERVICE);
    }

    private static FingerUtils singleton = null;

    @RequiresApi(api = Build.VERSION_CODES.M)
    public static FingerUtils getInstance(Context context) {
        if (singleton == null) {
            synchronized (FingerUtils.class) {
                if (singleton == null) {
                    singleton = new FingerUtils(context);
                }
            }
        }
        return singleton;
    }


    

    @RequiresApi(api = Build.VERSION_CODES.M)
    public boolean isHardFinger() {
        if (fingerprintManager != null && fingerprintManager.isHardwareDetected()) {
            return true;
        } else {
            return false;
        }
    }

    

    public boolean isWindowSafe() {
        if (keyguardManager != null && keyguardManager.isKeyguardSecure()) {
            return true;
        } else {
            return false;
        }
    }

    
    @RequiresApi(api = Build.VERSION_CODES.M)
    public boolean isHaveHandler() {
        if (fingerprintManager != null && fingerprintManager.hasEnrolledFingerprints()) {
            return true;
        } else {
            return false;
        }
    }

    
    @RequiresApi(api = Build.VERSION_CODES.M)
    public void authenticate(FingerprintManager.CryptoObject cryptoObject, CancellationSignal cancellationSignal,
                             int flag,
                             FingerprintManager.AuthenticationCallback authenticationCallback, Handler handler) {
        if (fingerprintManager != null) {
            fingerprintManager.authenticate(cryptoObject, cancellationSignal, flag, authenticationCallback, handler);
        }
    }

    
    public void cannelFinger(CancellationSignal cancellationSignal) {
        cancellationSignal.cancel();

    }
}

`