安卓 java。API<20的lang.VerifyError

Question

我制作了一个支持指纹安全的应用程序。只要我在API大于API 19的API上运行，所有这些都可以正常工作。当然，自从棉花糖以来，指纹只在设备中受支持，所以我用
介绍了与指纹有关的所有内容 如果（Build.VERSION.SDK_INT>；=Build.VERSION_CODES.M）{}
我得到了以下错误：

 java.lang.VerifyError: com/myapp/newapp/Introduction
    at java.lang.Class.newInstanceImpl(Native Method)
    at java.lang.Class.newInstance(Class.java:1208)
    at 安卓.app.Instrumentation.newActivity(Instrumentation.java:1061)
    at        安卓.app.ActivityThread.performLaunchActivity(ActivityThread.java:2112)
    at 安卓.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
    at 安卓.app.ActivityThread.access$800(ActivityThread.java:135)
    at 安卓.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
    at 安卓.os.Handler.dispatchMessage(Handler.java:102)
    at 安卓.os.Looper.loop(Looper.java:136)
    at 安卓.app.ActivityThread.main(ActivityThread.java:5017)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.安卓.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
    at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    at dalvik.system.NativeStart.main(Native Method)

我随信附上了这部分代码：

try {                                                               
            keyStore.load(null);
            SecretKey key = (SecretKey) keyStore.getKey(KEY_NAME,
                    null);
            cipher.init(Cipher.ENCRYPT_MODE, key);
            //Return true if the cipher has been initialized successfully//
            return true;
        } catch (KeyPermanentlyInvalidatedException e) {

            //Return false if cipher initialization failed//
            return false;
        } catch (KeyStoreException | CertificateException
                | UnrecoverableKeyException | IOException
                | NoSuchAlgorithmException | InvalidKeyException e) {
            throw new RuntimeException("Failed to init Cipher", e);
        }                                                                  

我不知道怎么解决它