检测Android应用的通知栏权限有没有开启（已经适配8.0以上系统）

public static boolean areNotificationsEnabled(Context context) {
    NotificationManagerCompat.from(context).areNotificationsEnabled();
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
        return true;
    }
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O){
        return isEnableV19(context);
    }else {
        return isEnableV26(context);
    }
}


private static boolean isEnableV19(Context context) {
    final String CHECK_OP_NO_THROW = "checkOpNoThrow";
    final String OP_POST_NOTIFICATION = "OP_POST_NOTIFICATION";
    AppOpsManager mAppOps = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
    ApplicationInfo appInfo = context.getApplicationInfo();
    String pkg = context.getApplicationContext().getPackageName();
    int uid = appInfo.uid;
    Class appOpsClass = null; /* Context.APP_OPS_MANAGER */
    try {
        appOpsClass = Class.forName(AppOpsManager.class.getName());
        Method checkOpNoThrowMethod = appOpsClass.getMethod(CHECK_OP_NO_THROW, Integer.TYPE, Integer.TYPE, String.class);
        Field opPostNotificationValue = appOpsClass.getDeclaredField(OP_POST_NOTIFICATION);
        int value = (int) opPostNotificationValue.get(Integer.class);
        return ((int) checkOpNoThrowMethod.invoke(mAppOps, value, uid, pkg) == AppOpsManager.MODE_ALLOWED);
    } catch (ClassNotFoundException e) {
    } catch (NoSuchMethodException e) {
    } catch (NoSuchFieldException e) {
    } catch (InvocationTargetException e) {
    } catch (IllegalAccessException e) {
    } catch (Exception e) {
    }
    return false;
}


private static boolean isEnableV26(Context context) {
    ApplicationInfo appInfo = context.getApplicationInfo();
    String pkg = context.getApplicationContext().getPackageName();
    int uid = appInfo.uid;
    try {
        NotificationManager notificationManager = (NotificationManager)
                context.getSystemService(Context.NOTIFICATION_SERVICE);
        Method sServiceField = notificationManager.getClass().getDeclaredMethod("getService");
        sServiceField.setAccessible(true);
        Object sService = sServiceField.invoke(notificationManager);

        Method method = sService.getClass().getDeclaredMethod("areNotificationsEnabledForPackage"
                , String.class, Integer.TYPE);
        method.setAccessible(true);
        return (boolean) method.invoke(sService, pkg, uid);
    } catch (Exception e) {
        return true;
    }
}