boolean enabled = isNotificationEnabled(MainActivity.this);

    if (!enabled) {
      /**
       * 跳到通知欄設置界面
       * @param context
       */
        Intent localIntent = new Intent();
        //直接跳轉到應用通知設置的代碼：
        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
            localIntent.setAction("android.settings.APP_NOTIFICATION_SETTINGS");
            localIntent.putExtra("app_package", context.getPackageName());
            localIntent.putExtra("app_uid", context.getApplicationInfo().uid);
        } else if (android.os.Build.VERSION.SDK_INT == Build.VERSION_CODES.KITKAT) {
            localIntent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
            localIntent.addCategory(Intent.CATEGORY_DEFAULT);
            localIntent.setData(Uri.parse("package:" + context.getPackageName()));
        } else {
            //4.4以下沒有從app跳轉到應用通知設置頁面的Action，可考慮跳轉到應用詳情頁面,
            localIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            if (Build.VERSION.SDK_INT >= 9) {
                localIntent.setAction("android.settings.APPLICATION_DETAILS_SETTINGS");
                localIntent.setData(Uri.fromParts("package", context.getPackageName(), null));
            } else if (Build.VERSION.SDK_INT <= 8) {
                localIntent.setAction(Intent.ACTION_VIEW);
                localIntent.setClassName("com.android.settings", "com.android.setting.InstalledAppDetails");
                localIntent.putExtra("com.android.settings.ApplicationPkgName", context.getPackageName());
            }
        }
        context.startActivity(localIntent);
    }

     /**
       * 獲取通知權限
       * @param context
       */
    @TargetApi(Build.VERSION_CODES.KITKAT)
    private boolean isNotificationEnabled(Context context) {

        String CHECK_OP_NO_THROW = "checkOpNoThrow";
        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;
        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 = (Integer) opPostNotificationValue.get(Integer.class);
            return ((Integer) checkOpNoThrowMethod.invoke(mAppOps, value, uid, pkg) == AppOpsManager.MODE_ALLOWED);

        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }