动态加载字体真机不行

Creator 2.x
#1

cc.loader.load({ url: ${wx.env.USER_DATA_PATH}"/font/MaShanZheng-Regular.ttf", type: “ttf” }, (err, font) => {

            if (!err) {

                let MaShanZheng = new cc.TTFFont()

                MaShanZheng.name = "Ma Shan Zheng"

                MaShanZheng["_nativeAsset"] = font

                // 重写cc.Label的_onLoad方法

                const originalOnLoad = cc.Label.prototype["onLoad"]

                cc.Label.prototype["onLoad"] = function () {

                    this.font = MaShanZheng

                    this._forceUpdateRenderData(true)

                    originalOnLoad.call(this) // 调用原始的_onLoad方法

                }

            }

        })