萌新求问 >>> plus中不能访问vue里的data和方法 怎么解决

代码：

plus.runtime.openURL(this.latestVersionUrl + '?appId=' + this.appId + 'platform=' + this.platform, function(res) {  
                                    console.log(res);  
                                });

报错：
undefined is not an object (evaluating 'this.latestVersionUrl');at api *** success callback function