微信小程序全局开启分享朋友或者朋友圈

//1.在app.js定义方法
overShare: function () {
    wx.onAppRoute(function (res) { 
       let pages = getCurrentPages(), 
       view = pages[pages.length - 1]
       if (view) { 
            wx.showShareMenu({ withShareTicket: true,
            menus: ['shareAppMessage', 'shareTimeline'] 
            }) 
       } 
   }) 
},
//2.在onLaunch钩子中调用方法
onLaunch: function () { 　　
    this.overShare() 
}