//page A
const app = getApp() //獲取App.js實例
onShow() {//生命周期函數(shù)--監(jiān)聽頁面顯示
  if (app.globalData.backData) {
    this.setData({ //將B頁面更新完的值渲染到頁面上
      backData: app.globalData.backData
    },()=>{
     	delete app.globalData.backData //刪除數(shù)據(jù) 避免onShow重復(fù)渲染
    })
  }
}
//page B
const app = getApp() //獲取App.js實例
changeBackData(){
   app.globalData.backData = '我被修改了'
   wx.navigateBack()
}

//page A
  onShow: function () {
    let backData = wx.getStorageSync('backData')
    if(backData){
       this.setData({
     		 backData
    	},()=>{
     		 wx.removeStorageSync('backData')
    	})
    }
  },
 //page B
 changeBackData(){
    wx.setStorageSync('backData', '我被修改了')
    wx.navigateBack()
 },

//page B
changeBackData(){
    const pages = getCurrentPages();
    const beforePage = pages[pages.length - 2]
    beforePage.setData({  //會直接更新A頁面的數(shù)據(jù)，A頁面不需要其他操作
      backData: "我被修改了"
    })
}

//page A
 goPageB() {
    wx.navigateTo({
      url: 'B',
      events: {
        getBackData: res => { //在events里面添加監(jiān)聽事件
          this.setData({
            backData: res.backData
          })
        },
      },
    })
  },
//page B	
changeBackData(){
    const eventChannel = this.getOpenerEventChannel()
       eventChannel.emit('getBackData', {  
     	 backData: '我被修改了'
    });
     wx.navigateBack()
 }