app.js

App({
  globalData: {
   
  },
  onLaunch: function () {
    let menuButtonObject = wx.getMenuButtonBoundingClientRect();
    wx.getSystemInfo({
      success: res => {
        
        //导航高度
        let statusBarHeight = res.statusBarHeight,
          navTop = menuButtonObject.top,
          navHeight = statusBarHeight + menuButtonObject.height + (menuButtonObject.top - statusBarHeight)*2;
        this.globalData.navHeight = navHeight;
        this.globalData.navTop = navTop;
        this.globalData.windowHeight = res.windowHeight;
      },
      fail(err) {
        console.log(err);
      }
    })
  }
})