通过获取设备信息来自定义导航栏高度

App({
  onLaunch() {
    //用于获取设备的信息
    wx.getSystemInfo({
      success: res => {
        console.log(res)
        //安卓设定的导航栏高度为48px，iOS设定的导航栏高度为44px
        let navHeight = 44
        if (res.system.indexOf('iOS') !== -1) { //判断当前设备是 ios或android
          navHeight = 44
        } else {
          navHeight = 48
        }
        //设置导航高度
        this.globalData.navHeight = (res.statusBarHeight + navHeight) * (750 / res.windowWidth);
        this.globalData.contentHeight = (res.screenHeight - res.statusBarHeight - navHeight) * (750 /
          res.windowWidth);
          
          console.log(this.globalData.navHeight)
      }
    })
  },
  globalData: {
    navHeight:0
  }
})