自定义小程序导航栏，获取导航栏高度

?

1 2 3 4 5 6 7 8 9

let stateHeight = ""; //任务栏高度 wx.getSystemInfoAsync({   success: (result) => {     stateHeight = result.statusBarHeight; //状态栏高度     let sum = "";     sum = stateHeight + height + (top - stateHeight) * 2;     this.height = sum;   }, });