小程序底部导航按钮实现

商城小程序需要四个底部导航按钮，遂记录一下实现过程

最终实现效果如下所示

新建一个小程序项目，我是创建了JS模板，项目创建完成后需要新建五个文件夹，其中四个（page子文件夹）用于存放pages文件，一个sources文件夹（与pages同级）用于存放资源文件，如图标文件

图标需要8个，因为选中的图标和未选中的图标需要进行区分

图标文件源于阿里巴巴矢量图库

需要在app.json中添加以下配置信息，其中tabBar是新增的，其余均为系统默认生成

{
  "pages": [
    "pages/Homepage/Homepage",
    "pages/index/index",
    "pages/logs/logs",
    "pages/Mine/mine",
    "pages/Recommend/recommend",
    "pages/ShoppingCart/shoppingCart"
  ],
  "tabBar": {
    "color": "#A9A9A9",
    "selectedColor": "#000000",
    "backgroundColor": "#FFFFFF",
    "borderStyle": "black",
    "position": "bottom",
    "custom": false,
    "list": [
      {
        "pagePath": "pages/Homepage/Homepage",
        "text": "首页",
        "iconPath": "source/img/main.png",
        "selectedIconPath": "source/img/main_selected.png"
      },
      {
        "pagePath": "pages/Recommend/recommend",
        "text": "推荐",
        "iconPath": "source/img/star.png",
        "selectedIconPath": "source/img/star_selected.png"
      },
      {
        "pagePath": "pages/ShoppingCart/shoppingCart",
        "text": "购物车",
        "iconPath": "source/img/shop.png",
        "selectedIconPath": "source/img/shop_selected.png"
      },
      {
        "pagePath": "pages/Mine/mine",
        "text": "个人中心",
        "iconPath": "source/img/my.png",
        "selectedIconPath": "source/img/my_selected.png"
      }
    ]
  },
  "window": {
    "navigationBarTextStyle": "black",
    "navigationBarTitleText": "Weixin",
    "navigationBarBackgroundColor": "#ffffff"
  },
  "style": "v2",
  "componentFramework": "glass-easel",
  "sitemapLocation": "sitemap.json",
  "lazyCodeLoading": "requiredComponents"
}