效果演示：
前提条件：
去阿里云矢量图标，下载8个图标，四个黑，四个红，如图：
新建文件夹icons，把图标放到该文件夹，然后把该文件夹移动到该项目的文件夹里面。如图所示
app.json
{
"pages": [
"pages/home/home",
"pages/category/category",
"pages/cart/cart",
"pages/my/my"
],
"window": {
"backgroundTextStyle": "light",
"navigationBarBackgroundColor": "#09bb07",
"navigationBarTitleText": "我的商场",
"navigationBarTextStyle": "white"
},
"tabBar": {
"color": "#999",
"selectedColor": "##09bb07",
"backgroundColor": "#fafafa",
"list": [
{
"pagePath": "pages/home/home",
"text": "首页",
"iconPath": "icons/_home.png",
"selectedIconPath": "icons/home.png"
},
{
"pagePath": "pages/category/category",
"text": "分类",
"iconPath": "icons/_category.png",
"selectedIconPath": "icons/category.png"
},
{
"pagePath": "pages/cart/cart",
"text": "购物车",
"iconPath": "icons/_cart.png",
"selectedIconPath": "icons/cart.png"
},
{
"pagePath": "pages/my/my",
"text": "我的",
"iconPath": "icons/_my.png",
"selectedIconPath": "icons/my.png"
}
]
},
"lazyCodeLoading": "requiredComponents",
"sitemapLocation": "sitemap.json"
}