在百度上搜索了很久的关于微信小程序自定义tabbar组件如何实现，几乎没有一个比较全面的解答，故此将整体的流程记录下来。

1、首先按照官方组件在app.json中定义tabbar

tabbar组件官网doc

app.json中配置如下：

"tabBar": {
    "custom": true,
    "backgroundColor": "#FFFFFF",
    "borderStyle": "white",
    "list": [
      {
        "pagePath": "pages/index/index",
        "text": "首页",
        "iconPath": "./images/home.png",
        "selectedIconPath": "./images/home.png"
      },
      {
        "pagePath": "pages/me/me",
        "text": "个人中心",
        "iconPath": "./images/me.png",
        "selectedIconPath": "./images/me.png"
      }
    ]
  },
"usingComponents": {}

2、在项目根目录创建自定义tabbar组件，划重点：根目录，请看下图，不放根目录会导致this.getTabBar = null

image.png

参考官方文档

组件的名称也和官方文档保持一致，不要自定义

3、组件内容如下：

• custom-tab-bar/index.js

Component({
  data: {
    selected: 0,
    color: "#7A7E83",
    selectedColor: "#3cc51f",
    list: [{
      pagePath: "../../pages/index/index",
      iconPath: "../images/home.png",
      selectedIconPath: "../images/home.png",
      text: "首页"
    }, {
      pagePath: "../../pages/me/me",
      iconPath: "../images/me.png",
      selectedIconPath: "../images/me.png",
      text: "个人中心"
    }]
  },
  attached() {
  },
  methods: {
    switchTab(e) {
      const data = e.currentTarget.dataset
      const url = data.path
      wx.switchTab({url})
      this.setData({
        selected: data.index
      })
    }
  }
})

• custom-tab-bar/index.json

{
  "component": true
}

• custom-tab-bar/index.wxml

<cover-view class="tab-bar">
  <cover-view class="tab-bar-border"></cover-view>
  <cover-view wx:for="{{list}}" wx:key="index" class="tab-bar-item" data-path="{{item.pagePath}}" data-index="{{index}}" bindtap="switchTab">
    <cover-image src="{{selected === index ? item.selectedIconPath : item.iconPath}}"></cover-image>
    <cover-view style="color: {{selected === index ? selectedColor : color}}">{{item.text}}</cover-view>
  </cover-view>
</cover-view>

• custom-tab-bar/index.wxss

.tab-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 48px;
  background: white;
  display: flex;
  padding-bottom: env(safe-area-inset-bottom);
}

.tab-bar-border {
  background-color: rgba(0, 0, 0, 0.33);
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 1px;
  transform: scaleY(0.5);
}

.tab-bar-item {
  flex: 1;
  text-align: center;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
}

.tab-bar-item cover-image {
  width: 27px;
  height: 27px;
}

.tab-bar-item cover-view {
  font-size: 10px;
}

4、在pages下的各个页面组件引入tabbar，以首页举例：

• pages/index.json

{
  "usingComponents": {
    "custom-tab-bar": "../../custom-tab-bar/index"
  }
}

• pages/index.js

Page({
  onShow: function () {
    if (typeof this.getTabBar === 'function' && this.getTabBar()) {
      this.getTabBar().setData({
        selected: 0
      })
    }
  }
})

• pages/index.wxml

<view class="container">
  <custom-tab-bar></custom-tab-bar>
</view>

原文：http://wsfss.top/thread/2