微信小程序自定义导航栏（模板化）

<template name="CustomNavBar">
 <block wx:if="{{ showNavBar }}">

 <!-- 自定义导航栏悬浮时，卡空行 -->
 <block wx:if="{{ needFixed }}">
  <view style="position: relative; width: 100%; height: {{ navHeight }}px;"></view>
 </block>

 <view class="custom-navbar-con relative {{ iOS ? ' ios ' : ' android ' }}" style="height: {{ navHeight }}px; {{ needFixed ? 'position: fixed; top: 0;' : '' }}">
  <view class="custom-navbar-statusbar-con relative" style="height: {{ statusBarHeight }}px;"></view>
  <view class="custom-navbar-content relative" style="height: {{ navHeight - statusBarHeight }}px;">

  <!-- iOS端的导航栏显示方式 -->
  <block wx:if="{{ navTitle && navTitle.length > 0 }}">
   <view class="custom-navbar-title ios">{{ navTitle }}</view>
  </block>

  <block wx:if="{{ showLeftMenu }}">
   <view class="custom-navbar-left-menu-con clearfix" style="top: {{ navRightMenuRect.top - statusBarHeight - 1 }}px; left: {{ winWidth - navRightMenuRect.right }}px; height: {{ navRightMenuRect.height + 2 }}px;">
   <block wx:if="{{ showBackBtn }}">
    <view class="custom-navbar-icon-btn pull-left back" style="height: {{ navRightMenuRect.height }}px" bindtap="customNavBarBack">
    <image class="icon" src="../../image/icon-nav-back.png" mode="aspectFit" style="width: {{ navRightMenuRect.height }}px;" />
    <text class="text"></text>
    </view>
   </block>

   <block wx:if="{{ showHomeBtn }}">
    <view class="custom-navbar-icon-btn pull-left home" style="height: {{ navRightMenuRect.height }}px" bindtap="customNavBarBackToHome">
    <image class="icon" src="../../image/icon-nav-home.png" mode="aspectFit" style="width: {{ navRightMenuRect.height }}px;" />
    <text class="text"></text>
    </view>
   </block>

   <!-- android端的导航栏显示方式 -->
   <block wx:if="{{ navTitle && navTitle.length > 0 }}">
    <view class="custom-navbar-title android pull-left" style="line-height: {{ navRightMenuRect.height - 2 }}px;">{{ navTitle }}</view>
   </block>
   </view>
  </block>
  </view>
 </view>
 </block>
</template>

.custom-navbar-con { position: relative; width: 100%; background-color: white; z-index: 9999; }
.custom-navbar-con .custom-navbar-statusbar-con { width: 100%; }
.custom-navbar-con .custom-navbar-content { width: 100%; }
.custom-navbar-con .custom-navbar-left-menu-con { position: absolute; }
.custom-navbar-con .custom-navbar-left-menu-con .custom-navbar-icon-btn { height: 100%; border-radius: 200px; border: 1px solid rgba(220, 220, 220, 0.6); }
.custom-navbar-con .custom-navbar-left-menu-con .custom-navbar-icon-btn .icon { height: 90%; margin-top: 2.5%; }
.custom-navbar-con .custom-navbar-left-menu-con .custom-navbar-icon-btn .text { font-size: 27rpx; }
.custom-navbar-con .custom-navbar-left-menu-con .custom-navbar-icon-btn.back { border: none; }
.custom-navbar-con .custom-navbar-left-menu-con .custom-navbar-icon-btn.back~.custom-navbar-icon-btn.home { margin-left: 10rpx; }
.custom-navbar-con .custom-navbar-left-menu-con .custom-navbar-icon-btn.switch-shop { padding-left: 5px; padding-right: 25rpx; }


.custom-navbar-con.ios .custom-navbar-title.android { display: none; }
.custom-navbar-con.android .custom-navbar-title.ios { display: none; }
.custom-navbar-con .custom-navbar-title.ios { font-weight: bold; text-align: center; position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); -webkit-transform: translate(-50%, -50%); }
.custom-navbar-con .custom-navbar-title.android { padding-left: 30rpx; }```

```javascript
module.exports = function(PageInstance) {
 let App = getApp()

 let _tplData = {
 _CustomNavBar_: {
  navRightMenuRect: App.NavRightMenuRect,
  navRightMenuCenterY: App.NavRightMenuCenterY,
  statusBarHeight: App.StatusBarHeight,
  winWidth: App.WinWidth,
  winHeight: App.WinHeight,
  iOS: App.iOS,

  navTitle: '', // 当前只合适短标题，如需长标题，建议隐藏自定义导航栏，自定义展示
  navHeight: App.CustomNavHeight,

  needFixed: false,

  showNavBar: !App.NavRightMenuRect ? false : true,
  showLeftMenu: true,
  showBackBtn: true,
  showHomeBtn: false
 }
 }

 let _tplMethods = {
 customNavBarBack() {
  wx.navigateBack()
 },
 customNavBarBackToHome() {
  let url = '/pages/index/index'
  wx.reLaunch({
  url: url
  })
 }
 }
 let isIndexPage = !!(PageInstance.route == 'pages/index/index')
 let pages = getCurrentPages()
 if (pages.length == 1) {
 _tplData._CustomNavBar_.showBackBtn = false
 _tplData._CustomNavBar_.showHomeBtn = !isIndexPage
 }

 // 每个页面 可单独配置自定义导航栏
 if (PageInstance.data.CustomNavBarConfig) {
 Object.assign(_tplData._CustomNavBar_, PageInstance.data.CustomNavBarConfig)
 }

 // !!!! 最后执行
 // 当无法获取到右上角按钮胶囊的布局位置时，强制设置自定义导航栏为隐藏状态
 if (!App.NavRightMenuRect) {
 _tplData._CustomNavBar_.showNavBar = false
 }

 Object.assign(PageInstance, _tplMethods)
 PageInstance.setData(_tplData)
 return this
}

// 自定义导航栏
import CustomNavBar from './template/CustomNavBar/CustomNavBar';

 App({
 //自定义 模板式 组件
 CustomNavBar,
 
 // 系统信息
  WinWidth: 0,
  WinHeight: 0,
  StatusBarHeight: 0,
  PixelRatio: 1,
  SystemFullName: '',
  SystemVersion: '',
  SystemSDKVersion: '',

  //自定义导航栏相关
  NavRightMenuRect: null,
  NavRightMenuCenterY: 0,
  CustomNavHeight: 0,
  
 onLaunch: function (options) {
 let self = this
 let systemInfo = wx.getSystemInfoSync()
 self.iOS = systemInfo.platform === 'ios'
 self.isDebug = systemInfo.platform === 'devtools'
 if (self.isDebug) {
  // 单纯为了在开发工具下调试 自定义导航栏
  // 开发工具下不存在App版本号的区分
  systemInfo.version = '7.0.0'
 }
 self.WinWidth = systemInfo.windowWidth
 self.WinHeight = systemInfo.windowHeight
 self.StatusBarHeight = systemInfo.statusBarHeight
 // 部分小程序库版本没有返回状态栏高度
 if (!self.StatusBarHeight) {
  self.StatusBarHeight = 20
 }
 self.PixelRatio = Math.max(systemInfo.pixelRatio, 2)
 self.SystemFullName = systemInfo.system
 self.SystemVersion = systemInfo.version
 self.SystemSDKVersion = systemInfo.SDKVersion

 // app.json全局配置的自定义导航栏的话，客户端需求版本为6.6.0
 // 每个页面 单独配置的自定义导航栏的话，客户端需求版本为7.0.0
 // wx.getMenuButtonBoundingClientRect方法，要求基础库版本为2.1.0
 if (self.compareVersion(self.SystemVersion, '6.6.0') >= 0) {
  // 官方的6.6.0版本以上客户端，最低基础库版本为1.9.4
  // 6.6.0以上且[1.9.4 - 2.1.0]范围内的机型无法使用wx.getMenuButtonBoundingClientRect
  // 所以手动写死非全面屏手机的适配胶囊布局位置
  self.NavRightMenuRect = {
  top: 26,
  bottom: 58,
  right: self.WinWidth - 10,
  width: 87,
  height: 32
  }
  // 如果系统信息返回的状态栏高度大于20，认为是全面屏手机
  if (self.StatusBarHeight > 20) {
  self.NavRightMenuRect.top = 50
  self.NavRightMenuRect.bottom = 82
  }

  // 2019年08月21日22:09:22
  // 微信小程序库出现bug，导致部分机型wx.getMenuButtonBoundingClientRect无返回值
  // 所以在这之前先默认写死一个NavRightMenuRect，防止全局的自定义导航栏已经隐藏了但是无法显示自定义导航栏
  // 详见https://developers.weixin.qq.com/community/develop/doc/00062238d78e880aedd88b72351c00
  if (wx.getMenuButtonBoundingClientRect) {
  let NavRightMenuRect = wx.getMenuButtonBoundingClientRect()
  self.NavRightMenuRect = {
   top: NavRightMenuRect.top,
   bottom: NavRightMenuRect.bottom,
   right: NavRightMenuRect.right,
   width: NavRightMenuRect.width,
   height: NavRightMenuRect.height
  }
  }

  self.NavRightMenuCenterY = self.NavRightMenuRect.top + self.NavRightMenuRect.height / 2
  self.CustomNavHeight = self.NavRightMenuRect.bottom + (self.NavRightMenuRect.top - self.StatusBarHeight)
 } else {
  self.NavRightMenuRect = null
  self.CustomNavHeight = 0
 }
 },
 
  // 比较两个版本号
 compareVersion (v1, v2) => {
   v1 = v1.split('.')
   v2 = v2.split('.')
   const len = Math.max(v1.length, v2.length)
 
   while (v1.length < len) {
     v1.push('0')
   }
   while (v2.length < len) {
     v2.push('0')
   }
 
   for (let i = 0; i < len; i++) {
     const num1 = parseInt(v1[i])
     const num2 = parseInt(v2[i])
 
     if (num1 > num2) {
       return 1
     } else if (num1 < num2) {
       return -1
     }
   }
   return 0
 } 
    
}),

<!-- 自定义NavBar -->
<import src="../../template/CustomNavBar/CustomNavBar.wxml" />
<template is="CustomNavBar" data="{{ ..._CustomNavBar_ }}"></template>

onLoad: function(options) {
  new App.CustomNavBar(this)
 }