微信小程序（18）-- 自定义头部导航栏

最近做的项目涉及相应的页面显示相应的顶部标题，所以就需要自定义头部导航了。

首先新建一个顶部导航公用组件topnav，导航高度怎么计算？

1.wx.getSystemInfo 和 wx.getSystemInfoSync 获取机器信息
2.screenHeight - windowHeight 计算标题栏高度
3.标题栏高度
'iPhone': 64,
'iPhone X': 88,
'android': 68

app.js

//app.js
App({
  onLaunch: function () {
    var that = this
    wx.getSystemInfo({
      success: function (res) {
        that.globalData.platform = res.platform
        let totalTopHeight = 68
        if (res.model.indexOf('iPhone X') !== -1) {
          totalTopHeight = 88
        } else if (res.model.indexOf('iPhone') !== -1) {
          totalTopHeight = 64
        }
        that.globalData.statusBarHeight = res.statusBarHeight
        that.globalData.titleBarHeight = totalTopHeight - res.statusBarHeight
      },
      failure() {
        that.globalData.statusBarHeight = 0
        that.globalData.titleBarHeight = 0
      }
    })
 })

还需更改配置app.json

"window": {
    "backgroundTextStyle": "light",
    "navigationBarBackgroundColor": "#15ae67",
    "navigationBarTitleText": "微信小程序",
    "navigationBarTextStyle": "white",
    "navigationStyle": "custom"
   //自定义导航栏配置
  }

topnav.wxml

<!--template.wxml-->
<!-- 这是自定义组件的内部WXML结构 -->
<view style="padding-top:{{someData.statusBarHeight+someData.titleBarHeight}}px">
  <view class="hh-header">
    <view class="status-bar" style="height:{{someData.statusBarHeight}}px"></view>
    <view class="title-bar" style="height:{{someData.titleBarHeight}}px">
      <view wx:if="{{isShowBack=='true'}}" class='hh-nav-back ico-back' bindtap='goback'></view>
      <view wx:if="{{isShowBack=='false'}}" class='hh-nav-back'></view>
      <view class="hh-title">{{innerTitle}}</view>
      <view class="hh-nav-right"></view>
    </view>
  </view>
</view>
<slot></slot>

topnav.json

{
  "component": true
}

topnav.js

const app = getApp()
Component({
  properties: {
    // 这里定义了innerText属性，属性值可以在组件使用时指定
    innerTitle: {
      type: String,
      value: '头部标题'
    },
    isShowBack: {
      type: String,
      value: "true"
    }
  },
  data: {
    // 这里是一些组件内部数据
    someData: {
      statusBarHeight: app.globalData.statusBarHeight,
      titleBarHeight: app.globalData.titleBarHeight
    }
  },
  methods: {
    // 这里是一个自定义方法
    goback: function () {
      wx.navigateBack({
        delta: 1,
      })
     }
  }
})

topnav.wxss

.ico-back{
   36rpx;
  height: 36rpx;
  background-size: contain;
  background-image: url(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACQAAAAkCAYAAADhAJiYAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAAAyZpVFh0WE1MOmNvbS5hZG9iZS54bXAAAAAAADw/eHBhY2tldCBiZWdpbj0i77u/IiBpZD0iVzVNME1wQ2VoaUh6cmVTek5UY3prYzlkIj8+IDx4OnhtcG1ldGEgeG1sbnM6eD0iYWRvYmU6bnM6bWV0YS8iIHg6eG1wdGs9IkFkb2JlIFhNUCBDb3JlIDUuNi1jMDY3IDc5LjE1Nzc0NywgMjAxNS8wMy8zMC0yMzo0MDo0MiAgICAgICAgIj4gPHJkZjpSREYgeG1sbnM6cmRmPSJodHRwOi8vd3d3LnczLm9yZy8xOTk5LzAyLzIyLXJkZi1zeW50YXgtbnMjIj4gPHJkZjpEZXNjcmlwdGlvbiByZGY6YWJvdXQ9IiIgeG1sbnM6eG1wPSJodHRwOi8vbnMuYWRvYmUuY29tL3hhcC8xLjAvIiB4bWxuczp4bXBNTT0iaHR0cDovL25zLmFkb2JlLmNvbS94YXAvMS4wL21tLyIgeG1sbnM6c3RSZWY9Imh0dHA6Ly9ucy5hZG9iZS5jb20veGFwLzEuMC9zVHlwZS9SZXNvdXJjZVJlZiMiIHhtcDpDcmVhdG9yVG9vbD0iQWRvYmUgUGhvdG9zaG9wIENDIDIwMTUgKFdpbmRvd3MpIiB4bXBNTTpJbnN0YW5jZUlEPSJ4bXAuaWlkOjAwRjFBMThDOEU1NDExRThCQUMxRTFBRUNDRDNCMkJEIiB4bXBNTTpEb2N1bWVudElEPSJ4bXAuZGlkOjAwRjFBMThEOEU1NDExRThCQUMxRTFBRUNDRDNCMkJEIj4gPHhtcE1NOkRlcml2ZWRGcm9tIHN0UmVmOmluc3RhbmNlSUQ9InhtcC5paWQ6MDBGMUExOEE4RTU0MTFFOEJBQzFFMUFFQ0NEM0IyQkQiIHN0UmVmOmRvY3VtZW50SUQ9InhtcC5kaWQ6MDBGMUExOEI4RTU0MTFFOEJBQzFFMUFFQ0NEM0IyQkQiLz4gPC9yZGY6RGVzY3JpcHRpb24+IDwvcmRmOlJERj4gPC94OnhtcG1ldGE+IDw/eHBhY2tldCBlbmQ9InIiPz7a0EjNAAAA80lEQVR42sTYOw7DIAwGYNxuPXHnTtygvUAuWalyE6WRMlBj7N/GEkOiCD4B4eHCzEUq3ljruPMe9fcstxcJOmGOqNNADcwR+SABs6SDOphrKqiHSZ3UGkwaSItJAY1gwkGjmFCQBRMGsmJCQB4MHOTFQEEIDAyEwkBASIwGRIrFr/XBZy03InpbQFJcFHW8Gu+2nnmUiFAM2daLzz/DVtHtaSc1DIX87SEo9MLoRkVsHS5U1OZqRkUeP0yo6APaMCrjCDuEyjrkq1GZ1yAVKvui2EXNuEqLqFnJBgk1LR3TQi08OWF1RqmyH8SAtB0yvgIMAGA41d9Fo4AZAAAAAElFTkSuQmCC);
  background-repeat: no-repeat;
  background-position-x: 20rpx;
}
.hh-header {
  position: fixed;
  top: 0;
   100%;
  background-color: #14ae66;
  z-index: 99;
}
.hh-title{
  font-size: 38rpx;
  text-align: center;
  color: #fff;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.title-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.hh-nav-right{
   116px;
}
.hh-nav-back{
   116px;

}

这样组件就写好了  只需要在你每个页面里面用这个组件传不同的值就可以了。

index.wxml

<component-topnav inner-title="{{title}}"></component-topnav>  //显示返回按钮

 <component-topnav inner-title="我的管理" is-show-back="false"></component-topnav>  //不显示返回按钮

index.js

//获取应用实例
const app = getApp()
Page({
  data: {
    motto: 'Hello World',
    userInfo: {},
    title:'自定义导航标题'
  },
})

index.json

{
  "usingComponents": {
    "component-topnav": "/pages/component/topnav"
  }
}