微信小程序组件通讯方式

2021年8月19日作者张舫

前言

数据通信在开发中是必不可少的一个环节，也是我们必须掌握的知识。知道得越多的数据通信方式，实现业务会更加得心应手。

下面我将这些通信方式归类介绍：

组件通信
全局通信
页面通信

组件通信

properties

父组件向子组件通信，与 Vue 的 props 作用相同。

父组件向子组件传数据：

<span class="hljs-tag"><<span class="hljs-name">my-component</span> <span class="hljs-attr">list</span>=<span class="hljs-string">"{{list}}"</span>></span><span class="hljs-tag"></<span class="hljs-name">my-component</span>></span>

1 2	<span class="hljs-tag"><<span class="hljs-name">my-component</span> <span class="hljs-attr">list</span>=<span class="hljs-string">"{{list}}"</span>></span><span class="hljs-tag"></<span class="hljs-name">my-component</span>></span>

子组件接收数据：

Component({
  <span class="hljs-attr">properties</span>:{
    <span class="hljs-attr">list</span>:{
      <span class="hljs-attr">type</span>: <span class="hljs-built_in">Array</span>,
      <span class="hljs-attr">value</span>: []
    }
  },
  <span class="hljs-function"><span class="hljs-title">attached</span>()</span>{
    <span class="hljs-built_in">console</span>.log(<span class="hljs-built_in">this.data</span>.list)
  }
})

Component({

properties:{

list:{

type: Array,

value: []

}

attached(){

console.log(this.data.list)

}

})

triggerEvent

子组件向父组件通信，与 Vue 的 $emit 作用相同

子组件触发自定义事件：

Component({
  <span class="hljs-function"><span class="hljs-title">attached</span>()</span>{
    <span class="hljs-built_in">this</span>.triggerEvent(<span class="hljs-string">'customEvent'</span>,{ <span class="hljs-attr">id</span>: <span class="hljs-number">10</span> })
  }
})

Component({

attached(){

this.triggerEvent('customEvent',{ id: 10 })

}

})

父组件接收自定事件：

<span class="hljs-tag"><<span class="hljs-name">my-component</span> <span class="hljs-attr">list</span>=<span class="hljs-string">"{{list}}"</span> <span class="hljs-attr">bind:customEvent</span>=<span class="hljs-string">"customEvent"</span>></span><span class="hljs-tag"></<span class="hljs-name">my-component</span>></span>

<my-component list="{{list}}" bind:customEvent="customEvent"></my-component>

Page({
  <span class="hljs-function"><span class="hljs-title">customEvent</span>(<span class="hljs-params">e</span>)</span>{
    <span class="hljs-built_in">console</span>.log(e.detail.id)
  }
})

Page({

customEvent(e){

console.log(e.detail.id)

}

})

selectComponent

使用选择器选择组件实例节点，返回匹配到的第一个组件实例对象，类似 Vue 的 ref

<span class="hljs-tag"><<span class="hljs-name">my-component</span> <span class="hljs-attr">id</span>=<span class="hljs-string">"mycomponent"</span> <span class="hljs-attr">list</span>=<span class="hljs-string">"{{list}}"</span>></span><span class="hljs-tag"></<span class="hljs-name">my-component</span>></span>

<my-component id="mycomponent" list="{{list}}"></my-component>

Page({
  <span class="hljs-function"><span class="hljs-title">onLoad</span>()</span>{
    <span class="hljs-keyword">let</span> mycomponent = <span class="hljs-built_in">this</span>.selectComponent(<span class="hljs-string">'#mycomponent'</span>)
    mycomponent.setData({
      <span class="hljs-attr">list</span>: []
    })
  }
})

Page({

onLoad(){

let mycomponent = this.selectComponent('#mycomponent')

mycomponent.setData({

list: []

})

}

})

selectOwnerComponent

选取当前组件节点所在的组件实例（即组件的引用者），返回它的组件实例对象，类似 Vue 的 $parent

Component({
  <span class="hljs-function"><span class="hljs-title">attached</span>()</span>{
    <span class="hljs-keyword">let</span> parent = <span class="hljs-built_in">this</span>.selectOwnerComponent()
    <span class="hljs-built_in">console</span>.log(parent)
  }
})

Component({

attached(){

let parent = this.selectOwnerComponent()

console.log(parent)

}

})

全局通信

globalData

将数据挂载到 app.js，这种方式在开发中很常用。通过getApp()，我们能够在任何一个页面内访问到app实例。

app.js

App({
  <span class="hljs-attr">globalData</span>:{
    <span class="hljs-attr">list</span>:[]
  }
})

App({

globalData:{

list:[]

}

})

page1.js

<span class="hljs-keyword">const</span> app = getApp()
Page({
  <span class="hljs-function"><span class="hljs-title">onLoad</span>()</span>{
    app.globalData.list.push({
      <span class="hljs-attr">id</span>: <span class="hljs-number">10</span>
    })
  }
})

const app = getApp()

Page({

onLoad(){

app.globalData.list.push({

id: 10

})

}

})

page2.js

<span class="hljs-keyword">const</span> app = getApp()
Page({
  <span class="hljs-function"><span class="hljs-title">onLoad</span>()</span>{
    <span class="hljs-built_in">console</span>.log(app.globalData.list) <span class="hljs-comment">// [{id:10}]</span>
  }
})

const app = getApp()

Page({

onLoad(){

console.log(app.globalData.list) // [{id:10}]

}

})

storage

storage并不是作为通信的主要方式。storage 主要是为了缓存数据，并且最多只能存储10M的数据，我们应该合理使用storage

wx.setStorageSync(<span class="hljs-string">'timestamp'</span>, <span class="hljs-built_in">Date</span>.now())
wx.getStorageSync(<span class="hljs-string">'timestamp'</span>)
wx.removeStorageSync(<span class="hljs-string">'timestamp'</span>)

wx.setStorageSync('timestamp', Date.now())

wx.getStorageSync('timestamp')

wx.removeStorageSync('timestamp')

eventBus

通过发布订阅模式注册事件和触发事件进行通信

简单实现

<span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">EventBus</span></span>{
  <span class="hljs-function"><span class="hljs-title">constructor</span>()</span>{
    <span class="hljs-built_in">this</span>.task = {}
  }

  <span class="hljs-function"><span class="hljs-title">on</span>(<span class="hljs-params">name, cb</span>)</span>{
    <span class="hljs-function"><span class="hljs-title">if</span>(<span class="hljs-params">!<span class="hljs-built_in">this</span>.task[name]</span>)</span>{
      <span class="hljs-built_in">this</span>.task[name] = []
    }
    <span class="hljs-keyword">typeof</span> cb === <span class="hljs-string">'function'</span> && <span class="hljs-built_in">this</span>.task[name].push(cb)
  }

  <span class="hljs-function"><span class="hljs-title">emit</span>(<span class="hljs-params">name, ...arg</span>)</span>{
    <span class="hljs-keyword">let</span> taskQueen = <span class="hljs-built_in">this</span>.task[name]
    <span class="hljs-function"><span class="hljs-title">if</span>(<span class="hljs-params">taskQueen && taskQueen.length > <span class="hljs-number">0</span></span>)</span>{
      taskQueen.forEach(<span class="hljs-function"><span class="hljs-params">cb</span>=></span>{
        cb(...arg)
      })
    }
  }

  <span class="hljs-function"><span class="hljs-title">off</span>(<span class="hljs-params">name, cb</span>)</span>{
    <span class="hljs-keyword">let</span> taskQueen = <span class="hljs-built_in">this</span>.task[name]
    <span class="hljs-function"><span class="hljs-title">if</span>(<span class="hljs-params">taskQueen && taskQueen.length > <span class="hljs-number">0</span></span>)</span>{
      <span class="hljs-keyword">let</span> index = taskQueen.indexOf(cb)
      index != -<span class="hljs-number">1</span> && taskQueen.splice(index, <span class="hljs-number">1</span>)
    }
  }

  <span class="hljs-function"><span class="hljs-title">once</span>(<span class="hljs-params">name, cb</span>)</span>{
    <span class="hljs-function"><span class="hljs-keyword">function</span> <span class="hljs-title">callback</span>(<span class="hljs-params">...arg</span>)</span>{
      <span class="hljs-built_in">this</span>.off(name, cb)
      cb(...arg)
    }
    <span class="hljs-keyword">typeof</span> cb === <span class="hljs-string">'function'</span> && <span class="hljs-built_in">this</span>.on(name, callback)
  }
}

<span class="hljs-keyword">export</span> <span class="hljs-keyword">default</span> EventBus

class EventBus{

constructor(){

this.task = {}

}

on(name, cb){

if(!this.task[name]){

this.task[name] = []

}

typeof cb === 'function' && this.task[name].push(cb)

}

emit(name, ...arg){

let taskQueen = this.task[name]

if(taskQueen && taskQueen.length > 0){

taskQueen.forEach(cb=>{

cb(...arg)

})

}

off(name, cb){

let taskQueen = this.task[name]

if(taskQueen && taskQueen.length > 0){

let index = taskQueen.indexOf(cb)

index != -1 && taskQueen.splice(index, 1)

}

once(name, cb){

function callback(...arg){

this.off(name, cb)

cb(...arg)

}

typeof cb === 'function' && this.on(name, callback)

}

export default EventBus

使用

app.js

<span class="hljs-keyword">import</span> EventBus <span class="hljs-keyword">from</span> <span class="hljs-string">'/util/EventBus'</span>

wx.$bus = <span class="hljs-keyword">new</span> EventBus()

import EventBus from '/util/EventBus'

wx.$bus = new EventBus()

page1.js

Page({
  <span class="hljs-function"><span class="hljs-title">onLoad</span>()</span>{
    wx.$bus.on(<span class="hljs-string">'add'</span>, <span class="hljs-built_in">this</span>.addHandler)
  },
  <span class="hljs-function"><span class="hljs-title">addHandler</span>(<span class="hljs-params">a, b</span>)</span>{
    <span class="hljs-built_in">console</span>.log(a+b)
  }
})

Page({

onLoad(){

wx.$bus.on('add', this.addHandler)

addHandler(a, b){

console.log(a+b)

}

})

page2.js

Page({
  <span class="hljs-function"><span class="hljs-title">onLoad</span>()</span>{
    wx.$bus.emit(<span class="hljs-string">'add'</span>, <span class="hljs-number">10</span>, <span class="hljs-number">20</span>)
  },
})

Page({

onLoad(){

wx.$bus.emit('add', 10, 20)

})

页面通信

getCurrentPages

getCurrentPages() 获取当前页面栈，数组中第一个元素为首页，最后一个元素为当前页面

元素为一个对象，里面存放着页面的信息，包括route（页面路径）、options（onLoad拿到的参数）、method、data等

Page({
  <span class="hljs-function"><span class="hljs-title">onLoad</span>()</span>{
    <span class="hljs-keyword">let</span> pages = getCurrentPages()
    <span class="hljs-keyword">let</span> lastPage = pages[pages.length-<span class="hljs-number">2</span>]
    lastPage.setData({
      <span class="hljs-attr">list</span>: []
    })
  }
})

Page({

onLoad(){

let pages = getCurrentPages()

let lastPage = pages[pages.length-2]

lastPage.setData({

list: []

})

}

})

写在最后

如果你还有其他的通信方式，欢迎交流~

关于作者

张舫

好好学习天天向上

微信小程序组件通讯方式

前言

组件通信

properties

triggerEvent

selectComponent

selectOwnerComponent

全局通信

globalData

storage

eventBus

简单实现

使用

页面通信

getCurrentPages

写在最后

关于作者

发表评论 取消回复

发表评论取消回复