How to use header component-Mini Program Development-php.cn

How to use header component

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Release： 2018-03-23 10:39:54

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This time I will bring you the method of using the header component, what are the precautions when using the header component, the following is a practical case, let's take a look.

1. Data transfer in header component development

1. App.vue introduces components

import header from './components/header/header'

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2. Registers components in App.vue

 export default {
   components:{
     v-header:header
   }
 }

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3. Use components

<v-header :sell="sellerObj"></v-header>

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Explanation: :sell="sellerObj", here it is treated as a formal parameter just like a function passing parameters, sellerObj is the actual parameter, then the parent component actual parameter How is it passed to the child component, and through what method

4. Parent component passes data to the child component

In the parent component, sellerObj needs to be exported as data, and the child component passes props from the parent component Get data from, and specify the data type

export default {
 props:{ // 子组件获取 父组件 数据
 sell:{
  type:Object // 传递的类型 
 }
 }
 }

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Summary:

The child component creates a property in props to receive the parent component The passed value
Register the subcomponent in the parent component
Add the properties created in the subcomponent props to the subcomponent tag
Assign the value that needs to be passed to the subcomponent to the attribute

5. Calling data

<p class="logo">
 <img :src="sell.avatar" alt="" width=&#39;64&#39; height=&#39;64&#39;/>
</p>
<span class="name">{{sell.name}}</span>
<p class="description">
  {{sell.description + '/' + sell.deliveryTime + '分钟送达'}}
</p>

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Details:

support Add v-if ='sell.supports' when binding data

Reason: Before we get the data through axios, we create an empty object sellerObj in the parent component and pass it to the child component first. If no data is transmitted at first, an underfined error will be reported. With v-if, if the data cannot be received, it will not be parsed, and no error will be reported.

2. Header component pop-up layer (details)

1. Pop-up mask layer

(1) Set one Status, determine the status to control the display and hiding

data (){
 return {
 detailShow:false
 }
}

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<p v-if="detailShow" class="detail"></p>

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(2) Bind the click event, change the status through the methods method, and control the visible and hidden effect

<p class="bulletin-wrapper" @click="showDetails()" ></p>
<p class="detail-close" v-if="sell.supports">
  <i class="icon-close" @click="hideDetail()"></i>
</p>

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methods:{
 showDetails () {
  this.detailShow=true
 },
 hideDetail () {
 this.detailShow=false
 }
}

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2. Star rating

(1) Bind class to control the type of star size

// 利用 computed 属性
<p class="star" :class="starSizeType"></p>

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computed: {
 starSizeType() { // 返回 星级的大小类型 48/36/24
  return 'star-' + this.size;
 }
}

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(2) Traverse the number of stars

Copy code The code is as follows:

(3) Define constants to control the status of each star

// 类名用变量存起来
const LENGTH = 5 // 星星长度
const CLS_ON = 'on' // 全星
const CLS_HALF = 'half' // 半星
const CLS_OFF = 'off'// 空星

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(4) Determine the type of each span through calculation

itemClasses () { // 返回一个数组为每个span 的类名 （遍历）
  let spanClassList=[];
  // 利用 实参评分来判断 有几颗全星，半星，空星
 let scores=( Math.floor(this.score * 2) ) / 2 
 let intNum= Math.floor(scores); // 全星个数 
 let HashalfNum= scores % 1 !== 0  // 半星
 for(var i=0;i<intNum;i++){ // 遍历全星的span
 spanClassList.push(CLS_ON)
 }
 if(HashalfNum){ // 如果有半星 加类名
 spanClassList.push(CLS_HALF)
 }
 while(spanClassList.length<LENGTH){// 判断 是否有空星 及个数
 spanClassList.push(CLS_OFF)
 }
  return spanClassList;   
 }
}

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(5) By dynamically binding class Add a class name to span

<p class="star" :class="starSizeType">
 <span v-for="itemClass in itemClasses" :class="itemClass" class="star-item" track-by="$index"></span>
</p>

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I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the PHP Chinese website!