UniApp design and development skills for implementing custom filters and data processing

UniApp is a development tool based on the Vue.js framework, which can compile a set of codes into multiple platform applications at the same time, such as WeChat applets, H5 pages, Apps, etc. In UniApp, we can customize filters and perform data processing to achieve more flexible and efficient development.

1. Design and development of custom filters

1.1 The function and principle of filters

A filter is a function that converts and processes data formats. Common application scenarios include date formatting, data thousandth separation, price formatting, etc. In UniApp, filters are created using the filter method provided by the Vue.js framework.

The principle of the filter is very simple. It will receive an input value, followed by the pipe operator |, followed by the name of the filter, and then convert the input value to the output value. For example:

{{ inputValue | filterName }}

1.2 Create a custom filter

In the UniApp project, we can create a filters folder in the common directory , and then create an index.js file to define all filters. Suppose we need to implement a time formatting filter, we can follow the following steps:

First, in the index.js file, introduce Vue.js:

import Vue from 'vue'

Then, create a filter named formatDate:

Vue.filter('formatDate', function (value, format) {
  // 根据format参数进行格式化处理
  // ...
  return formattedValue
})

Finally, export the Vue instance:

export default Vue

1.3 Use custom filters in the page

In the page, we can use custom filters through the |pipeline operator. For example, if we want to format the timestamp into the form of "yyyy-MM-dd hh:mm:ss", we can follow the following steps:

First, introduce a custom filter:

import Vue from '@/common/filters'

Then, call where the filter needs to be used:

<template>
  <view>
    <text>{{ timestamp | formatDate('yyyy-MM-dd hh:mm:ss') }}</text>
  </view>
</template>

2. Design and development skills of data processing

2.1 The role and principle of data processing

Data Processing refers to processing and processing the data returned by the API so that it can be better displayed and used on the page. In UniApp, data processing can be achieved through the computed attribute of Vue.js.

The principle of data processing is to monitor the specified data changes, then perform corresponding processing and calculations based on the changed data, and return the calculated results. In this way, we can use the processed data directly in the page without maintaining a large amount of logic code.

2.2 Create calculated properties

In the page component of UniApp, we can create calculated properties through the computed property to achieve data processing and processing. Suppose we need to calculate the discount price of the product price, we can follow the following steps:

First, define the original price and discount of the product in the data attribute of the page:

data() {
  return {
    originalPrice: 100.00,
    discount: 0.8
  }
}

Then, create a calculated attribute named discountPrice:

computed: {
  discountPrice() {
    return this.originalPrice * this.discount
  }
}

Finally, use the calculated attribute in the page:

<template>
  <view>
    <text>商品价格：{{ originalPrice }}</text>
    <text>折扣价：{{ discountPrice }}</text>
  </view>
</template>

2.3 Monitor data changes

If you need to perform some specific operations when the data changes, you can monitor the data changes through the watch attribute. Suppose we need to pop up a prompt box when the price of the product changes. We can follow the following steps:

First, define the price of the product in the data attribute of the page:

data() {
  return {
    price: 100.00
  }
}

Then, create a listener named price:

watch: {
  price(newPrice, oldPrice) {
    uni.showToast({
      title: `商品价格变化：${oldPrice} -> ${newPrice}`,
      icon: 'none'
    })
  }
}

Finally, use the price input box on the page and bind the v-model command:

<template>
  <view>
    <input v-model="price" type="number" placeholder="请输入商品价格" />
  </view>
</template>

3. Complete sample code

The following is a complete sample code that demonstrates how to implement custom filters and data processing in UniApp:

// common/filters/index.js

import Vue from 'vue'

Vue.filter('formatDate', function (value, format) {
  // 根据format参数进行格式化处理
  // ...
  return formattedValue
})

export default Vue

// pages/home/index.vue

<template>
  <view>
    <text>{{ timestamp | formatDate('yyyy-MM-dd hh:mm:ss') }}</text>
    <input v-model="price" type="number" placeholder="请输入商品价格" />
    <text>商品价格：{{ price }}</text>
    <text>折扣价：{{ discountPrice }}</text>
  </view>
</template>

<script>
import Vue from '@/common/filters'

export default {
  data() {
    return {
      timestamp: Date.now(),
      price: 100.00,
      discount: 0.9
    }
  },
  computed: {
    discountPrice() {
      return this.price * this.discount
    }
  },
  watch: {
    price(newPrice, oldPrice) {
      uni.showToast({
        title: `商品价格变化：${oldPrice} -> ${newPrice}`,
        icon: 'none'
      })
    }
  }
}
</script>

The above is about This introduction to the design and development techniques for implementing custom filters and data processing in UniApp, I hope it will be helpful to everyone in UniApp development. With custom filters and data processing, we can handle data more flexibly and provide a better user experience.

The above is the detailed content of UniApp design and development skills for implementing custom filters and data processing. For more information, please follow other related articles on the PHP Chinese website!