How does Uniapp send page requests?

Preface

With the rapid development of the mobile Internet, mobile applications are receiving more and more attention. In order to make it easier for developers to develop applications that run on multiple platforms at the same time, Uniapp came into being. Uniapp is a cross-platform development tool developed based on the Vue.js framework. It can run on multiple platforms such as iOS, Android, H5, and mini programs. This article will discuss how in Uniapp, when we enter a certain page, Uniapp will send a page request.

The principle of Uniapp sending page requests

When we enter a page in Uniapp, it actually jumps through the Vue-router routing mechanism. Routing refers to displaying different page content based on different URL addresses. It is one of the core parts of web applications. In Uniapp, Vue-router will convert the URL address that needs to be redirected into the corresponding components, and then mount these components to the corresponding pages.

When we enter a page, Uniapp will request the corresponding data based on the URL address of the current page, and then render the data to the page. These data can be API interface data from the server or data from local storage. In order to implement the page request function, we need to use some related API interfaces in Uniapp. These API interfaces are:

1. Uni.request(options)

Uni. request(options) is used to initiate a network request. Its parameter options have the following attributes:

• url: the requested address.
• data: Request parameters, types are Object, ArrayBuffer, ArrayBufferView, Blob, Document, FormData, etc.
• Header: Set the header of the request, the type is Object.
• method: Request method, such as GET, POST, PUT, etc. The default is GET.
• dataType: The data format expected to be returned, such as json, text, html, etc., the default is json.
• responseType: response data type, such as arraybuffer, blob, document, json, text, etc. The default is text.

Uni.request(options) returns a Promise instance. The caller can use the then() method to process the response data after the request is successful, or use the catch() method to handle the request exception.

2. Uni.showLoading(options)

Uni.showLoading(options) is used to display the loading prompt box. Its parameter options has the following attributes:

• title: The title of the prompt box.
• mask: Whether to display the background mask layer.
• duration: The display time of the prompt box, in milliseconds, the default is 2000.

Uni.showLoading(options) returns a Promise instance. The caller can use the then() method to process the logic after successful display, or use the catch() method to process the logic after display failure.

3. Uni.hideLoading()

Uni.hideLoading() is used to hide the loading prompt box. After calling it, the loading prompt box will disappear.

Application Scenario

In actual development, we usually send a request when entering a certain page to obtain the data required by the page and render the data onto the page. The following is a simple example:

// 在某个页面中发送请求
export default {
  data() {
    return {
      list: []
    }
  },
  onLoad() {
    Uni.showLoading({
      title: '正在加载...'
    })
    Uni.request({
      url: 'http://your.api.com', // 接口地址
      method: 'GET',
      dataType: 'json'
    }).then(res => {
      this.list = res.data // 将返回数据赋值给list属性
    }).catch(err => {
      console.log('请求失败', err)
    }).finally(() => {
      Uni.hideLoading()
    })
  }
}

In the above example, we use the Uni.showLoading() method to display the loading prompt box when the page is loaded, and then use the Uni.request() method to send a request and obtain the interface Data and assign the data to the list attribute of the page. Finally, use the Uni.hideLoading() method to hide the loading prompt box.

Conclusion

Through the explanation of this article, I believe that everyone has a certain understanding of the principle and use of Uniapp sending page requests. In actual development, we can flexibly use these APIs to optimize the request and rendering process as much as possible to improve the user experience of the application.

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