Web Development

How does the return result of onUrlLoadIntercept affect onInterceptRequest in the <Web> component?

Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)

Solution

The operation that follows onUrlLoadIntercept is subject to its return result.

  • If true is returned, the URL request is intercepted.
  • If false is returned , the onInterceptRequest callback is performed.

Reference

onUrlloadIntercept

What should I do if the onKeyEvent event of the <Web> component is not triggered as expected?

Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)

Problem

The onKeyEvent event is set for the <Web> component to listen for keyboard events. However, it is not triggered when a key is pressed or lifted.

Solution

Currently, the <Web> component does not support the onKeyEvent event. To listen for keyboard events for the <Web> component, you can use the onInterceptKeyEvent callback function.

Reference

onInterceptKeyEvent

What should I do if page loading fails when onInterceptRequest is used to intercept URLs and return the custom HTML file?

Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)

Problem

The onInterceptRequest API intercepts URLs specified by src and returns the custom HTML file. However, the content in the script tag in the HTML file is not loaded.

Solution

If only setResponseData is set for the interceptor, the kernel cannot identify the HTML file. You must also set parameters such as setResponseEncoding, setResponseMimeType, and setResponseHeader for the kernel to identify the HTML file.

Example

Web({ src: 'www.example.com', controller: this.controller })
  .onInterceptRequest((event) => {
    console.log('url:' + event.request.getRequestUrl())
    this.responseweb = new WebResourceResponse();
    var head1:Header = {
      headerKey:"Connection",
      headerValue:"keep-alive"
    }
    var length = this.heads.push(head1)
    this.responseweb.setResponseHeader(this.heads)
    this.responseweb.setResponseData(this.webdata)
    this.responseweb.setResponseEncoding('utf-8')
    this.responseweb.setResponseMimeType('text/html')
    this.responseweb.setResponseCode(200)
    this.responseweb.setReasonMessage('OK')
    return this.responseweb
})

Reference

WebResourceResponse

How do I execute JS functions in HTML in ArkTS code?

Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)

Solution

Use the runJavaScript API in WebviewController to asynchronously execute JavaScript scripts and obtain the execution result in a callback.

NOTE

runJavaScript can be invoked only after loadUrl is executed. For example, it can be invoked in onPageEnd.

Reference

runJavaScript

How do I invoke an ArkTS method on a local web page loaded in the <Web> component?

Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)

Solution

  1. Prepare an HTML file. Below is the sample code:

    <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <h1>Title</h1>
    <h5 id="h5"></h5>
    <h5 id = "h6"></h5>
    <button onclick="handleFromH5">Invoke ArkTS method </button>
    <script type="text/javascript">
        function handleFromH5(){
            let result = window.objName.test();
            document.getElementById('h6').innerHTML = result;
        }
    </script>
</body>
</html>

  2. Use the JavaScriptProxy API in ArkTs to register the object in ArkTS with the window object of H5, and then use the window object to call the method in H5. In the following example, the testObj object in ArkTS is registered with the window object of H5 with the alias objName. In H5, window.objName can then be used to access the object.

    // xxx.ets
import web_webview from '@ohos.web.webview'
@Entry
@Component
struct Index {
  @State message: string = 'Hello World'
  controller: web_webview.WebviewController = new web_webview.WebviewController()
  testObj = {
    test: (data1, data2, data3) => {
      console.log("data1:" + data1);
      console.log("data2:" + data2);
      console.log("data3:" + data3);
      return "AceString";
    },
    toString: () => {
      console.log('toString' + "interface instead.");
    }
  }
  build() {
    Row() {
      Column() {
        Web({ src:$rawfile('index.html'), controller:this.controller })
          .javaScriptAccess(true)
          .javaScriptProxy({
            object: this.testObj,
            name: "objName",
            methodList: ["test", "toString"],
            controller: this.controller,
         })
      }
      .width('100%')
    }
    .height('100%')
  }
}

Reference

javaScriptProxy

How do I set the domStorageAccess attribute of the <Web> component?

Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)

Solution

The domStorageAccess attribute sets whether to enable the DOM Storage API. By default, this feature is disabled.

Reference

domStorageAccess

What should I do if the network status fails to be detected on the HTML page loaded by the <Web> component?

Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)

Problem

When window.navigator.onLine is used on the HTML page to obtain the network status, the value is false no matter the network connection is set up or not.

Solution

Configure the permission for the application to obtain network information: ohos.permission.GET_NETWORK_INFO.

Reference

GET_NETWORK_INFO

How do I set the UserAgent parameter through string concatenation?

Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)

Solution

By default, the value of UserAgent needs to be obtained through the WebviewController. Specifically, it is obtained by calling the getUserAgent API in a WebviewController object after it is bound to the <Web> component. Therefore, to set UserAgent through string concatenation before page loading:

  1. Use @State to define the initial UserAgent parameter and bind it to the <Web> component.
  2. In the onUrlLoadIntercept callback of the <Web> component, use WebviewController.getUserAgent() to obtain the default UserAgent value and update the UserAgent bound to the <Web> component.

Example

import web_webview from '@ohos.web.webview'
@Entry
@Component
struct Index {
  private controller: web_webview.WebviewController = new web_webview.WebviewController()
  @State userAgentPa: string = ''
  build() {
    Row() {
      Column() {
        Web({ src: 'http://www.example.com', controller: this.controller }) // Replace the URL with the actual URL.
          .width('100%')
          .userAgent(this.userAgentPa)
          .onUrlLoadIntercept((event) => {
            let userAgent = this.controller.getUserAgent();
            this.userAgentPa = userAgent + ' 111111111'
            return false;
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}

Reference

userAgent, getUserAgent

How do I enable the <Web> component to return to the previous web page following a swipe gesture?

Applicable to: OpenHarmony 3.2 Beta 5 (API version 9)

Solution

Override the onBackPress API to define the return logic and use WebviewController to determine whether to return to the previous web page.

Example

import web_webview from '@ohos.web.webview';
@Entry
@Component
struct Index {
  controller: web_webview.WebviewController = new web_webview.WebviewController();
  build() {
    Column() {
      Web({ src: 'http://www.example.com', controller: this.controller })// Replace the URL with the actual URL.
    }
  }
  onBackPress() {
    // Check whether a specific number of steps forward or backward can be performed on the current page. A positive number indicates forward, and a negative number indicates backward.
    if (this.controller.accessStep(-1)) {
      this.controller.backward(); // Return to the previous web page.
      // Execute the custom return logic.
      return true
    } else {
      // Execute the default return logic to return to the previous page.
      return false
    }
  }
}

Reference

accessStep

Does WebView support same-layer rendering (API version 10)?

Solution

  1. WebView, Video, Map, Camera, Canvas, and WebGL all support same-layer rendering.
  2. The id, type, src, width, height, and url attributes of web embedded tags can be transferred to native components.

What debugging tools does WebView provide? How do I use them? (API version 10)

Solution

The <Web> component supports debugging of web frontend pages by using DevTools, a web frontend development and debugging tool that allows you to debug an application's frontend pages on a PC. Before you do this, use setWebDebuggingAccess() to enable frontend page debugging for the <Web> component and make sure the test device connected to the PC runs 4.1.0 or a later version.

Reference

Debugging Frontend Pages by Using DevTools

How do I use WebView to implement request interception? (API version 10)

Solution

You can call onInterceptRequest() to customize web page responses, file resource responses, and more. When a resource loading request is initiated on a web page, the application layer will receive the request. The application layer then constructs a local resource response and sends it to the web kernel. On receiving the response, the web kernel parses the response and loads page resources accordingly.

Reference

Customizing Page Request Responses

How does WebView communicate with the native side? (API version 10)

Solution

  1. For communication from the native side to the HTML5 side, use the runJavaScript API. For communication from the HTML5 side to the native side, use the registerJavaScriptProy API. Register the native method with the HTML5 side, and then from the HTML5 side call the frontend method to communicate with the native side.
  2. Both runJavaScript and registerJavaScriptProy are exposed in the C API on the NDK side.
  3. The onInterceptrequest API is used to intercept requests from the HTML5 side and return native data as a response to the HTML5 side. In this way, the implement communication between the native side and HTML5 side is implemented.

Reference

runJavaScript, registerJavaScriptProxy, javaScriptProxy, onInterceptRequest