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【每日学点鸿蒙知识】人脸活体检测、NodeController刷新、自动关闭输入框、Row设置中间最大宽、WebView单例

article 2025/1/4 17:12:43

1、HarmonyOS 人脸活体检测调用？

H5调用应用侧方法可参考以下demo：

index.ets
Web()//注册方法
  .javaScriptProxy({
    object: this.testObj,
    name: "testObjName",
    methodList: ["getLocationTS"],
    controller: this.webController
  })

class testClass {
  constructor() {
  }

  async getLocationTS(): Promise<string> {
    //应用侧方法逻辑
  }
H5页面
<!DOCTYPE html>
<html>
<head>
    <link rel="stylesheet" type="text/css">
    <meta charset="UTF-8">
    <title>获取定位信息</title>
    <style>
        #prize {
            border-radius: 16px 16px 16px 16px;
            background-image: linear-gradient(180deg, #A2DAFF 0%, #EAF5FF 100%);
            margin-left: 1.82%;
            margin-top: 1.43%;
            width: 96.5%;
            height: 96.7%;
        }
    </style>
</head>
<body>
<div style="width:1000px;height:500px">
    <input style="width:1000px;height:100px;font-size:30px" id="inputText"/>
    <p style="width:1000px;height:100px;font-size:30px" id="demo">p1</p>
    <button style="width:1000px;height:100px" onclick="getLocation()">
        <span style="font-size:30px">获取定位</span>
    </button>
</div>

<script>
    function getLocation() {
<!--        ArtTS侧返回的如果是 promise对象，使用改方法处理 -->
<!--        具体可参考前端页面调用应用侧函数API，包含简单类型和复杂类型-->
<!--        https://developer.huawei.com/consumer/cn/doc/harmonyos-guides/web-in-page-app-function-invoking-0000001844832802-->
   <!-- H5侧方法调用 -->
        testObjName.getLocationTS()
        .then((param)=>{ document.getElementById("demo").innerHTML = "testObjName.getLocationTS()--"+JSON.stringify(param) })
        .catch((param)=>{ document.getElementById("demo").innerHTML = "testObjName.getLocationTS()--"+JSON.stringify(param) })
    }
</script>
</body>
</html>
}

2、HarmonyOS NodeController调用this.rebuild()后，画面没有刷新？

使用NodeController，首次进入页面，makeNode被自动回调，绘制出了3个题目框。之后外部调用onSelectBoxChange，更新了nodeArray并手动调用this.rebuild()，makeNode再次被回调，但是页面上并没有出现新绘制的框。

参考demo：

import { RenderNode, DrawContext, FrameNode, NodeController } from "@ohos.ArkUI.node"
import drawing from "@ohos.graphics.drawing"

class TextRenderNode extends RenderNode {
  async draw(context: DrawContext) {
    const canvas = context.canvas;
    const pen = new drawing.Pen();
    pen.setStrokeWidth(5);
    pen.setColor({alpha: 255, red: 255, green: 0, blue: 0});
    let path = new drawing.Path();
    path.moveTo(10,10);
    path.arcTo(10, 10, 200, 200, 0, 150);
    path.close();
    canvas.attachPen(pen);
    canvas.drawPath(path);
    canvas.detachPen();
  }
}

class MyNodeController extends NodeController {
  private rootNode: FrameNode | null = null;
  private nodeArray: Array<TextRenderNode> = []
  addMyNode(item:TextRenderNode){
    this.nodeArray.push(item)
  }

  makeNode(uiContext: UIContext): FrameNode | null {
    this.rootNode = new FrameNode(uiContext);
    const renderNode = this.rootNode.getRenderNode();
    if (renderNode === null) {
      return this.rootNode;
    }
    if (renderNode) {
      renderNode.clearChildren()
      this.nodeArray.forEach((item) => {
        renderNode.appendChild(item)
      })
    }
    return this.rootNode;
  }
  // onTouchEvent(event: TouchEvent): void {
  //   this.nodeArray.forEach((node, index) => { // this是undefined，无法获取到当前类的一些参数<---------
  //     console.log(JSON.stringify(this.nodeArray) + '德玛西亚')
  //   })
  // }
}

@Entry
@Component
struct Index {
  @State newNode:TextRenderNode = new TextRenderNode();
  @State nodeCV:MyNodeController = new MyNodeController()
  tempY = 0
  build() {
    Column() {
      Column() {
        NodeContainer(this.nodeCV)
          .width('100%')
          .height(200)
        Button('Invalidate')
          .onClick(() => {
            let newNode = new TextRenderNode()
            newNode.frame = { x: 0, y: this.tempY, width: 200, height: 100 }
            this.nodeCV.addMyNode(newNode)
            this.nodeCV.rebuild()
            this.tempY += 100
          })
      }
      .width('100%')
      .height('100%')
    }
    .height('100%')
  }
}

3、HarmonyOS TextInput输入的时候，当文字达到一定数量的时候，自动关闭输入框？

设置TextInput输入字符数量达到设定长度时自动关闭demo

@Entry
@Component
struct FirstTest {
  @State message1: string = 'Hello World';
  private controller:TextInputController = new TextInputController();

  build() {
    Column() {
      Text("FirstTest：" + this.message1)
        .fontSize(25)
        .fontWeight(FontWeight.Bold)

      TextInput({placeholder:'Waiting for input',text:$$this.message1,controller:this.controller})
        .fontSize(25)
        .fontWeight(FontWeight.Bold)
        .onChange(()=>{
          if(this.message1.length >= 20){
            this.controller.stopEditing()
          }
        })

    }
  }
}

4、HarmonyOS Row 怎么设置中间最大宽度？

Row 怎么设置中间最大宽度
使用constraintSize({maxWidth: Infinity})来对尺寸范围限制

5、HarmonyOS 如何创建单例的WebView组件？

只可以创建单例的对象，示例:

export class GlobalContext {
  private constructor() {
  }

  private static instance: GlobalContext;
  private _objects = new Map<string, Object>();

  public static getContext(): GlobalContext {
    if (!GlobalContext.instance) {
      GlobalContext.instance = new GlobalContext();
    }
    return GlobalContext.instance;
  }

  getObject(value: string): Object | undefined {
    return this._objects.get(value);
  }

  setObject(key: string, objectClass: Object): void {
    this._objects.set(key, objectClass);
  }
}

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