#鸿蒙通关秘籍#如何更新BuilderNode中的原生组件树？

更新BuilderNode中的组件树，需要调用BuilderNode的update方法，同时更新的数据必须符合状态管理的定义。例如，状态变量应定义为@Prop或@ObjectLink以跟踪更新。

import { NodeController, BuilderNode, FrameNode, UIContext } from "@kit.ArkUI"

class Params {
  text: string = ""
  constructor(text: string) {
    this.text = text;
  }
}

// 自定义组件
@Component
struct TextBuilder {
  @Prop message: string = "TextBuilder";

  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .margin({ bottom: 36 })
          .backgroundColor(Color.Gray)
      }
    }
  }
}

@Builder
function buildText(params: Params) {
  Column() {
    Text(params.text)
      .fontSize(50)
      .fontWeight(FontWeight.Bold)
      .margin({ bottom: 36 })
    TextBuilder({ message: params.text })
  }
}

class TextNodeController extends NodeController {
  private textNode: BuilderNode<[Params]> | null = null;
  private message: string = "";

  constructor(message: string) {
    super()
    this.message = message
  }

  makeNode(context: UIContext): FrameNode | null {
    this.textNode = new BuilderNode(context);
    this.textNode.build(wrapBuilder<[Params]>(buildText), new Params(this.message))
    return this.textNode.getFrameNode();
  }

  update(message: string) {
    if (this.textNode !== null) {
      this.textNode.update(new Params(message));
    }
  }
}

@Entry
@Component
struct Index {
  @State message: string = "hello"
  private textNodeController: TextNodeController = new TextNodeController(this.message);
  private count = 0;

  build() {
    Row() {
      Column() {
        NodeContainer(this.textNodeController)
          .width('100%')
          .height(200)
          .backgroundColor('#FFF0F0F0')
        Button('Update')
          .onClick(() => {
            this.count += 1;
            const message = "Update " + this.count.toString();
            this.textNodeController.update(message);
          })
      }
      .width('100%')
      .height('100%')
    }
    .height('100%')
  }
}