HarmonyOS 如何动态计算Text的高度

ArkUI有提供文本计算的功能，可计算指定文本单行布局下的宽度和高度，

参考API：

https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-measure-V5#measuremeasuretext

以下demo是使用该API实现文本展开折叠的功能，供参考：

import measure from '@ohos.measure'
@Entry @Component struct MeasurePage {
  @State rawTitle: string = "1月16日，国务院新闻办公室举行新闻发布会，介绍2024年春运形势及工作安排。从2月9日（除夕）00：00到2月17日（正月初八）24：00，免费9天。1月16日，国务院新闻办公室举行新闻发布会，介绍2024年春运形势及工作安排"
  //@State rawTitle: string = "1月16日，国务院新闻办公室举行新闻发布会"
  @State title: string = this.rawTitle
  @State suffixStr: string = ""
  expanded: Boolean = true
  titleWidth: number = 350
  needProcess: boolean = true
  ellipsis: string = "..."
  EXPAND_STR: string = "展开"
  COLLAPSE_STR: string = "收起"
  MAX_LINES: number =2; fontSize:number = 16
  aboutToAppear(): void {
    this.process();
  }
  process(): void {
    if (this.expanded) {
      this.collapseText();
    } else {
      this.expandText();
    }
  }
  expandText(): void {
    console.log('testTag: ' + this.needProcess);
    if (this.needProcess) {
      this.suffixStr = this.COLLAPSE_STR;
      //收起
      this.expanded = true; this.title = this.rawTitle;
    }
  }

  collapseText(): void {
    if (!this.needProcess) { return; }
    let titleSize : SizeOptions = measure.measureTextSize({
      textContent: this.rawTitle,
      constraintWidth: this.titleWidth,
      fontSize: this.fontSize
    })
    let twoLineSize : SizeOptions = measure.measureTextSize({
      textContent: this.rawTitle, constraintWidth:
      this.titleWidth, fontSize: this.fontSize,
      maxLines: this.MAX_LINES
    })
    //文本未超过限制行数，不进行展开、收起处理
    if ((titleSize.height as number) == (twoLineSize.height as number)) {
      this.needProcess = false; return;
    }
    console.log('test row height:' + titleSize.height)
    console.log('test twoLineSize height:' + twoLineSize.height)
    let clipTitle: string = this.rawTitle
    this.suffixStr = this.EXPAND_STR;
    while ((titleSize.height as number) > (twoLineSize.height as number)) {
      this.expanded = true; // 可以修改其他计算算法提高性能
      clipTitle = clipTitle.substring(0, clipTitle.length - 1);
      titleSize = measure.measureTextSize({
        // textContent: clipTitle + this.ellipsis + this.suffixStr,
        textContent: clipTitle + this.ellipsis ,
        constraintWidth: this.titleWidth, fontSize: this.fontSize
      })
      console.log("test while clipTitle:" + clipTitle)
      console.log("test while clipTitle height:" + titleSize.height)
    }
    console.log("test clipTitle:" + clipTitle)
    this.title = clipTitle + this.ellipsis
    this.expanded = false;
  }
  build() {
    Row() {
      Column() {
        Text(){ Span(this.title) }
        .fontSize(this.fontSize)
        .id("title")
        .width(this.titleWidth)
        if (this.needProcess) {
          Text(this.suffixStr)
            .fontColor(Color.Orange)
            .onClick((event) => {
              this.process();
            })
        }
      }.width('100%').alignItems(HorizontalAlign.Start) } .height('100%')
  }
}
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