Marquee组件使用问题有哪些？

import measure from '@ohos.measure';  
  
@Entry  
@Component  
struct TextDemo {  
  string1: string = 'start|测试文本测试文本测试文本测试文本测试文本测试文本测|end'  
  string2: string ='start|测试文本2测试文本2测试文本2测试文本2测试文本2测试|end'  
  @State src: string = this.string1  
  @State textOffset: number = 0  
  @State textWidth: number = measure.measureText({  
    textContent: this.src,  
    fontWeight: FontWeight.Medium,  
  })  
  private columnWidth: number = 300;  
  
  @State finishFlag:boolean = false;  
  @State iterations:number = 1  
  
  build() {  
    Row() {  
      Column() {  
        Column() {  
          if(this.finishFlag){  
            Text(this.src)  
              .width(px2vp(this.textWidth))  
              .maxLines(1)  
              .fontWeight(FontWeight.Medium)  
              .textAlign(TextAlign.Center)  
              .offset({ x: 0 })  
              .onAppear(() => {  
                this.textOffset = 0  
                this.textWidth = measure.measureText({  
                  textContent: this.src,  
                  fontWeight: FontWeight.Medium,  
                })  
                this.finishFlag = !this.finishFlag  
              })  
          }else {  
            Text(this.src)  
              .width(px2vp(this.textWidth))  
              .maxLines(1)  
              .fontWeight(FontWeight.Medium)  
              .textAlign(TextAlign.Center)  
              .offset({ x: this.textOffset })  
              .animation({  
                duration: 5000,  
                iterations: this.iterations,  
                curve: Curve.Linear,  
                onFinish: () => {  
                  //动画播放完的回调  
                  if(this.src === this.string1){  
                    this.src = this.string2  
                  }else{  
                    this.src = this.string1  
                  }  
                  this.finishFlag = !this.finishFlag  
                }  
              })  
              .onAppear(() => {  
                this.textOffset = -px2vp(this.textWidth) + this.columnWidth  
              })  
          }  
        }  
        .alignItems(HorizontalAlign.Start)  
        .backgroundColor(Color.Pink)  
        .clip(true)  
        .width(this.columnWidth)  
      }  
      .width('100%')  
    }  
    .height('100%')  
  }  
}