请问大佬，为啥我模仿官方教程做@State后面的布尔值修改不了啊

@Entry
@Component
struct Index {
  @State message: string = 'Test'
  @State testColor : Boolean = true;
  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .fontColor(this.testColor ? Color.Blue : Color.Red)
      }
      .width('100%')
      .onClick(() => {
        this.testColor = !this.testColor;
        // this.message = '?';
        console.log(this.testColor ? 'true' : 'false');
      })
    }
    .height('100%')
  }
}