HarmonyOS 背景渐变色linearGradient怎么通过@State里定义的对象动态取值动态改变渐变色

示例参考如下：

import { HashMap } from '@kit.ArkTS'

@Entry
@Component
struct Index {
  @State themeName: string = ''
  @State GradientBg: Array<[ResourceColor, number]> = new Array();
  @State GradientBgMap: HashMap<string, Array<[ResourceColor, number]>> =
    new HashMap<string, Array<[ResourceColor, number]>>()

  aboutToAppear(): void {
    this.GradientBgMap.set("name1", [['#ffe3d236', 0.0], ['#ff5bb8b8', 0.5], ['#ffbf4cba', 1.0]])
    this.GradientBgMap.set("name2", [['#ff3684e3', 0.0], ['#ff545f5f', 0.5], ['#ff5cd013', 1.0]])
    this.themeName = 'name1'
    this.GradientBg = this.GradientBgMap.get("name1")
  }

  build() {
    Column() {
      Button("点击切换渐变背景属性")
        .onClick(() => {
          if (this.themeName == 'name1') {
            this.GradientBg = this.GradientBgMap.get("name2")
            this.themeName = 'name2'
          } else {
            this.GradientBg = this.GradientBgMap.get("name1")
            this.themeName = 'name1'
          }
        })
      Row()
        .width('90%')
        .height(130)
        .backgroundColor(Color.White)
        .borderRadius(14)
        .linearGradient({
          angle: 180,
          colors: this.GradientBg
        })
    }
  }
}