HarmonyOS鸿蒙Next中手表如何实现增加主题背景切换

开发者你好，可以使用animation属性动画实现上述动画效果，具体可以参考以下demo：

@Entry
@Component
struct test {
  @State widthSize: number | string = 20;
  @State heightSize: number | string = 20;

  build() {
    Column() {
      Text('top');

      Stack({ alignContent: Alignment.Start }) {
        Column()
          .width(this.widthSize) // 只有写在animation前面才生效
          .height(this.heightSize) // 只有写在animation前面才生效
          .animation({
            duration: 500,
            curve: Curve.EaseOut,
            iterations: 1,
            playMode: PlayMode.Normal
          })
          .borderRadius(20)
          .backgroundColor('#ffde4444');

        Column() {
          Text('color');
        }
        .justifyContent(FlexAlign.Center)
        .borderRadius(20)
        .height('100%')
        .width('100%')
        .backgroundColor('#2ab0a9a9');
      }
      .height('10%')
      .width('90%')
      .onClick(() => {
        this.widthSize === 20 ? this.widthSize = '100%' : this.widthSize = 20;
        this.heightSize === 20 ? this.heightSize = '100%' : this.heightSize = 20;
      });

      Text('bottom');
    }
    .height('100%')
    .width('100%');
  }
}