HarmonyOS Toggle绑定onChange事件设置APP深色模式无效

import { ConfigurationConstant } from '@kit.AbilityKit';  
@Entry  
@Component  
struct ToggleExample {  
 @Watch('changeColorMode') @State isOn:boolean = false  
  build() {  
    Column() {  
      Row() {  
        Toggle({ type: ToggleType.Switch,isOn:this.isOn })  
          .margin({left: 200, right: 10})  
          .onChange(()=>{  
            this.isOn = !this.isOn  
          })  
      }  
    }  
  }  
  changeColorMode(){  
    let context = getContext(this).getApplicationContext()  
    context.setColorMode(this.isOn? ConfigurationConstant.ColorMode.COLOR_MODE_DARK:ConfigurationConstant.ColorMode.COLOR_MODE_LIGHT)  
  
  }  
}