HarmonyOS 在弹出的自定义Dialog中，需要点击按钮跳转到另一个全屏的页面，这个页面显示在了dialog的下层

目前无法做到新页面覆盖在弹窗上，因为弹窗与页面不绑定，属于独立的一层。建议使用stack模拟实现dialog的效果。

可以通过Stack堆叠布局覆盖在原有的page上面来模拟dialog的效果，stack文档：https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/arkts-layout-development-stack-layout-V5

stack拟态弹窗参考demo：

@Entry
@Component
struct Index {
  @State bottomOpacity: number = 1;
  @State topOpacity: number = 0;

  popShow() {
    console.info("Pop show ...");
    if (this.topOpacity === 1) {
      return;
    }
    console.info("Pop show start ...");
    this.bottomOpacity = 0.6;
    this.topOpacity = 1;
    console.info("Pop show end ...");
  }

  popHide(): void {
    console.info("Pop hide ...");
    if (this.topOpacity === 0) {
      return;
    }
    console.info("Pop hide start ...");
    this.bottomOpacity = 1;
    this.topOpacity = 0;
    console.info("Pop hide end ...");
  }

  build() {
    Stack({ alignContent: Alignment.Bottom }) {
      Column() {
        Text('First child, show in level 1')
          .width('60%')
          .height('20%')
          .align(Alignment.Center)
      }
      .width('100%')
      .height('100%')
      .backgroundColor(0xd2cab3)
      .justifyContent(FlexAlign.Center)
      .opacity(this.bottomOpacity)
      this.popup();
      Button('Click Me')
        .width('40%')
        .height('10%')
        .backgroundColor(Color.Green)
        .zIndex(3)
        .onClick(() => this.popShow())
    }
    .width('100%')
    .height('100%')
    .margin({ top: 5 })
  }

  @Builder popup() {
    if (this.topOpacity === 1) {
      Column() {
        Text('Second child, show in level2')
          .width('70%')
          .height('20%')
          .align(Alignment.Center)
      }
      .width('70%')
      .height('20%')
      .backgroundColor(0xc1cbac)
      .justifyContent(FlexAlign.Center)
      .position({
        x: 50,
        y: 90
      })
      .opacity(this.topOpacity)
      .onClick(() => this.popHide())
    }
  }
}