手势滑动退出HarmonyOS应用的规格

二次滑动退出应用可以参考如下Demo：

import common from '@ohos.app.ability.common';
import { promptAction } from '@kit.ArkUI';
@Entry
@Component
struct IndexComponent {
  @State textColor: Color = Color.Black;
  onPageShow() {
    this.textColor = Color.Blue;
    console.info('IndexComponent onPageShow');
  }
  onPageHide() {
    this.textColor = Color.Transparent;
    console.info('IndexComponent onPageHide');
  }
  firstBcakTimestamp: number = 0;
  onBackPress() {
    console.info('IndexComponent onBackPress');
    this.textColor = Color.Red;
    let now = Date.now();
    if (now - this.firstBcakTimestamp < 1000) {
      const context = getContext(this) as common.UIAbilityContext
      context.terminateSelf(); // 终止程序
    } else {
      this.firstBcakTimestamp = now;
      let option : promptAction.ShowToastOptions = {
        message: "是否继续退出" // 可以是$r图片
      }
      promptAction.showToast(option);
    }
    return true
  }
  build() {
    Column() {
      Text('Hello World')
        .fontColor(this.textColor)
        .fontSize(30)
        .margin(30)
    }.width('100%')
  }
}

退出应用非代码实现目前是一次就退出应用。请查看考如下文档：https://developer.huawei.com/consumer/cn/doc/design-guides/hmi-touchscreen-0000001928273206#section1442461065315