HarmonyOS 5折叠屏设备的自适应广告位布局方案

以下为 ​​HarmonyOS 5折叠屏设备自适应广告位布局的完整技术方案​​，包含动态布局、折叠状态感知和性能优化的代码实现：

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1. 系统架构

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2. 核心模块实现

2.1 折叠状态监听

// fold-state.ets
import window from '@ohos.window';

class FoldStateMonitor {
  private static currentState: WindowFoldState = 'UNKNOWN';

  static startListening(): void {
    window.on('foldStateChange', (state) => {
      this.currentState = state;
      EventBus.emit('foldChange', state);
    });
  }

  static getCurrentState(): WindowFoldState {
    return this.currentState;
  }
}

2.2 响应式广告容器

// ad-container.ets
@Component
struct AdaptiveAdContainer {
  @State layoutMode: 'EXPANDED' | 'FOLDED' = 'EXPANDED';

  aboutToAppear() {
    FoldStateMonitor.startListening();
    EventBus.on('foldChange', (state) => {
      this.layoutMode = state === 'FULL' ? 'EXPANDED' : 'FOLDED';
    });
  }

  build() {
    Column() {
      if (this.layoutMode === 'EXPANDED') {
        ExpandedAdBanner()
      } else {
        SplitAdBanner()
      }
    }
  }
}

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3. 布局策略实现

3.1 大屏模式布局（展开状态）

// expanded-ad.ets
@Component
struct ExpandedAdBanner {
  @Prop adContent: AdContent;

  build() {
    GridContainer({
      columns: 3,
      rowHeight: 200
    }) {
      ForEach(this.adContent.items, item => {
        GridItem() {
          AdCard(item)
        }
      })
    }
    .onClick(() => this._trackImpression())
  }
}

3.2 分屏模式布局（折叠状态）

// split-ad.ets
@Component
struct SplitAdBanner {
  @Prop adContent: AdContent;

  build() {
    Swiper() {
      ForEach(this.adContent.items, item => {
        SwiperItem() {
          CompactAdCard(item)
        }
      })
    }
    .indicator(true)
    .autoPlay(true)
  }
}

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4. 广告内容适配

4.1 资源动态选择

// asset-selector.ets
class AdAssetSelector {
  static getAssets(adId: string, mode: WindowFoldState): AdAssets {
    const suffix = mode === 'FULL' ? '_lg' : '_sm';
    return {
      image: `${adId}${suffix}.jpg`,
      video: mode === 'FULL' ? `${adId}.mp4` : null,
      text: this._getAdaptiveText(adId, mode)
    };
  }

  private static _getAdaptiveText(adId: string, mode: WindowFoldState): string {
    return mode === 'FULL' ? 
      AdDatabase.getFullDescription(adId) :
      AdDatabase.getShortDescription(adId);
  }
}

4.2 交互热区调整

// touch-adapter.ets
class AdTouchAdapter {
  static getHitRect(mode: WindowFoldState): Rect {
    return mode === 'FULL' ? 
      { x: 0, y: 0, width: 1.0, height: 0.3 } : 
      { x: 0, y: 0, width: 0.8, height: 0.4 };
  }
}

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5. 性能优化

5.1 广告预加载

// ad-preloader.ets
class AdPreloader {
  private static cache = new Map<string, AdContent>();

  static async preload(adIds: string[]): Promise<void> {
    await Promise.all(adIds.map(async id => {
      const content = await AdServer.fetch(id);
      this.cache.set(id, content);
    }));
  }
}

5.2 内存回收策略

// memory-manager.ets
class AdMemoryManager {
  private static readonly MAX_CACHE_SIZE = 5;

  static cleanup(): void {
    if (this.cache.size > this.MAX_CACHE_SIZE) {
      const keys = [...this.cache.keys()].slice(0, -this.MAX_CACHE_SIZE);
      keys.forEach(k => this.cache.delete(k));
    }
  }
}

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6. 完整组件集成

6.1 智能广告位组件

// smart-ad-slot.ets
@Component
struct SmartAdSlot {
  @State adContent?: AdContent;
  @State loading: boolean = false;

  build() {
    Column() {
      if (this.adContent) {
        AdaptiveAdContainer({ adContent: this.adContent })
      } else if (this.loading) {
        LoadingIndicator()
      } else {
        PlaceholderAd()
      }
    }
    .onAppear(() => this._loadAd())
  }

  private async _loadAd(): Promise<void> {
    this.loading = true;
    this.adContent = await AdLoader.fetch(this.adSlotId);
    this.loading = false;
  }
}

6.2 折叠动画过渡

// fold-transition.ets
@Component
struct FoldTransitionAd {
  @State private isFolded: boolean = false;

  build() {
    Stack() {
      // 背景层
      AdBackground()
      
      // 内容层
      AnimatedGroup()
        .onStateChange(this.isFolded ? 'folded' : 'expanded')
        .transition({
          duration: 300,
          curve: 'easeInOut'
        })
    }
    .onFoldStateChange((state) => {
      this.isFolded = state !== 'FULL';
    })
  }
}

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7. 生产环境配置

7.1 广告策略配置

// ad-policy.json
{
  "foldable": {
    "transitionDuration": 300,
    "breakpoints": {
      "folded": 600,
      "expanded": 1200
    },
    "density": {
      "folded": 1,
      "expanded": 3
    }
  }
}

7.2 尺寸映射配置

// size-mapper.ets
class AdSizeMapper {
  private static readonly SIZE_MAP = {
    folded: {
      banner: { width: 300, height: 100 },
      interstitial: { width: 280, height: 400 }
    },
    expanded: {
      banner: { width: 728, height: 90 },
      interstitial: { width: 600, height: 800 }
    }
  };

  static getSize(type: AdType, state: WindowFoldState): Size {
    return this.SIZE_MAP[state === 'FULL' ? 'expanded' : 'folded'][type];
  }
}

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8. 关键性能指标

场景	折叠状态	展开状态	优化目标
布局计算时间	<15ms	<25ms	95%达标
内存占用	≤8MB	≤15MB	100%达标
帧率稳定性	≥55 FPS	≥50 FPS	90%达标

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9. 扩展能力

9.1 动态广告密度调整

// density-adjuster.ets
class AdDensityAdjuster {
  static calculate(viewport: Size): number {
    const area = viewport.width * viewport.height;
    if (area > 1_000_000) return 3;
    if (area > 600_000) return 2;
    return 1;
  }
}

9.2 折叠敏感型动画

// fold-aware-animation.ets
class FoldAwareAnimator {
  static animate(element: Animatable, state: WindowFoldState): void {
    const params = state === 'FULL' ? 
      { duration: 500, curve: 'easeOut' } :
      { duration: 300, curve: 'easeIn' };
    
    element.animate({
      ...params,
      keyframes: this._getKeyframes(state)
    });
  }
}

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通过本方案可实现：

1. ​​无缝切换​​ 折叠/展开布局状态
2. ​​智能选择​​ 适配当前屏幕的广告素材
3. ​​高性能​​ 广告渲染（≥50 FPS）
4. ​​内存安全​​ 自动回收机制

完整广告组件集成：

ohpm install @harmony/ad-adaptive

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​​典型应用场景示例​​：

// 在折叠屏应用中使用广告组件
@Component
struct ShoppingApp {
  build() {
    Column() {
      ProductList()
      SmartAdSlot({
        slotId: 'home_bottom_banner',
        onAdClick: this._handleAdClick
      })
    }
  }
}