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HarmonyOS NEXT系列教程之列表交换组件实战应用案例

效果演示

1. 银行卡管理场景

1.1 基础实现

@Component
struct BankCardManager {
    @State cardList: BankCard[] = [];
    private cardController: ListExchangeCtrl<BankCard> = new ListExchangeCtrl();

    build() {
        Column() {
            ListExchange({
                items: this.cardList,
                listExchangeCtrl: this.cardController,
                deductionView: this.cardItemBuilder
            })
        }
    }

    @Builder
    cardItemBuilder(card: BankCard) {
        Row() {
            Image(card.bankIcon)
                .width(40)
                .height(40)
            Column() {
                Text(card.bankName)
                    .fontSize(16)
                Text(card.cardNumber)
                    .fontSize(14)
                    .opacity(0.6)
            }
            .margin({ left: 12 })
        }
        .width('100%')
        .padding(16)
    }
}

1.2 数据模型

class BankCard {
    id: string;
    bankName: string;
    cardNumber: string;
    bankIcon: Resource;
    isDefault: boolean;

    constructor(data: Partial<BankCard>) {
        Object.assign(this, data);
    }
}

2. 待办事项列表

2.1 组件实现

@Component
struct TodoList {
    @State todoItems: TodoItem[] = [];
    private todoController: ListExchangeCtrl<TodoItem> = new ListExchangeCtrl();

    build() {
        Column() {
            ListExchange({
                items: this.todoItems,
                listExchangeCtrl: this.todoController,
                deductionView: this.todoItemBuilder
            })
            .onItemDelete((item: TodoItem) => {
                this.handleDelete(item);
            })
            .onItemMove((from: number, to: number) => {
                this.handlePriorityChange(from, to);
            })
        }
    }

    @Builder
    todoItemBuilder(item: TodoItem) {
        Row() {
            Checkbox()
                .select(item.completed)
                .onChange((value: boolean) => {
                    this.toggleComplete(item, value);
                })
            Text(item.title)
                .decoration({ type: item.completed ? 
                    TextDecorationType.LineThrough : 
                    TextDecorationType.None 
                })
            Text(item.dueDate)
                .fontSize(12)
        }
        .width('100%')
        .padding(16)
    }
}

2.2 业务逻辑

class TodoManager {
    // 切换完成状态
    toggleComplete(item: TodoItem, completed: boolean) {
        item.completed = completed;
        this.updateItem(item);
    }

    // 处理优先级变更
    handlePriorityChange(fromIndex: number, toIndex: number) {
        const priority = this.calculatePriority(toIndex);
        this.todoItems[fromIndex].priority = priority;
        this.sortItems();
    }

    // 计算优先级
    private calculatePriority(index: number): number {
        const step = 100;
        return (index + 1) * step;
    }
}

3. 音乐播放列表

3.1 组件实现

@Component
struct MusicPlaylist {
    @State tracks: MusicTrack[] = [];
    private playlistController: ListExchangeCtrl<MusicTrack> = new ListExchangeCtrl();

    build() {
        Column() {
            ListExchange({
                items: this.tracks,
                listExchangeCtrl: this.playlistController,
                deductionView: this.trackItemBuilder
            })
            .onItemMove((from: number, to: number) => {
                this.updatePlayOrder(from, to);
            })
        }
    }

    @Builder
    trackItemBuilder(track: MusicTrack) {
        Row() {
            Image(track.albumCover)
                .width(50)
                .height(50)
                .borderRadius(8)
            Column() {
                Text(track.title)
                    .fontSize(16)
                Text(`${track.artist} · ${track.album}`)
                    .fontSize(14)
                    .opacity(0.6)
            }
            .margin({ left: 12 })
            Image($r('app.media.ic_play'))
                .width(24)
                .height(24)
                .onClick(() => this.playTrack(track))
        }
        .width('100%')
        .padding(16)
    }
}

3.2 播放控制

class PlaylistController {
    private audioPlayer: AudioPlayer = new AudioPlayer();

    // 播放音乐
    async playTrack(track: MusicTrack) {
        await this.audioPlayer.stop();
        await this.audioPlayer.src(track.url);
        await this.audioPlayer.play();
    }

    // 更新播放顺序
    updatePlayOrder(fromIndex: number, toIndex: number) {
        this.savePlaylistOrder();
        this.updateNowPlaying();
    }
}

4. 照片相册管理

4.1 组件实现

@Component
struct PhotoAlbum {
    @State photos: PhotoItem[] = [];
    private albumController: ListExchangeCtrl<PhotoItem> = new ListExchangeCtrl();

    build() {
        Column() {
            ListExchange({
                items: this.photos,
                listExchangeCtrl: this.albumController,
                deductionView: this.photoItemBuilder
            })
            .onItemDelete((item: PhotoItem) => {
                this.deletePhoto(item);
            })
        }
    }

    @Builder
    photoItemBuilder(photo: PhotoItem) {
        Stack() {
            Image(photo.url)
                .width('100%')
                .height(200)
                .objectFit(ImageFit.Cover)
            Column() {
                Text(photo.date)
                Text(photo.location)
            }
            .position({ x: 8, y: 8 })
        }
        .width('100%')
    }
}

4.2 图片处理

class PhotoManager {
    // 删除照片
    async deletePhoto(photo: PhotoItem) {
        try {
            await this.deleteFromStorage(photo);
            await this.removeFromAlbum(photo);
            this.updateThumbnails();
        } catch (error) {
            console.error('Failed to delete photo:', error);
        }
    }

    // 优化图片加载
    private optimizeImage(url: string): Promise<string> {
        return ImageOptimizer.process(url, {
            maxWidth: 800,
            quality: 0.8,
            format: 'webp'
        });
    }
}

5. 性能优化实践

5.1 图片优化

class ImageOptimizer {
    private static cache: Map<string, string> = new Map();

    static async loadOptimized(url: string): Promise<string> {
        if (this.cache.has(url)) {
            return this.cache.get(url);
        }

        const optimized = await this.processImage(url);
        this.cache.set(url, optimized);
        return optimized;
    }

    static clearCache() {
        this.cache.clear();
    }
}

5.2 列表优化

// 虚拟列表优化
@Component
struct OptimizedList {
    private virtualListController: VirtualListController = new VirtualListController();

    build() {
        List() {
            LazyForEach(this.virtualListController, (item: any) => {
                ListItem() {
                    this.itemBuilder(item)
                }
            })
        }
        .onScrollIndex((first: number) => {
            this.virtualListController.loadMore(first);
        })
    }
}

6. 最佳实践总结

6.1 实现建议

1. 根据业务场景选择合适的交互方式
2. 优化图片和资源加载
3. 实现错误处理和恢复机制
4. 提供良好的用户反馈

6.2 性能建议

1. 使用虚拟列表处理大量数据
2. 实现图片懒加载和缓存
3. 优化动画和交互效果
4. 合理管理内存资源

7. 小结

本篇教程详细介绍了：

1. 银行卡管理的实现方案
2. 待办事项列表的开发方法
3. 音乐播放列表的实现细节
4. 照片相册的优化策略
5. 实际应用中的最佳实践

这些实战案例将帮助你更好地理解和使用ListExchange组件。