鸿蒙OS开发实例：【瀑布流式图片浏览】

介绍

瀑布流式展示图片文字，在当前产品设计中已非常常见，本篇将介绍关于WaterFlow的图片浏览场景，顺便集成Video控件，以提高实践的趣味性

准备

1. 请参照[官方指导]，创建一个Demo工程，选择Stage模型
2. 熟读HarmonyOS 官方指导“[https://gitee.com/li-shizhen-skin/harmony-os/blob/master/README.md”]

效果

竖屏

横屏

数据源

功能介绍

1. 瀑布流式图片展示
2. 横竖屏图片/视频展示

核心代码

布局

整体结构为：瀑布流 + 加载进度条

每条数据结构： 图片 + 文字 【由于没有设定图片宽高比，因此通过文字长度来自然生成瀑布流效果】

由于有点数据量，按照官方指导，采用LazyForEach懒加载方式

Stack() {
  WaterFlow({ scroller: this.scroller }) {
    LazyForEach(dataSource, item = > {
      FlowItem() {
        Column({ space: 10 }) {
          Image(item.coverUrl).objectFit(ImageFit.Cover)
            .width('100%')
            .height(this.imageHeight)
          Text(item.title)
            .fontSize(px2fp(50))
            .fontColor(Color.Black)
            .width('100%')
        }.onClick(() = > {
          router.pushUrl({ url: 'custompages/waterflow/Detail', params: item })
        })
      }
    }, item = > item)
  }
  .columnsTemplate(this.columnsTemplate)
  .columnsGap(5)
  .rowsGap(5)
  .onReachStart(() = > {
    console.info("onReachStart")
  })
  .onReachEnd(() = > {
    console.info("onReachEnd")

    if (!this.running) {
      if ((this.pageNo + 1) * 15 < this.total) {
        this.pageNo++
        this.running = true

        setTimeout(() = > {
          this.requestData()
        }, 2000)
      }
    }

  })
  .width('100%')
  .height('100%')
  .layoutDirection(FlexDirection.Column)

  if (this.running) {
     this.loadDataFooter()
  }

}
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横竖屏感知

横竖屏感知整体有两个场景：1. 当前页面发生变化 2.初次进入页面
这里介绍几种监听方式：

当前页面监听

import mediaquery from '@ohos.mediaquery';

//这里你也可以使用"orientation: portrait" 参数
listener = mediaquery.matchMediaSync('(orientation: landscape)');
this.listener.on('change', 回调方法)
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外部传参

通过UIAbility, 一直传到Page文件

事件传递

采用EeventHub机制，在UIAbility把横竖屏切换事件发出来，Page文件注册监听事件

this.context.eventHub.on('onConfigurationUpdate', (data) = > {
  console.log(JSON.stringify(data))
  let config = data as Configuration
  this.screenDirection = config.direction
  this.configureParamsByScreenDirection()
});
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API数据请求

这里需要设置Android 或者 iOS 特征UA

requestData() {
  let url = `https://api.apiopen.top/api/getHaoKanVideo?page=${this.pageNo}&size=15`
  let httpRequest = http.createHttp()
  httpRequest.request(
    url,
    {
      header: {
        "User-Agent": "Mozilla/5.0 (Linux; Android 8.0.0; SM-G955U Build/R16NW) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Mobile Safari/537.36"
      }
    }).then((value: http.HttpResponse) = > {

    if (value.responseCode == 200) {

      let searchResult: SearchResult = JSON.parse(value.result as string)

      if (searchResult) {
        this.total = searchResult.result.total

        searchResult.result.list.forEach(ItemModel = > {
          dataSource.addData(ItemModel)
        })
      }
    } else {
      console.error(JSON.stringify(value))
    }

  }).catch(e = > {

    Logger.d(JSON.stringify(e))

    promptAction.showToast({
      message: '网络异常: ' + JSON.stringify(e),
      duration: 2000
    })

  }).finally(() = > {
    this.running = false
  })

}
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横竖屏布局调整

因为要适应横竖屏，所以需要在原有布局的基础上做一点改造， 让瀑布流的列参数改造为@State 变量 ， 让图片高度的参数改造为@State 变量

WaterFlow({ scroller: this.scroller }) {
  LazyForEach(dataSource, item = > {
    FlowItem() {
      Column({ space: 10 }) {
        Image(item.coverUrl).objectFit(ImageFit.Cover)
          .width('100%')
          .height(this.imageHeight)
        Text(item.title)
          .fontSize(px2fp(50))
          .fontColor(Color.Black)
          .width('100%')
      }.onClick(() = > {
        router.pushUrl({ url: 'custompages/waterflow/Detail', params: item })
      })
    }
  }, item = > item)
}
.columnsTemplate(this.columnsTemplate)
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瀑布流完整代码

API返回的数据结构

import { ItemModel } from './ItemModel'

export default class SearchResult{
  public code: number
  public message: string
  public result: childResult
}

class childResult {
  public total: number
  public list: ItemModel[]
};
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Item Model

export class ItemModel{
  public id: number
  public tilte: string
  public userName: string
  public userPic: string
  public coverUrl: string
  public playUrl: string
  public duration: string
}复制

WaterFlow数据源接口

import List from '@ohos.util.List';
import { ItemModel } from './ItemModel';

export class PicData implements IDataSource {

  private data: List< ItemModel > = new List< ItemModel >()

  addData(item: ItemModel){
    this.data.add(item)
  }

  unregisterDataChangeListener(listener: DataChangeListener): void {

  }

  registerDataChangeListener(listener: DataChangeListener): void {

  }

  getData(index: number): ItemModel {
     return this.data.get(index)
  }

  totalCount(): number {
    return this.data.length
  }


}复制

布局

import http from '@ohos.net.http';
import { CommonConstants } from '../../common/CommonConstants';
import Logger from '../../common/Logger';
import { PicData } from './PicData';
import SearchResult from './Result';
import promptAction from '@ohos.promptAction'
import router from '@ohos.router';
import common from '@ohos.app.ability.common';
import { Configuration } from '@ohos.app.ability.Configuration';
import mediaquery from '@ohos.mediaquery';

let dataSource = new PicData()

/**
 * 问题： 横竖屏切换，间距会发生偶发性变化
 * 解决方案：延迟300毫秒改变参数
 *
 */
@Entry
@Component
struct GridLayoutIndex {
  private context = getContext(this) as common.UIAbilityContext;
  @State pageNo: number = 0
  total: number = 0
  @State running: boolean = true
  @State screenDirection: number = this.context.config.direction
  @State columnsTemplate: string = '1fr 1fr'
  @State imageHeight: string = '20%'
  scroller: Scroller = new Scroller()

  // 当设备横屏时条件成立
  listener = mediaquery.matchMediaSync('(orientation: landscape)');

  onPortrait(mediaQueryResult) {
    if (mediaQueryResult.matches) {
      //横屏
      this.screenDirection = 1
    } else {
      //竖屏
      this.screenDirection = 0
    }

    setTimeout(()= >{
      this.configureParamsByScreenDirection()
    }, 300)
  }

  onBackPress(){
    this.context.eventHub.off('onConfigurationUpdate')
  }

  aboutToAppear() {
    console.log('已进入瀑布流页面')

    console.log('当前屏幕方向：' + this.context.config.direction)

    if (AppStorage.Get('screenDirection') != 'undefined') {
      this.screenDirection = AppStorage.Get(CommonConstants.ScreenDirection)
    }

    this.configureParamsByScreenDirection()

    this.eventHubFunc()

    let portraitFunc = this.onPortrait.bind(this)
    this.listener.on('change', portraitFunc)

    this.requestData()
  }

  @Builder loadDataFooter() {
    LoadingProgress()
      .width(px2vp(150))
      .height(px2vp(150))
      .color(Color.Orange)
  }

  build() {
    Stack() {
      WaterFlow({ scroller: this.scroller }) {
        LazyForEach(dataSource, item = > {
          FlowItem() {
            Column({ space: 10 }) {
              Image(item.coverUrl).objectFit(ImageFit.Cover)
                .width('100%')
                .height(this.imageHeight)
              Text(item.title)
                .fontSize(px2fp(50))
                .fontColor(Color.Black)
                .width('100%')
            }.onClick(() = > {
              router.pushUrl({ url: 'custompages/waterflow/Detail', params: item })
            })
          }
        }, item = > item)
      }
      .columnsTemplate(this.columnsTemplate)
      .columnsGap(5)
      .rowsGap(5)
      .onReachStart(() = > {
        console.info("onReachStart")
      })
      .onReachEnd(() = > {
        console.info("onReachEnd")

        if (!this.running) {
          if ((this.pageNo + 1) * 15 < this.total) {
            this.pageNo++
            this.running = true

            setTimeout(() = > {
              this.requestData()
            }, 2000)
          }
        }

      })
      .width('100%')
      .height('100%')
      .layoutDirection(FlexDirection.Column)

      if (this.running) {
         this.loadDataFooter()
      }

    }

  }

  requestData() {
    let url = `https://api.apiopen.top/api/getHaoKanVideo?page=${this.pageNo}&size=15`
    let httpRequest = http.createHttp()
    httpRequest.request(
      url,
      {
        header: {
          "User-Agent": "Mozilla/5.0 (Linux; Android 8.0.0; SM-G955U Build/R16NW) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/116.0.0.0 Mobile Safari/537.36"
        }
      }).then((value: http.HttpResponse) = > {

      if (value.responseCode == 200) {

        let searchResult: SearchResult = JSON.parse(value.result as string)

        if (searchResult) {
          this.total = searchResult.result.total

          searchResult.result.list.forEach(ItemModel = > {
            dataSource.addData(ItemModel)
          })
        }
      } else {
        console.error(JSON.stringify(value))
      }

    }).catch(e = > {

      Logger.d(JSON.stringify(e))

      promptAction.showToast({
        message: '网络异常: ' + JSON.stringify(e),
        duration: 2000
      })

    }).finally(() = > {
      this.running = false
    })

  }

  eventHubFunc() {
    this.context.eventHub.on('onConfigurationUpdate', (data) = > {
      console.log(JSON.stringify(data))
      // let config = data as Configuration
      // this.screenDirection = config.direction
      // this.configureParamsByScreenDirection()
    });
  }

  configureParamsByScreenDirection(){
    if (this.screenDirection == 0) {
      this.columnsTemplate = '1fr 1fr'
      this.imageHeight = '20%'
    } else {
      this.columnsTemplate = '1fr 1fr 1fr 1fr'
      this.imageHeight = '50%'
    }
  }

}

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图片详情页

import { CommonConstants } from '../../common/CommonConstants';
import router from '@ohos.router';
import { ItemModel } from './ItemModel';
import common from '@ohos.app.ability.common';
import { Configuration } from '@ohos.app.ability.Configuration';

@Entry
@Component
struct DetailIndex{
  private context = getContext(this) as common.UIAbilityContext;

  extParams: ItemModel
  @State previewUri: Resource = $r('app.media.splash')
  @State curRate: PlaybackSpeed = PlaybackSpeed.Speed_Forward_1_00_X
  @State isAutoPlay: boolean = false
  @State showControls: boolean = true
  controller: VideoController = new VideoController()

  @State screenDirection: number = 0
  @State videoWidth: string = '100%'
  @State videoHeight: string = '70%'

  @State tipWidth: string = '100%'
  @State tipHeight: string = '30%'

  @State componentDirection: number = FlexDirection.Column
  @State tipDirection: number = FlexDirection.Column

  aboutToAppear() {
    console.log('准备加载数据')
    if(AppStorage.Get('screenDirection') != 'undefined'){
      this.screenDirection = AppStorage.Get(CommonConstants.ScreenDirection)
    }

    this.configureParamsByScreenDirection()

    this.extParams = router.getParams() as ItemModel
    this.eventHubFunc()
  }

  onBackPress(){
    this.context.eventHub.off('onConfigurationUpdate')
  }

  build() {
      Flex({direction: this.componentDirection}){
        Video({
          src: this.extParams.playUrl,
          previewUri: this.extParams.coverUrl,
          currentProgressRate: this.curRate,
          controller: this.controller,
        }).width(this.videoWidth).height(this.videoHeight)
          .autoPlay(this.isAutoPlay)
          .objectFit(ImageFit.Contain)
          .controls(this.showControls)
          .onStart(() = > {
            console.info('onStart')
          })
          .onPause(() = > {
            console.info('onPause')
          })
          .onFinish(() = > {
            console.info('onFinish')
          })
          .onError(() = > {
            console.info('onError')
          })
          .onPrepared((e) = > {
            console.info('onPrepared is ' + e.duration)
          })
          .onSeeking((e) = > {
            console.info('onSeeking is ' + e.time)
          })
          .onSeeked((e) = > {
            console.info('onSeeked is ' + e.time)
          })
          .onUpdate((e) = > {
            console.info('onUpdate is ' + e.time)
          })

        Flex({direction: this.tipDirection, justifyContent: FlexAlign.Center, alignItems: ItemAlign.Center, alignContent: FlexAlign.Center}){
          Row() {
            Button('src').onClick(() = > {
              // this.videoSrc = $rawfile('video2.mp4') // 切换视频源
            }).margin(5)
            Button('previewUri').onClick(() = > {
              // this.previewUri = $r('app.media.poster2') // 切换视频预览海报
            }).margin(5)
            Button('controls').onClick(() = > {
              this.showControls = !this.showControls // 切换是否显示视频控制栏
            }).margin(5)
          }

          Row() {
            Button('start').onClick(() = > {
              this.controller.start() // 开始播放
            }).margin(5)
            Button('pause').onClick(() = > {
              this.controller.pause() // 暂停播放
            }).margin(5)
            Button('stop').onClick(() = > {
              this.controller.stop() // 结束播放
            }).margin(5)
            Button('setTime').onClick(() = > {
              this.controller.setCurrentTime(10, SeekMode.Accurate) // 精准跳转到视频的10s位置
            }).margin(5)
          }
          Row() {
            Button('rate 0.75').onClick(() = > {
              this.curRate = PlaybackSpeed.Speed_Forward_0_75_X // 0.75倍速播放
            }).margin(5)
            Button('rate 1').onClick(() = > {
              this.curRate = PlaybackSpeed.Speed_Forward_1_00_X // 原倍速播放
            }).margin(5)
            Button('rate 2').onClick(() = > {
              this.curRate = PlaybackSpeed.Speed_Forward_2_00_X // 2倍速播放
            }).margin(5)
          }
        }
        .width(this.tipWidth).height(this.tipHeight)
      }

  }

  eventHubFunc() {
    this.context.eventHub.on('onConfigurationUpdate', (data) = > {
       console.log(JSON.stringify(data))
       let config = data as Configuration
       this.screenDirection = config.direction

       this.configureParamsByScreenDirection()

    });
  }


  configureParamsByScreenDirection(){
    if(this.screenDirection == 0){
      this.videoWidth = '100%'
      this.videoHeight = '70%'
      this.tipWidth = '100%'
      this.tipHeight = '30%'
      this.componentDirection = FlexDirection.Column

    } else {
      this.videoWidth = '60%'
      this.videoHeight = '100%'
      this.tipWidth = '40%'
      this.tipHeight = '100%'
      this.componentDirection = FlexDirection.Row

    }

  }

}

审核编辑 黄宇