图片九宫格封装案例

aboutToAppear(){
  this.arraySize = this.imageSource.length
  // 未传入col值时所走的逻辑，此时图片按默认方式布局
  if (this.col <= COLUMNS_0) {
    this.arraySize = Math.min(this.imageSource.length, IMAGE_SET_SIZE_9)
    this.row = Math.ceil(this.arraySize / COLUMNS_3)

    // 不同数量的图片对应不同的参数、布局
    if (this.arraySize === IMAGE_SET_SIZE_1) {
      this.col = COLUMNS_1
      this.imageAspectRatio = IMAGE_ASPECT_RATIO_0
      this.imageFit = ImageFit.Contain
      this.imageWidth = '60%'
    }
    else if (this.arraySize === IMAGE_SET_SIZE_4) {
      this.col = COLUMNS_2
      this.flexWidth = '50%'
      this.imageWidth = `calc((100% - ${this.imageSpacing}vp ) / 2)`
    }
    else {
      this.col = COLUMNS_3
      this.imageWidth = `calc((100% - ${this.imageSpacing * COLUMNS_2}vp ) / 3)`
    }
  }
  // 传入col值时所走的逻辑，此时图片传入的col值进行布局
  else {
    this.row = Math.ceil(this.arraySize / this.col)
    this.imageWidth = `calc((100% - ${this.imageSpacing * (this.col - 1)}vp ) / ${this.col})`
  }

}

build(){
  Flex({ wrap: FlexWrap.Wrap, justifyContent: FlexAlign.Start }){
    ForEach(this.imageSource.slice(0, this.arraySize), (item: string | Resource, idx: number) => {
      Image(item)
        .attributeModifier(this.modifier)
        .autoResize(true)
        .objectFit(this.imageFit)
        .aspectRatio(this.imageAspectRatio)
        .width(this.imageWidth)
        .margin(
          {
            bottom: (idx + 1) > ((this.row - 1) * this.col) ? 0 : this.imageSpacing,
            right: (idx + 1) % this.col === 0 ? 0 : this.imageSpacing
          }
        )
    })
  }
  .width(this.flexWidth)
}

// 图片属性的modifier类，便于用户扩展image相关的属性
class ImageModifier implements AttributeModifier<ImageAttribute> {
  private imageFit: ImageFit = ImageFit.Fill;
  private imageRenderMode: ImageRenderMode = ImageRenderMode.Original;

  constructor() {
  }

  applyNormalAttribute(instance: ImageAttribute): void {
    instance.objectFit(this.imageFit)
    instance.renderMode(this.imageRenderMode)
  }

  objectFit(fit: ImageFit): ImageModifier {
    this.imageFit = fit;
    return this;
  }

  renderMode(mode: ImageRenderMode): ImageModifier {
    this.imageRenderMode = mode;
    return this;
  }
}
···
private imageModifier: ImageModifier = new ImageModifier().objectFit(ImageFit.Fill)
  .renderMode(ImageRenderMode.Original)
···
MultiGrid({ imageSource: item, modifier: this.imageModifier })

imagegridlayout                             // har类型
|---src/main/ets/components/mainpage
|   |---ImageGridLayout.ets                 // 图片九宫格展示实现页面
|   |---MultiGrid.ets                       // 图片九宫格案例封装