Image($r('app.media.app_icon'))
  .draggable(true)  // 1. 使能拖拽
  .onDragStart((event) => {
    // 2. 设置拖拽数据
    let data = new unifiedDataChannel.Image();
    data.imageUri = '资源路径';
    let unifiedData = new unifiedDataChannel.UnifiedData(data);
    event.setData(unifiedData);
    
    // 3. 返回自定义背板图
    return {
      pixelMap: this.pixmap,
      extraInfo: "额外信息"
    };
  })

.parallelGesture(LongPressGesture().onAction(() => {
  // 并行手势，不干扰拖拽
}))

.onPreDrag((status: PreDragStatus) => {
  if (status == PreDragStatus.ACTION_DETECTING_STATUS) {
    this.getComponentSnapshot(); // 提前生成截图
  }
})

private getComponentSnapshot(): void {
  this.getUIContext().getComponentSnapshot().createFromBuilder(
    () => { this.pixelMapBuilder() },
    (error, pixmap) => {
      this.pixmap = pixmap;
    }
  );
}

// 在 Ability 中设置
uiContext.getDragController().setDragEventStrictReportingEnabled(true);

.allowDrop([
  uniformTypeDescriptor.UniformDataType.HYPERLINK,
  uniformTypeDescriptor.UniformDataType.PLAIN_TEXT
])

.onDragMove((event) => {
  event.setResult(DragResult.DROP_ENABLED);
  event.dragBehavior = DragBehavior.COPY; // 显示加号
  // 或 DragBehavior.MOVE; // 不显示加号
})

.onDrop((dragEvent?: DragEvent) => {
  this.getDataFromUdmf(dragEvent as DragEvent, (event: DragEvent) => {
    // 1. 获取数据
    let records = event.getData().getRecords();
    
    // 2. 处理数据
    this.targetImage = (records[0] as Image).imageUri;
    
    // 3. 必须显式设置结果
    event.setResult(DragResult.DRAG_SUCCESSFUL);
  });
})

.onDragEnd((event) => {
  if (event.getResult() === DragResult.DRAG_SUCCESSFUL) {
    // 成功处理
  } else if (event.getResult() === DragResult.DRAG_FAILED) {
    // 失败处理
  }
})

.dragPreviewOptions({
  isMultiSelectionEnabled: true,  // 启用多选
  defaultAnimationBeforeLifting: true  // 浮起前显示缩小动画
})

GridItem()
  .selectable(true)
  .selected(this.isSelectedGrid[idx])  // 设置选中状态
  .onClick(() => {
    this.isSelectedGrid[idx] = !this.isSelectedGrid[idx]; // 切换选中
  })

@Styles normalStyles() { .opacity(1.0) }
@Styles selectStyles() { .opacity(0.4) }

.stateStyles({
  normal: this.normalStyles,
  selected: this.selectStyles
})

@State numberBadge: number = 0;

.onClick(() => {
  this.isSelectedGrid[idx] = !this.isSelectedGrid[idx];
  if (this.isSelectedGrid[idx]) {
    this.numberBadge++;
  } else {
    this.numberBadge--;
  }
})

.dragPreviewOptions({ numberBadge: this.numberBadge }, 
  { isMultiSelectionEnabled: true })

.onDrop((dragEvent: DragEvent) => {
  dragEvent.useCustomDropAnimation = true;  // 禁用系统默认动效
  dragEvent.executeDropAnimation(this.customDropAnimation);  // 执行自定义动效
})

customDropAnimation = () => {
  this.getUIContext().animateTo(
    { duration: 1000, curve: Curve.EaseOut, playMode: PlayMode.Normal },
    () => {
      this.imageWidth = 200;  // 改变大小
      this.imageHeight = 200;
      this.imgState = Visibility.None;
    }
  );
}

draggable(true)
  ↓
onPreDrag（可选，提前准备）
  ↓
onDragStart（设置数据+背板图）
  ↓
onDragEnd（接收结果）

allowDrop（设置接受的数据类型）
  ↓
onDragEnter/Move/Leave（可选，UI反馈）
  ↓
onDrop（必须，处理数据+设置结果）
  ↓
onDragSpringLoading（可选，悬停检测）

selectable(true) + selected()
  ↓
dragPreviewOptions(isMultiSelectionEnabled: true)
  ↓
选中时逐步添加数据
  ↓
onDragStart（处理多选数据）