Android 使用 List 和 LazyColumn 重新组合所有项目

如果将List<Interface>与LazyColumn一起使用，则会重新组合所有项，而如果我使用List<Implementation>，则它会智能地跳过重新组合.

例如，如果我在可组合重组中使用示例1 MutableList，则对列表中的所有加法操作的项进行重组，但在示例2中，它会智能地跳过.WHY?

例1:

    val selectionState: MutableList<ViewItemScratch> = remember {
      mutableStateListOf()
    }

示例2:

    val selectionState: MutableList<TitleViewItemScratch> = remember {
      mutableStateListOf()
    }

接口:

interface ViewItemScratch {
  val identifier: Int
  val layoutId: Int

  @SuppressLint("NotConstructor")
  @Composable
  fun ViewItem(
    lazyItemScope: LazyItemScope? = null,
    rowScope: RowScope? = null,
    columnScope: ColumnScope? = null
  ) {
  }
}

实施类:

data class TitleViewItemScratch(
  val index: Int,
  val text: StringResolver,
  val modifier: Modifier = Modifier,
  override val identifier: Int = text.hashCode()
) : ViewItemScratch {
  override val layoutId: Int
    get() = R.id.compose_view_title_view_item

  @Composable
  override fun ViewItem(
    lazyItemScope: LazyItemScope?, rowScope: RowScope?, columnScope: ColumnScope?
  ) {
    Text(
      modifier = modifier
        .fillMaxWidth()
        .wrapContentHeight()
        .padding(horizontal = 16.dp),
      text = text.resolve(),
    )
  }
}

可组合的:

 @Composable
  private fun WithViewItemScratch() {
    val selectionState: MutableList<ViewItemScratch> = remember {
      mutableStateListOf()
    }
    val onButtonClick = remember {
      {
        selectionState.add(
          TitleViewItemScratch(
            index = selectionState.size + 1,
            text = UIString("Hello world #${selectionState.size + 1}"),
            identifier = selectionState.size + 1,
          )
        )
      }
    }
    Column {
      Button(onClick = {
        onButtonClick.invoke()
      }) {
        Text(text = "Add")
      }
      LazyColumn {
        items(
          items = selectionState,
          key = { viewItem: ViewItemScratch -> viewItem.identifier }
        ) { item ->
          item.ViewItem()
        }
      }
    }
  }

编译报道(S):

restartable skippable fun ViewItem(
  unused stable lazyItemScope: LazyItemScope? = @static null
  unused stable rowScope: RowScope? = @static null
  unused stable columnScope: ColumnScope? = @static null
  unused <this>: ViewItemScratch
)

stable class TitleViewItemScratch {
  stable val index: Int
  stable val text: StringResolver
  stable val color: CompassColor
  stable val typography: CompassTypography
  stable val modifier: Modifier
  stable val identifier: Int
  <runtime stability> = Stable
}

版面判断器重新组合:

With List of 接口:

带实现列表/具体类: