jetpack Compose 学习笔记

目录

Modifier.clickable() 取消点击水波纹

LazyColum 相关

Modifier.clickable() 取消点击水波纹

		modifier = Modifier
            .clickable(onClick = {}, indication = null, interactionSource = remember {
                MutableInteractionSource()
            })

LazyColum 相关

根据List.size设置内容，并提item的内容和position

LazyColumn {
            itemsIndexed(viewState.localList) { position, local ->
                LocalMusicItem(local, position) {
                    Log.d("TAG", "LocalScreen: $it")
                }
            }
        }

LazyColum 取消overscroll效果（光晕）

CompositionLocalProvider(
    LocalOverScrollConfiguration provides null //禁用
) {
    LazyColumn() {
        items() {
            
        }
    }
}

 LazyColum 更新某项item State

//在ViewModel中

data class ItemState(
    val selected: Boolean
    val dataBean: DataBean
)

class ViewModel: ViewModel() {
    val listState = mutableStateListOf<ItemState>()

    fun selected(position: Int, isSelected: Boolean) {
        items[position] = items[position].copy(
            selected = isSelected
        )
    }
}

//在Compose中
val listState = viewModel.listState

LazyColumn {
    //更新指定的某一项需要position索引，所以用itemsIndexed
    itemsIndexed(listState) { position, itemState -> 
        item(
            dataBean = itemState.dataBean,
            isSelected = itemState.selected
            onItemSelect = { pos, bean ->
                viewModel.selected(pos, !itemState.selected)
            }
        )
    }
}

如果要实现只有一项item选中效果，我目前使用的方法是

用一个int值保存上一个选中的item，点击的时候取消上一个item的选中状态，再把上一个选中item的值替换为当前item 的 position 

贴张效果图 

获取屏幕宽高

    val configuration = LocalConfiguration.current

    val screenHeightDp = configuration.screenHeightDp.dp
    
    val screenHeightPx = with(LocalDensity.current) {
        screenHeightDp.toPx()
    }