RecyclerView 选择从 LiveData 观察加载的项目

Question

我的 ViewModel 中有一个 LiveData，它是从 Room 数据库加载的，经过转换后，我将其显示在 RecyclerView 中。我想要的是具有选择功能。

ShareViewModel 类

val serverConnections: LiveData<List<ShareConnectionModelUi>> = 
    Transformations.map(shareManager.serverWithAccounts) {
        // Here **it**, which is a Map<Server, List<Account>> gets transformed into a list
        // of ShareConnectionModelUi

        // e.g. Map of 
        // Server1, [Account1, Account11]
        // Server2, [Account2, Account22]
        // will be transformed to 
        // [Server1, Account1, Account11, Server2, Account2, Account22 ...]
    }


// The UiModel
sealed class ShareConnectionModelUi {
    class ServerItem(val server: Server): ShareConnectionModelUi()
    class ConnectionItem(val connectionItem: Account, var checked: Boolean): ShareConnectionModelUi()
}

在 Fragment 中，我观察 LiveData 并将其传递给 RecyclerAdapter，后者通过 ViewType 呈现相对布局。因此，当布局为 ShareConnectionModelUi.ConnectionItem 时，我希望用户能够通过单击来选中或取消选中该项目。我使用 ConnectionItem 布局的接口。但是，我如何更新 LiveData 以便将 checkImage 显示到 ConnectionItemLayout，因为 checkImg 的可见性是通过 ShareConnectionModelUI.ConnectionItem.check 实现的？

我想我必须更新 LiveData。这是Viewmodel内部的试用功能，它不起作用......

fun selectConnection(account: Account) {
        serverConnections.value?.let {
            it.find { s ->
                s is ShareConnectionModelUi.ConnectionItem
                        && s.connectionItem.serverId == account.serverId
                        && s.connectionItem.accountId == account.accountId
            }?.let { s ->
                (s as ShareConnectionModelUi.ConnectionItem).checked == checked
            }
        }
    }

Answer 1

此比较的结果未使用：

(s as ShareConnectionModelUi.ConnectionItem).checked == checked

这应该是一个赋值吗？

(s as ShareConnectionModelUi.ConnectionItem).checked = checked