向 HashMap 添加新元素但查询时未找到 - Kotlin

Question

我正在尝试根据键值向HashMap 添加新的列表元素，其值为嵌套列表。

这是我初始化的类：

private val portalDummyData = listOf(
Portal(
  id = "p1", address = "Moringa", clientID = "c1", clientSecret = "cs1", agents = mutableListOf(
    Agent(
      "agent1", "agent", email, listOf(
        "p1"
      )
    ),
    Agent(
      "agent2", "agent2", email, listOf(
        "p1", "p2"
      )
    )
  )
 )
)
private val portalHashMap = HashMap<String, Portal>()

init {
  portalDummyData.forEach { portalHashMap[it.id] = it }
}

您可以看到portalHashMap 的每个值我存储为列表，并且该列表中包含另一个列表。所以，我想将新的列表元素添加到保留在其父列表中的列表中。但是当我添加新元素并且找不到该元素时。

这是我尝试添加新列表元素的代码：

override suspend fun addAgentToPortal(agent: Agent, id: String) {
val portal = portalHashMap[id]
if (portal != null) {
  val agents = portal.agents
  agents.toMutableList().add(agent)
  print(agents.count())
} else {
  throw NotFoundException("Portal not found")
}
}

我想将新的Agent 模型添加到那个Portal 模型但是当我println(agents.count()) 但值仍然与默认值相同。

Answer 1

使用可变列表而不是列表。您不能在 List 中添加新元素

Portal(
        id = "p1", address = "Moringa", clientID = "c1", clientSecret = "cs1", 
        agents = mutableListOf(
            Agent( "agent1", "agent", email, listOf("p1")),
            Agent("agent2", "agent2", email, listOf("p1", "p2"))
        )
    )