尝试在意图 Kotlin 中传递 Parcelable 时对空对象引用调用接口方法'int java.util.List.size()'

Question

因此，我有一个示例应用程序，该应用程序当前正在使用改装来获取数据，并将其显示在带有自定义适配器的回收视图中。当我点击recyclerView上的字符名称时，我想将数据传递到更多详细信息页面。我找到了一些教程，并决定使用Parcelize注释，如下所示：

@Parcelize data class Character (
val charID: Long,
val name: String,
val birthday: String,
val occupation: List<String>,
val img: String,
val status: String,
val nickname: String,
val appearance: List<Long>,
val portrayed: String,
val category: String,
val betterCallSaulAppearance: List<Long> ) : Parcelable

我的适配器看起来是这样的：

override fun onBindViewHolder(holder: ViewHolder, position: Int) {
val character = characters[position]
holder.characterNameText.text = character.name
holder.characterNameText.setOnClickListener {
holder.passData(character)
}
}
override fun getItemCount() = characters.size

class ViewHolder(itemView : View) : RecyclerView.ViewHolder(itemView) {
val characterNameText = itemView.findViewById<TextView>(R.id.character_name)
fun passData(character : Character) {
val intent = Intent(itemView.context, CharacterDetails::class.java)
intent.putExtra(CHARACTER, character)
itemView.context.startActivity(intent)
}

}

在CharacterDetails活动中，它看起来像这样：

companion object {
const val CHARACTER = "character"
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_character_details)
val bundle = intent.extras
val character = bundle!!.getParcelable<Character>(CHARACTER)

val characterName = findViewById<TextView>(R.id.character_details_name)

然而我得到了

java.lang.NullPointerException：尝试在null对象引用上调用接口方法"int java.util.List.size(("网址：com.example.mapplication.models.Character.writeToParcel(未知来源：85(

我还是新手，所以我真的需要你的帮助。谢谢

Answer 1

显然，数据类的列表引用导致的错误为null。您可以这样修改代码。

@Parcelize data class Character (
val charID: Long,
val name: String,
val birthday: String,
val occupation: List<String>?,
val img: String,
val status: String,
val nickname: String,
val appearance: List<Long>?,
val portrayed: String,
val category: String,
val betterCallSaulAppearance: List<Long>? ) : Parcelable