添加到可变列表（NPE）Kotlin Android时出错

Question

-数据类-]

试图向进餐添加对象MutableList

data class YelpRestaurant(

val name: String,
val rating: Double,
val price: String,
@SerializedName("review_count") val numReviews: Int,
@SerializedName("image_url") val imageUrl: String,
val categories: List<YelpCategory>,
val location: YelpLocation,
val meals: MutableList<UserMeals>
）

-我的活动---

class ThoughtsActivity : AppCompatActivity() {

lateinit var mealName: String
lateinit var mealPrice: String
lateinit var mealThought: String

lateinit var selected_Restaurant : YelpRestaurant

@Subscribe(sticky = true)
fun getRest(selectedRestaurant : YelpRestaurant)  {
    selected_Restaurant = selectedRestaurant

}

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_thoughts)

    thoughtBtn.setOnClickListener() {

        mealName = m_name.text.toString()
        mealPrice = m_price.text.toString()
        mealThought = m_thought.text.toString()

        var addedMeal = UserMeals(mealName, mealPrice.toDouble(), mealThought)

        if (mealName.isNotEmpty()) {
            selected_Restaurant.meals.add(0,addedMeal)
^^^ java.lang.NullPointerException：尝试在空对象引用上调用接口方法'void java.util.List.add（int，java.lang.Object）'。

Debugger where meals=null

   Log.i(selected_Restaurant.meals[0].mealName,"UserMeal Added")
        }
    }
}

override fun onStart() {
    super.onStart()
    EventBus.getDefault().register(this)
}

override fun onStop() {
    super.onStop()
    EventBus.getDefault().unregister(this)
}
}

-数据类---尝试向餐中添加对象MutableList数据类YelpRestaurant（val名称：String，val等级：Double，val价格：字符串，@SerializedName（“ review_count”）val numReviews：整数，@。 ..

Answer 1

将meals更改为val，并在selected_Restaurant中这样声明时实例化它：