Question

我有一个包含RecyclerAdapter的片段。我想在onCreateView方法中初始化适配器，但它会在此语句中抛出"Type mismatch. Required : Context , Found : FragmentActivity"的错误

我不知道为什么第一个显示此错误而第二个不包含编译时错误。

显示错误

recyclerView!!.adapter = RestaurantMenuAdapter(activity)

未显示错误

recyclerView!!.layoutManager = LinearLayoutManager(activity)

Fragment.kt

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                          savedInstanceState: Bundle?): View? {
    // Inflate the layout for this fragment
    val view = inflater.inflate(R.layout.fragment_restaurant_menu, container, false)
    recyclerView = view.findViewById(R.id.restaurant_container)
    recyclerView!!.adapter = RestaurantMenuAdapter(activity)
    recyclerView!!.layoutManager = LinearLayoutManager(activity)

RecyclerAdapter.kt

class RestaurantMenuAdapter  (val context : Context) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        val inflater = parent.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        return object : RecyclerView.ViewHolder(inflater.inflate(R.layout.item_menu1, parent, false)) {

        }
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {

    }

    override fun getItemCount(): Int {
        return 10
    }
}

Answer 1

将此更改为 - ：

recyclerView!!.adapter = RestaurantMenuAdapter(activity)

要 - ：

recyclerView!!.adapter = RestaurantMenuAdapter(activity.applicationContext)

Answer 2

recyclerView!!.adapter = RestaurantMenuAdapter(this)

收件人

recyclerView!!.adapter = RestaurantMenuAdapter(this.requireActivity())

Answer 3

更换Recycler适配器从上下文到活动。

class RestaurantMenuAdapter  (val context : Activity) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        val inflater = parent.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
        return object : RecyclerView.ViewHolder(inflater.inflate(R.layout.item_menu1, parent, false)) {

        }
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {

    }

    override fun getItemCount(): Int {
        return 10
    }
}

Answer 4

保持适配器不变，只需使用“活动！！”在哪里初始化适配器。

protected static $serialize = true;

您的适配器将保持不变。

recyclerView.adapter = RestaurantMenuAdapter(activity!!)

Kotlin显示片段中的类型不匹配

4 个答案: