Question

我在Android Studio中收到以下警告：＆＃34;来自视图适配器的无条件布局膨胀：应使用View Holder模式（使用传递给此方法的循环视图作为第二个参数）以实现更顺畅的滚动。＆＃34;在inflater.inflate（R.layout.animal_ticket，null）行。

如何修复警告？我无法找到解决该问题的方法。

谢谢！

override fun getView(p0: Int, p1: View?, p2: ViewGroup?): View {
        val animal = listOfAnimals[p0]
        val inflater = LayoutInflater.from(context)
        var holder = ViewHolder()
        val myView = inflater.inflate(R.layout.animal_ticket, null)
        myView.tvName.text = animal.name!!
        myView.tvDes.text = animal.description!!
        myView.jvAnimalImage.setImageResource(animal.image!!)
        return myView
    }

Answer 1

如果之前另一个View相同的视图类型（getItemViewType(position: Int)返回相同的值）滚动屏幕，列表视图可能会将该实例作为第二个参数传递给{{1 }}。重新使用该视图比扩展新视图更快。

您还应该使用getView()来缓存有关视图的内容，例如相对昂贵的ViewHolder。您可以通过标记将其附加到视图中并从视图中检索它。

findViewById()

Answer 2

对于任何RecyclerView，您需要自己的ViewHolder类，其中包含animal_ticket中列出的所有视图。

基本上，它的工作原理如下：

1）创建＆＃39;持有的ViewHolder。您要显示的项目的所有视图;

2）将ViewHolder绑定到RecyclerView并为内部视图指定值;

这是我写的一个示例适配器：

class MyActivity : Activity() {
//users is the list we're going to use to get information for the views
val users = ArrayList<User>()
//...getting user information
//.. your activity stuff here

//Creating our adapter
/* 
  Note that to extend the RecyclerView.Adapter, you need to specify a
  ViewHolder. The code becomes much easier to manage if you just put the 
  ViewHolder inside your adapter.
*/
inner class MyAdapter : RecyclerView.Adapter<MyAdapter.MyViewHolder>() {

    //This is the view holder
    inner class MyViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        //Here you declare your views and get them from the itemView
        //The itemView is one that is passed each time to the RecyclerView
        //(the items inside your XML layout file)
        internal val userImageView = itemView.findViewById(R.id.userImage)
        internal val userFullName = itemView.findViewById(R.id.userName)
    }

    //This is where you return your own ViewHolder with your layout
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
        val layoutInflater = LayoutInflater.from(parent.context)
        //user_list_item.xml is below
        val itemView = layoutInflater.inflate(R.layout.user_list_item, parent, false))
        return MyViewHolder(itemView)
    }


    //In here is where you want to set your values for the views
    override fun onBindViewHolder(holder: SentRequestViewHolder, position: Int) {
        val currentUser = users[position]

        holder.userImage.drawable = currentUser.drawable
        holder.userFullName.text = currentUser.name
    }

    //You must override this method as well for the adapter to work properly
    override fun getItemCount() = users.size
}

使用RecyclerView.Adapter时必须覆盖这些方法

这是user_list_item.xml

<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="100dp">

    <ImageView
        android:id="@+id/userImage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <TextView
        android:id="@+id/userName"
        android:layout_below="@id/userImage"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

 </RelativeLayout>

视图适配器的无条件布局膨胀。科特林

2 个答案: