從視圖適配器無條件佈局通貨膨脹。 kotlin

Question

我在Android Studio中收到以下警告： 「視圖適配器的無條件佈局膨脹：應使用視圖持有者模式（使用傳遞給此方法的循環視圖作爲第二個參數）以實現更流暢的滾動。在inflater.inflate（R.layout.animal_ticket，null）行。

如何修復警告？我無法找到解決這個問題的方法。

謝謝！

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

如果以前有相同的視圖類型（getItemViewType(position: Int)返回的值相同），該滾動離開屏幕的另一View，列表視圖，可以在該實例傳遞作爲第二個參數，以getView()。重複使用該視圖比誇大新視圖要快。

您還應該使用ViewHolder來緩存有關該視圖的內容，例如相對昂貴的findViewById()。您可以將它附加到標記視圖中並從中檢索它。

override fun getView(position: Int, convertView: View?, parent: ViewGroup?) { 
    val animal = listOfAnimals[position] 
    val myView = convertView ?: 
     LayoutInflater.from(context).inflate(R.layout.animal_ticket, parent, false) 
    val holder = myView.tag as? ViewHolder ?: ViewHolder(myView) 
    myView.tag = holder 
    holder.tvName.text = animal.name!! // etc 
} 

class ViewHolder(view: View) { 
    val tvName: TextView = view.name // etc 
} 

Answer 2

對於任何RecyclerView，你需要具有所有的內部animal_ticket列出的意見自己ViewHolder類。

基本上，它的工作原理是這樣的：

1）創建ViewHolder是「持有」你們要顯示的項目的意見;

2）將ViewHolder綁定到RecyclerView併爲其中的視圖賦值;

下面是一個例子適配器我寫道：

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 
} 

你必須重寫這些方法使用RecyclerView.Adapter

當這裏是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>