无法使用选择器突出显示 RecyclerView 中的项目

Question

我只想在按下项目时突出显示它。

我在下面有选择器 (@drawable/expandable_menu)

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android"
android:exitFadeDuration="@android:integer/config_mediumAnimTime">
<item android:drawable="@color/purple_200" android:state_pressed="true" />
<item android:drawable="@color/purple_500" android:state_selected="true" />
<item android:drawable="@color/chat" android:state_activated="true" />
<item android:drawable="@color/transparent"/>
</selector>

在我的 onclick 监听器中，我选择了这个项目

RecyclerView XML：

<androidx.recyclerview.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginBottom="70dp"
        android:id="@+id/chat_messages"
        app:stackFromEnd="true"
        android:clickable="true"
        android:focusableInTouchMode="true"
        android:background="@drawable/expandable_menu"
        app:layoutManager="androidx.recyclerview.widget.LinearLayoutManager"
        android:focusable="true">

消息 XML：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="10dp"
android:paddingLeft="5dp"
android:paddingRight="5dp"
android:paddingTop="10dp"
android:layout_gravity="left"
>

<TextView
    android:id="@+id/chat_msg_send"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="this is me"
    android:textColor="@color/black"
    android:textSize="16dp"
    android:background="@color/cardview_shadow_start_color"
    android:padding="10dp"
    android:layout_alignParentTop="true" />
 </RelativeLayout>

我关注了这个答案 (https://stackoverflow.com/a/30046476) 但没有成功

Answer 1

您必须将OnClickListener 设置为View，将选择器设置为背景。我看到你为TextView（孩子）设置了选择器，你是设置onClick到这个View还是整个itemView（在你的情况下是rootRelativeLayout）？

您也可以尝试为TextView 添加android:duplicateParentState - 这应该使TextView 在按下父级时绘制按下状态，而不仅仅是TextView 本身（当没有OnClickListener 时根本不可点击设置）

Answer 2

In this tutorial, i would explain how you can load a recyclerview with the first item selected (background color changed) and also make the background of the other items changed when clicked.
Follow the step by step process.

[Highlighted selected item in recycler view screenshot][1]
[1]:   https://i.stack.imgur.com/hHP0W.png

You can see full steps of RecyclerView Highlighted items


Start by creating a new Android Studio project. Go to File -> New Project.
Open your color file `(res -> values -> colors.xml)`. Paste the below code.
colors.xml

>     <resources>
>         <color name="colorPrimaryLight">#07C4AF</color>
>         <color name="colorPrimary">#035F56</color>
>         <color name="colorPrimaryDark">#00574B</color>
>         <color name="colorAccent">#D81B60</color>
>      
>     </resources>

 **create a new android resource layout. Right click on your project file, select New -> Android Resource Layout . give it the name “recycler_items”.**

**recycler_items.xml**
  

  <android.support.v7.widget.CardView
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/cardview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        card_view:contentPaddingLeft="18dp"
        card_view:contentPaddingRight="18dp"
        card_view:cardCornerRadius="15dp"
        card_view:cardElevation="7dp"
        card_view:cardBackgroundColor="@color/colorPrimary"
        android:layout_marginLeft="8dp"
     
        >
     
        <TextView
            android:id="@+id/tv_pets"
            android:layout_gravity="center"
            android:textSize="15dp"
            android:layout_marginTop="5dp"
            android:layout_marginBottom="5dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Pet Name"
            android:textColor="#fff"/>
     
    </android.support.v7.widget.CardView>
     

 **Right click on your project file, select New -> Java Class. Give it the name “RecyclerAdapter“. This is the adapter that would be used to populate our recyclerview.**

       
    
    import android.content.Context;
    import android.support.v7.widget.CardView;
    import android.support.v7.widget.RecyclerView;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ImageView;
    import android.widget.TextView;
    import java.util.List;
     
    public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.MyViewHolder>  {
     
        private List<Pets> petsList;
        private Context context;
        private static int lastClickedPosition = -1;
        private int selectedItem;
     
        public RecyclerAdapter(Context context, List<Pets> petsList) {
            this.context = context;
            this.petsList = petsList;
            selectedItem = 0;
        }
     
        @Override
        public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View itemView = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.recycler_items, parent, false);
     
            return new MyViewHolder(itemView);
        }
     
        @Override
        public void onBindViewHolder(final MyViewHolder holder, final int position) {
            holder.itemView.setTag(petsList.get(position));
            holder.name.setText(petsList.get(position).getName());
     
            holder.cardView.setCardBackgroundColor(context.getResources().getColor(R.color.colorPrimaryLight));
     
            if (selectedItem == position) {
                holder.cardView.setCardBackgroundColor(context.getResources().getColor(R.color.colorPrimaryDark));
            }
     
     
     
            holder.itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
     
                    int previousItem = selectedItem;
                    selectedItem = position;
     
                    notifyItemChanged(previousItem);
                    notifyItemChanged(position);
     
     
     
                }
            });
     
        }
     
     
        @Override
        public int getItemCount() {
            return petsList.size();
        }
     
     
     
     
        public class MyViewHolder extends RecyclerView.ViewHolder {
            public TextView name;
     
            public CardView cardView;
     
            public MyViewHolder(View view) {
                super(view);
                name = (TextView) view.findViewById(R.id.tv_pets);
                cardView = (CardView) view.findViewById(R.id.cardview);
     
            }
        }
     
    }
    
> Lets create our model class that holds information about the pets

 

Pets.java

 package androidnoon.recyclerview.select;
 public class Pets {
     
    private int id;
    private String Name;
    private String Description;
 
    public Pets(int id, String name, String description) {
        this.id = id;
        Name = name;
        Description = description;
    }
 
    public int getId() {
        return id;
    }
 
    public void setId(int id) {
        this.id = id;
    }
 
    public String getName() {
        return Name;
    }
 
    public void setName(String name) {
        Name = name;
    }
 
    public String getDescription() {
        return Description;
    }
 
    public void setDescription(String description) {
        Description = description;
    }
}
      activity_main.xml
    
   <android.support.design.widget.CoordinatorLayout   

 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:app="http://schemas.android.com/apk/res-auto"
 xmlns:tools="http://schemas.android.com/tools" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent"  
  tools:context=".MainActivity">

 <android.support.design.widget.AppBarLayout android:layout_width="match_parent" 
android:layout_height="wrap_content" android:theme="@style/AppTheme.AppBarOverlay">
         
 <android.support.v7.widget.Toolbar
 android:id="@+id/toolbar" 
 android:layout_width="match_parent"
 android:layout_height="?attr/actionBarSize"
 android:background="?attr/colorPrimary" 
 app:popupTheme="@style/AppTheme.PopupOverlay" />
         
  </android.support.design.widget.AppBarLayout>
         
    <android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" 

android:layout_width="match_parent" 
android:layout_height="match_parent" app:layout_behavior="@string/appbar_scrolling_view_behavior" tools:context=".MainActivity" 
tools:showIn="@layout/activity_main">
                <android.support.v7.widget.RecyclerView 
 android:id="@+id/RvPets"
 android:layout_marginTop="20dp"
 android:layout_width="match_parent" 
 android:layout_height="match_parent">
</android.support.v7.widget.RecyclerView>
         
            </android.support.constraint.ConstraintLayout>
         
         
        </android.support.design.widget.CoordinatorLayout>

 

    **MainActivity.java**
import android.content.Context;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
 
import java.util.ArrayList;
import java.util.List;
 
public class MainActivity extends AppCompatActivity {
 
    RecyclerView RvPets;

    List<Pets> petsList = new ArrayList<>();
    RecyclerAdapter recyclerAdapter;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
 
        recyclerAdapter = new RecyclerAdapter(MainActivity.this, petsList);
        RvPets = (RecyclerView) findViewById(R.id.RvPets);
 
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(MainActivity.this, LinearLayoutManager.HORIZONTAL, false);
 
        RvPets.setLayoutManager(linearLayoutManager);
 
        RvPets.setAdapter(recyclerAdapter);
        preparePetsData();
 
    }
 
    private void preparePetsData() {

        Pets pet = new Pets(1, "Cat", "Cute, has 4 legs");

        petsList.add(pet);
 
        pet = new Pets(2, "Bird", "Can Fly, has 2 legs");

        petsList.add(pet);
 
        pet = new Pets(3, "Dog", "Cute, has 4 legs");

        petsList.add(pet);
 
        pet = new Pets(4, "Fish", "has no leg");

        petsList.add(pet);
 
        pet = new Pets(5, "Hamster", "Cute, has 4 legs");
        petsList.add(pet);
 
        recyclerAdapter.notifyDataSetChanged();
 
    }
 
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }
 
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
 
        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }
 
        return super.onOptionsItemSelected(item);
    }
}