如何将单击侦听器添加到 Recycler View 的子级？

Question

Here is my discussion.java which contains the RecyclerView

public class Discussion extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_discussion);
        RecyclerView mRecycleview =(RecyclerView)findViewById(R.id.cycleview);
        mRecycleview.setLayoutManager(new LinearLayoutManager(this));
        String[] use ={"a","b"};
        String[] lo={"be","ndls"};
        String[] ti={"12:00","11:00"};
        String[] staus={"Today","Tommmorow"};
        int[] posimg={R.drawable.img_post1,R.drawable.img_post2};

        mRecycleview.setAdapter(new FeedAdapter(use,lo,ti,staus,posimg));
        @NonNull
        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Open Activity for posting", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        // Functionality for poll
    }
}

Here is my FeedAdapter for the RecyclerView which is taking from resource layout file content.xml .

public class FeedAdapter extends 
    RecyclerView.Adapter<FeedAdapter.FeedViewHolder> {

    private  String[] userdata;
    private  String[] locdata;
    private  String[] timedata;
    private  int[]   postdata;
    private  String[] statusdata;

    public  FeedAdapter(String[] userdata,String[] locdata,String[] timedata,String[] statusdata,int[] postdata){
        this.userdata=userdata;
        this.locdata=locdata;
        this.postdata=postdata;
        this.statusdata=statusdata;
        this.timedata=timedata;
    }

    @Override
    public FeedViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater=LayoutInflater.from(parent.getContext());
        View view =inflater.inflate(R.layout.backupofcontent,parent,false);
        return new FeedViewHolder(view);
    }

    @Override
    public void onBindViewHolder( FeedAdapter.FeedViewHolder holder, int position) {
        String user=userdata[position];
        String loc=locdata[position];
        String time=timedata[position];
        String status=statusdata[position];
        int post=postdata[position];
        holder.username.setText(user);
        holder.locationa.setText(loc);
        holder.timea.setText(time);
        holder.statusa.setText(status);
        if(post==0)
            holder.postimg.setVisibility(View.GONE);
        else
            holder.postimg.setImageResource(post);
    }

    @Override
    public int getItemCount() {
        return userdata.length;
    }

    public class FeedViewHolder extends RecyclerView.ViewHolder{

        ImageView postimg;
        TextView username;
        TextView locationa;
        TextView timea;
        TextView statusa;

        public FeedViewHolder(View itemView) {
            super(itemView);
            postimg=itemView.findViewById(R.id.imgView_postPic);
            username=itemView.findViewById(R.id.user_name);
            locationa=itemView.findViewById(R.id.Location);
            timea=itemView.findViewById(R.id.Time);
            statusa=itemView.findViewById(R.id.post_text);
        }
    }
}

Here is my content.xml from which adapter is taking the feed. I want to set up the onClickListner on the view id:likelayout" or like so that when it is clicked, some actions are to be performed. For now, a toast would be enough.

Please help me out how to do it.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout

    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    android:orientation="vertical"
    tools:showIn="@layout/app_bar_main"
    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">

    <TextView
        android:id="@+id/user_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center|center_vertical"
        android:layout_marginLeft="5dp"
        android:layout_marginTop="4dp"
        android:text="User"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/Time"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/user_name"
        android:layout_gravity="center|center_vertical"
        android:layout_marginLeft="5dp"
        android:layout_marginTop="4dp"
        android:text="Time"
        android:textSize="10sp" />

    <TextView
        android:id="@+id/Location"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/Time"
        android:layout_gravity="center|center_vertical"
        android:layout_marginLeft="5dp"
        android:layout_marginTop="4dp"
        android:text="Location"
        android:textSize="10sp" />

    <LinearLayout
        android:id="@+id/layout_post"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/Location"
        android:layout_marginTop="10dp"
        android:orientation="vertical">

        <ImageView
            android:id="@+id/imgView_postPic"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:scaleType="fitCenter"
            android:src="@drawable/img_post1" />

        <ScrollView
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_marginTop="10dp"
            android:layout_marginBottom="55dp"
            android:layout_weight="1">

            <TextView
                android:id="@+id/post_text"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Status " />
        </ScrollView>

    </LinearLayout>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="20dp"
        android:layout_marginBottom="10dp"
        android:gravity="center_vertical"
        android:layout_above="@id/bottomnav">

        <TextView
            android:id="@+id/likecount"
            android:layout_marginLeft="20dp"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="0"
            android:gravity="center" />
        <TextView
            android:id="@+id/likecounttext"
            android:layout_toRightOf="@id/likecount"
            android:layout_marginLeft="10dp"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:text="Liked"/>
        <TextView
            android:layout_toRightOf="@id/likecounttext"
            android:layout_marginLeft="15dp"
            android:id="@+id/countsepartor"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="|"/>
        <TextView
            android:id="@+id/commentcount"
            android:layout_marginLeft="15dp"
            android:layout_toRightOf="@id/countsepartor"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="0"/>
        <TextView
            android:layout_marginLeft="10dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_toRightOf="@id/commentcount"
            android:text="Comments"/>

    </RelativeLayout>
    <LinearLayout
        android:id="@+id/bottomnav"
        android:layout_width="match_parent"
        android:layout_height="30dp"
        android:weightSum="3"
        android:layout_marginBottom="5dp"
        android:layout_alignParentBottom="true"
        android:orientation="horizontal">

        <LinearLayout
            android:id="@+id/likelayout"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_marginLeft="5dp"
            android:layout_gravity="center_vertical"
            android:layout_height="wrap_content">
            <ImageView
                android:layout_width="25dp"
                android:layout_height="wrap_content"
                android:src="@drawable/like"/>
            <TextView
                android:id="@+id/like"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Like"
                android:layout_marginLeft="10dp"
                android:layout_gravity="center_vertical"
                android:textSize="15sp"/>
        </LinearLayout>

        <LinearLayout
            android:id="@+id/commentlayout"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:layout_gravity="center_vertical"
            android:layout_height="wrap_content">
            <ImageView
                android:layout_width="25dp"
                android:layout_height="wrap_content"
                android:src="@drawable/comment"/>
            <TextView
                android:id="@+id/comment"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Comment"
                android:layout_marginLeft="10dp"
                android:layout_gravity="center_vertical"
                android:textSize="15sp"/>
        </LinearLayout>
        <LinearLayout
            android:id="@+id/polllayout"
            android:layout_width="0dp"
            android:layout_weight="1"
            android:gravity="center"
            android:layout_gravity="center_vertical"
            android:layout_height="wrap_content">
            <ImageView
                android:layout_width="25dp"
                android:layout_height="wrap_content"
                android:src="@drawable/poll"/>
            <TextView
                android:id="@+id/poll"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Poll"
                android:layout_marginLeft="10dp"
                android:layout_gravity="center_vertical"
                android:textSize="15sp"/>
        </LinearLayout>
    </LinearLayout>
</RelativeLayout>

Answer 1

In your onBindViewHolder function, just add a click listener like the following.

@Override
public void onBindViewHolder( FeedAdapter.FeedViewHolder holder, int position) {
    String user=userdata[position];
    String loc=locdata[position];
    String time=timedata[position];
    String status=statusdata[position];
    int post=postdata[position];
    holder.username.setText(user);
    holder.locationa.setText(loc);
    holder.timea.setText(time);
    holder.statusa.setText(status);

    if(post==0)
        holder.postimg.setVisibility(View.GONE);
    else
        holder.postimg.setImageResource(post);

    holder.username.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View view) {
            // Do something. 
        }
    });
}

If you want to set up the click listener to the other UI elements in your list item, then just declare them like the way you have declared username , timea , statusa etc. and then add the listener to it.

Please keep in mind that, in order to make an ImageView clickable you need to add the clickable attribute to true in your layout file. For example, if you need to make your like image clickable, you need to add the clickable attribute like the following.

<ImageView
    android:id="@+id/like_image"
    android:layout_width="25dp"
    android:layout_height="wrap_content"
    android:clickable="true"
    android:src="@drawable/like"/>

In order to show a Toast on clicking the item, you need to have the Context of the Discussion activity while you are creating the adapter. So I would like to suggest you modify the constructor of the adapter like the following.

public class FeedAdapter extends 
    RecyclerView.Adapter<FeedAdapter.FeedViewHolder> {

    private  String[] userdata;
    private  String[] locdata;
    private  String[] timedata;
    private  int[]   postdata;
    private  String[] statusdata;

    // Add another extra variable to store context
    // The context is necessary for showing toast
    private Context context; 

    public  FeedAdapter(String[] userdata, String[] locdata,String[] timedata, String[] statusdata, int[] postdata, Context context){
        this.userdata = userdata;
        this.locdata = locdata;
        this.postdata = postdata;
        this.statusdata = statusdata;
        this.timedata = timedata;
        this.context = context; // Initialize it here
    }

    @Override
    public FeedViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        LayoutInflater inflater=LayoutInflater.from(parent.getContext());
        View view =inflater.inflate(R.layout.backupofcontent,parent,false);
        return new FeedViewHolder(view);
    }

    @Override
    public void onBindViewHolder( FeedAdapter.FeedViewHolder holder, int position) {
        String user=userdata[position];
        String loc=locdata[position];
        String time=timedata[position];
        String status=statusdata[position];
        int post=postdata[position];
        holder.username.setText(user);
        holder.locationa.setText(loc);
        holder.timea.setText(time);
        holder.statusa.setText(status);

        if(post==0)
            holder.postimg.setVisibility(View.GONE);
        else
            holder.postimg.setImageResource(post);

        // Use the context here to show the Toast 
        holder.username.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(context, "Something", Toast.LENGTH_LOGN).show();
            }
        });
    }

    @Override
    public int getItemCount() {
        return userdata.length;
    }

    public class FeedViewHolder extends RecyclerView.ViewHolder{

        ImageView postimg;
        TextView username;
        TextView locationa;
        TextView timea;
        TextView statusa;

        public FeedViewHolder(View itemView) {
            super(itemView);
            postimg=itemView.findViewById(R.id.imgView_postPic);
            username=itemView.findViewById(R.id.user_name);
            locationa=itemView.findViewById(R.id.Location);
            timea=itemView.findViewById(R.id.Time);
            statusa=itemView.findViewById(R.id.post_text);
        }
    }
}

And to adopt the changes of the modified constructor, the adapter needs to be initialized like the following from your Discussion class.

mRecycleview.setAdapter(new FeedAdapter(use, lo, ti, staus, posimg, this));

Hope that helps!

Answer 2

same as the other views, in the FeedViewHolder class add a LinearLayout variable:

LinearLayout like;

then

like = itemView.findViewById(R.id.likelayout);

then in onBindViewHolder use :

holder.like.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                // Like Layout was clicked
            }
        });