android - RecyclerView 和 onClicklistener

Question

我在 MainActivity 中使用此代码，但我无法在 MainActivity 中访问 setOnMenuItemClickListener。

MainActivity 类:

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.widget.ImageView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity   {
    Toast toast ;
    ImageView hahaha;
    protected static int ss=77;
    //recyclerview objects
    private RecyclerView recyclerView;
    private RecyclerView.LayoutManager layoutManager;
    private RecyclerView.Adapter adapter;
    public  int xxx=222;

    //model object for our list data
    private List<MyList> list;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //initializing views
        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));




        list = new ArrayList<>();

        //loading list view item with this function
        loadRecyclerViewItem();
    }

    private void loadRecyclerViewItem() {
        //you can fetch the data from server or some apis
        //for this tutorial I am adding some dummy data directly
        for (int i = 1; i <= 7; i++) {
            MyList myList = new MyList(
                    "Heading " + i,
                    "id = " + i,
                    "https://mediaresources.idiva.com/media//content/2014/May/diet_kids_health1.jpg",
                    "HHHHHH" + i

            );
            list.add(myList);
        }

        adapter = new CustomAdapter(list, this);
        recyclerView.setAdapter(adapter);

    }
}

这是 CustomAdaptor.class

import android.content.Context;
import android.support.v7.widget.PopupMenu;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.bumptech.glide.Glide;

import java.util.List;


public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {

    private List<MyList> list;
    private Context mCtx;


    public CustomAdapter(List<MyList> list, Context mCtx) {
        this.list = list;
        this.mCtx = mCtx;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.list_items, parent, false);
        return new ViewHolder(v);
    }


    @Override
    public void onBindViewHolder(final CustomAdapter.ViewHolder holder, final int position) {
        MyList myList = list.get(position);


        //loading the image
        Glide.with(mCtx)
                .load(myList.getUrl())
                .into(holder.imageView);

        holder.textViewHead.setText(myList.getHead());
        holder.textViewDesc.setText(myList.getDesc());
        //holder.textViewDesc.setText(myList.getIdofdata());
        holder.buttonViewOption.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                //creating a popup menu
                PopupMenu popup = new PopupMenu(mCtx, holder.buttonViewOption);
                //inflating menu from xml resource
                popup.inflate(R.menu.options_menu);
                //adding click listener
                popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                    @Override
                    public boolean onMenuItemClick(MenuItem item) {
                        switch (item.getItemId()) {
                            case R.id.menu1:
                                //handle menu1 click
                                holder.textViewHead.setText("moshiri" + holder.textViewHead.getText()  );
                                break;
                            case R.id.menu2:
                                //holder.textViewHead.setText("new" + holder.textViewDesc.getText()  );
                                holder.textViewHead.setText("mohsen hi dear");
                                break;
                            case R.id.menu3:
                                holder.textViewHead.setText("@@@@@@@@@@@@@@@@@@" + list.indexOf(this));
                                holder.textViewDesc.setText("############" + list.indexOf(this));
                                //MainActivity me=new MainActivity();
                                MainActivity.ss=77;
                                removeItem(3);

                                break;
                        }
                        return false;
                    }
                });
                //displaying the popup
                popup.show();

            }
        });
    }


    @Override
    public int getItemCount() {
        return list.size();
    }



    public void removeItem(int position) {
        list.remove(position);
        notifyItemRemoved(position);
        notifyItemRangeChanged(position, getItemCount() );
//      notifyDataSetChanged();
    }





    public class ViewHolder extends RecyclerView.ViewHolder {

        public TextView textViewHead;
        public TextView textViewDesc;
        public TextView buttonViewOption;
        public ImageView imageView;

        public ViewHolder(View itemView) {
            super(itemView);
            textViewHead = (TextView) itemView.findViewById(R.id.textViewHead);
            textViewDesc = (TextView) itemView.findViewById(R.id.textViewDesc);
            buttonViewOption = (TextView) itemView.findViewById(R.id.textViewOptions);
            imageView = (ImageView) itemView.findViewById(R.id.imageView);
        }
    }

}

在 CustomAdaptor 中，我在菜单和按钮中访问 onclick 监听器，但我无法在 MainActivity 中管理菜单和按钮。如何在 mainActivity 中使用 Listener 或者如何将更改从 CustomAdaptor 发送到 mainActivity？

Answer 1

为此目的使用接口(interface)。在您的 CustomAdapter 中声明该接口(interface)，并在 ViewHolder 中覆盖点击监听器方法并从您想要的适配器传递项目。目前我正在传递位置，只有你可以在这里传递任何东西。我已经对您的代码进行了更改，请在下面查看。

import android.content.Context;
import android.support.v7.widget.PopupMenu;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.bumptech.glide.Glide;

import java.util.List;

public class CustomAdapter extends RecyclerView.Adapter<CustomAdapter.ViewHolder> {

    protected CustomClicklistener mListener;
    private List<MyList> list;
    private Context mCtx;
    private CustomClicklistener clickListener;

    public interface CustomClicklistener {
        void onItemClick(int position);
    }

    public CustomAdapter(List<MyList> list, Context mCtx, CustomClicklistener
            clickListener) {
        this.list = list;
        this.mCtx = mCtx;
        this.clickListener = clickListener;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.list_items, parent, false);
        return new ViewHolder(v);
    }


    @Override
    public void onBindViewHolder(final CustomAdapter.ViewHolder holder, final int position) {
        MyList myList = list.get(position);


        //loading the image
        Glide.with(mCtx)
                .load(myList.getUrl())
                .into(holder.imageView);

        holder.textViewHead.setText(myList.getHead());
        holder.textViewDesc.setText(myList.getDesc());
        //holder.textViewDesc.setText(myList.getIdofdata());
        holder.buttonViewOption.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                //creating a popup menu
                PopupMenu popup = new PopupMenu(mCtx, holder.buttonViewOption);
                //inflating menu from xml resource
                popup.inflate(R.menu.options_menu);
                //adding click listener
                popup.setOnMenuItemClickListener(new PopupMenu.OnMenuItemClickListener() {
                    @Override
                    public boolean onMenuItemClick(MenuItem item) {
                        switch (item.getItemId()) {
                            case R.id.menu1:
                                //handle menu1 click
                                holder.textViewHead.setText("moshiri" + holder.textViewHead.getText()  );

                                break;
                            case R.id.menu2:
                                //holder.textViewHead.setText("new" + holder.textViewDesc.getText()  );
                                holder.textViewHead.setText("mohsen hi dear");
                                break;
                            case R.id.menu3:
                                holder.textViewHead.setText("@@@@@@@@@@@@@@@@@@" + list.indexOf(this));
                                holder.textViewDesc.setText("############" + list.indexOf(this));
                                //MainActivity me=new MainActivity();
                                MainActivity.ss=77;
                                removeItem(3);

                                break;
                        }
                        return false;
                    }
                });
                //displaying the popup
                popup.show();

            }
        });
    }


    @Override
    public int getItemCount() {
        return list.size();
    }



    public void removeItem(int position) {
        list.remove(position);
        notifyItemRemoved(position);
        notifyItemRangeChanged(position, getItemCount() );
        //      notifyDataSetChanged();
    }





    public class ViewHolder extends RecyclerView.ViewHolder  implements View.OnClickListener  {

        public TextView textViewHead;
        public TextView textViewDesc;
        public TextView buttonViewOption;
        public ImageView imageView;

        public ViewHolder(View itemView) {
            super(itemView);
            itemView.setOnClickListener(this);

            textViewHead = (TextView) itemView.findViewById(R.id.textViewHead);
            textViewDesc = (TextView) itemView.findViewById(R.id.textViewDesc);
            buttonViewOption = (TextView) itemView.findViewById(R.id.textViewOptions);
            imageView = (ImageView) itemView.findViewById(R.id.imageView);
        }

        @Override
        public void onClick(View view) {
            if (mListener != null) {
                mListener.onItemClick(getAdapterPosition());
                notifyDataSetChanged();
            }
        }
    }

}

在 MainActivity 中，您可以在最后的 oncCreate 方法中获得如下所示的点击监听器

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.widget.ImageView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;


public class MainActivity extends AppCompatActivity   {
    CustomAdapter.CustomClicklistener clickListener;
    Toast toast ;
    ImageView hahaha;
    protected static int ss=77;
    //recyclerview objects
    private RecyclerView recyclerView;
    private RecyclerView.LayoutManager layoutManager;
    private RecyclerView.Adapter adapter;
    public  int xxx=222;

    //model object for our list data
    private List<MyList> list;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //initializing views
        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        recyclerView.setHasFixedSize(true);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));




        list = new ArrayList<>();
        //loading list view item with this function
        loadRecyclerViewItem();



        clickListener = new CustomAdapter.CustomClicklistener() {
            @Override
            public void onItemClick(int position) {
                // Do what you want here
                Toast.makeText(MainActivity.this, "This ... " , Toast.LENGTH_LONG).show();
            }
        };







    }

    private void loadRecyclerViewItem() {
        //you can fetch the data from server or some apis
        //for this tutorial I am adding some dummy data directly
        for (int i = 1; i <= 7; i++) {
            MyList myList = new MyList(
                    "Heading " + i,
                    "id = " + i,
                    "https://media.alalamtv.net/news/image/855x495//2015/02/16/alalam_635596703961833722_25f_4x3.jpg",
                    "HHHHHH" + i

            );
            list.add(myList);
        }

        adapter = new CustomAdapter(list, this, clickListener);
        recyclerView.setAdapter(adapter);

    }
}