Android RecyclerView选择多个item的实现代码

模仿网易新闻客户端阅读偏好的频道选择，先看实现的页面：

直接上代码：

import android.content.res.Resources;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;
import android.util.Log;
import android.util.SparseBooleanArray;
import android.view.View;

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

public class RecyclerViewActivity extends AppCompatActivity {
 private RecyclerView recycler;
 private RecyclerAdapter mAdapter;
 private List<PreferCustomizableChannel> channels = new ArrayList<>();
 private List<PreferCustomizableChannel> channelsSelected;

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

initData();

initUI();

findViewById(R.id.resultBTN).setOnClickListener(new View.OnClickListener() {
     @Override
     public void onClick(View v) {
       int lens = channelsSelected.size();
       for (int i =0 ; i < lens; i++) {
         PreferCustomizableChannel customizableChannel = channelsSelected.get(i);
         if (customizableChannel.isSelected()) {
           Log.i("RecyclerViewActivity", "onClick: "+customizableChannel.toString());
         }
       }
     }
   });
 }

private void initData() {
   Resources resources = getResources();
   TypedArray array = resources.obtainTypedArray(R.array.prefer_channel_icon);
   int len = array.length();
   String[] name = resources.getStringArray(R.array.prefer_channel_name);
   for (int i = 0; i < len; i++) {
     PreferCustomizableChannel customizableChannel = new PreferCustomizableChannel();
     customizableChannel.setChannel(name[i]);
     customizableChannel.setResId(array.getResourceId(i, 0));
     customizableChannel.setSelected(false);
     customizableChannel.setId(i * 100);
     channels.add(customizableChannel);
   }
   array.recycle();
   channelsSelected = channels;
 }

private void initUI() {
   recycler = (RecyclerView) findViewById(R.id.recycler);
   final GridLayoutManager manager = new GridLayoutManager(this, 3);
   recycler.setLayoutManager(manager);
   recycler.setHasFixedSize(true);
   recycler.setItemAnimator(new DefaultItemAnimator());
   mAdapter = new RecyclerAdapter(RecyclerViewActivity.this, channels);
   recycler.setAdapter(mAdapter);
   mAdapter.setClickListener(new OnRecyclerViewItemClickListener() {
     @Override
     public void onItemClick(View view, int position) {
       SparseBooleanArray selecteds = mAdapter.getSelectedItem();
       int len = channels.size();
       for (int i = 0; i < len; i++) {
         if (selecteds.get(i)) {
           channelsSelected.get(position).setSelected(true);
         }
       }
     }
   });
 }
}

布局文件RecyclerView横竖都是“match_parent”,否则在点击的时候gridView会自动上滑一段距离。

适配器的实现：

import android.support.v7.widget.RecyclerView;
import android.util.SparseBooleanArray;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

import com.entity.PreferCustomizableChannel;
import com.listener.OnRecyclerItemClickListener;

import java.util.List;

import butterknife.BindView;
import butterknife.ButterKnife;

public class PreferChannelAdapter extends RecyclerView.Adapter<PreferChannelAdapter.PreferChannelHolder>{
 private List<PreferCustomizableChannel> lists;
 private OnRecyclerItemClickListener listener;
 private SparseBooleanArray selectLists = new SparseBooleanArray();

public PreferChannelAdapter() {
 }

public void setDatas(List<PreferCustomizableChannel> lists) {
   this.lists = lists;
   notifyDataSetChanged();
 }

public void setOnItemClickListener(OnRecyclerItemClickListener listener) {
   this.listener = listener;
 }

@Override
 public PreferChannelHolder onCreateViewHolder(ViewGroup parent, int viewType) {
   View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.prefer_channel_item, null);
   return new PreferChannelHolder(view);
 }

@Override
 public void onBindViewHolder(final PreferChannelHolder holder, final int position) {
   PreferCustomizableChannel channelItem = lists.get(position);
   holder.channelItemTV.setText(channelItem.getChannel());
   holder.channelItemImg.setImageResource(channelItem.getResId());
   if (!selectLists.get(position)) {
     holder.selectedMarkImg.setVisibility(View.GONE);
   } else {
     holder.selectedMarkImg.setVisibility(View.VISIBLE);
   }
   holder.preferChannelItemLayout.setOnClickListener(new View.OnClickListener() {
     @Override
     public void onClick(View view) {
       if (holder.selectedMarkImg.getVisibility() == View.GONE) {
         holder.selectedMarkImg.setVisibility(View.VISIBLE);
         selectLists.put(position, true);
       } else if (holder.selectedMarkImg.getVisibility() == View.VISIBLE){
         holder.selectedMarkImg.setVisibility(View.GONE);
         selectLists.put(position, false);
       }
       listener.onRecyclerClick(position);
     }
   });
 }

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

public class PreferChannelHolder extends RecyclerView.ViewHolder {
   @BindView(R.id.preferChannelItemLayout)
   RelativeLayout preferChannelItemLayout;
   @BindView(R.id.channelItemTV)
   TextView channelItemTV;
   @BindView(R.id.channelItemImg)
   ImageView channelItemImg;
   @BindView(R.id.selectedMarkImg)
   ImageView selectedMarkImg;

public PreferChannelHolder(View itemView) {
     super(itemView);
     ButterKnife.bind(this, itemView);
   }
 }

public SparseBooleanArray getSelectedItem() {
   return selectLists;
 }
}

顺便把item的布局也贴出来吧：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:id="@+id/preferChannelItemLayout"
 android:gravity="center"
 android:layout_gravity="center"
 android:layout_marginTop="10dp"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content">
 <!--android:gravity="center"
 android:layout_gravity="center"-->
 <ImageView
   android:id="@+id/channelItemImg"
   android:scaleType="centerInside"
   android:layout_width="68dp"
   android:layout_height="wrap_content"/>
 <TextView
   android:id="@+id/channelItemTV"
   android:gravity="center"
   android:layout_marginLeft="20dp"
   android:layout_marginRight="20dp"
   android:layout_marginBottom="20dp"
   android:layout_marginTop="8dp"
   android:layout_below="@id/channelItemImg"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content" />
 <ImageView
   android:id="@+id/selectedMarkImg"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:layout_centerVertical="true"
   android:visibility="gone"
   android:layout_alignRight="@id/channelItemImg"
   android:src="@mipmap/prefer_selected"/>
</RelativeLayout>

其他注意的地方：

SpareBooleanArrary.size()返回的是已经设置为true的长度，比如选择了一个则返回1，选择了10则返回10，但在选择了10后去掉一个的时候，size()返回的并不是9，而依然是10，这点注意，所以在遍历的时候并没有使用使用size()取长度。