RecyclerView的好处
‘1.可以当ListView、GridView等布局使用、并且可以滚动设置方向、使用灵活
2.可以添加自定义动画、多布局使用ViewHolder拓展性好
注意事项’
1.支持listview、gridview、瀑布流（布局管理器不添加会导致数据不显示）
2.使用需要自定义滚动、点击、长按、下拉刷新、上拉加载事件的监听
3.滚动事件一定要用设置空闲状态刷新
newState == RecyclerView.SCROLL_STATE_IDLE
####并且一定是布局管理器对才能得到滚动当前可见第一个和最后一个Item
4.内部传递监听事件，可以定义接口，从Adapter传递出更多数据到Activity或者Fragment中
5.Adapter使用需要设置泛型<RecyclerView.ViewHolder> 并且内部ViewHolder要继承RecyclerView.ViewHolder，加载布局根据getItemType返回的值传递相应ViewHolder对象
6.设置数据源时要要判断ViewHolder的类型来决定加载什么数据
！！！如果使用要设置布局管理器对象，确定要使用哪种类型，不然不能看到数据
private void init() {
mRecyclerView = (RecyclerView)findViewById(R.id.recycler_view);
mList = new ArrayList<>();
mAdapter = new RecyclerAdapter(this,mList);
LinearLayoutManager lm = new LinearLayoutManager(this);
lm.setOrientation(LinearLayoutManager.VERTICAL);//线性
GridLayoutManager gm = new GridLayoutManager(this, 3, LinearLayoutManager.VERTICAL, false);//网格
StaggeredGridLayoutManager sgm = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);//瀑布流
// mRecyclerView.setLayoutManager(lm);
// mRecyclerView.setLayoutManager(gm);
mRecyclerView.setLayoutManager(sgm);
mRecyclerView.setAdapter(mAdapter);
}
=======================================================
Adapter
package mobi.xiaowu.recyclerview.adapter;
import android.content.Context;
import android.graphics.Color;
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;
import java.util.Random;
import mobi.xiaowu.recyclerview.R;
import mobi.xiaowu.recyclerview.model.Focus;
import mobi.xiaowu.recyclerview.utils.ImgAsync;
/**
* Created by xiaowu on 2016/12/21.
*/
public class Ex01Adapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> implements View.OnLongClickListener, View.OnClickListener {
private List<Focus.Item> mItems;
private Context mContext;
private LayoutInflater mInflater;
private OnItemClickListener mListener;
private OnItemLongClickListener mLongListener;
private RecyclerView mRecyclerView;
private static final int POSITION_SINGLE = 1;//设置单双行标记
private static final int POSITION_MULTIPLE = 2;
private Random rm;
public Ex01Adapter(Context context, List<Focus.Item> items) {
mContext = context;
mItems = items;
mInflater = LayoutInflater.from(mContext);
rm = new Random();
}
//初始化监听事件
public void setOnClickListener(OnItemClickListener listener) {
mListener = listener;
}
public void setOnLongClickListener(OnItemLongClickListener listener) {
mLongListener = listener;
}
/**
* 根据类型创建不同的布局
* @param parent
* @param viewType
* @return
*/
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = null;
RecyclerView.ViewHolder holder = null;
switch (viewType) {
case POSITION_SINGLE:
view = mInflater.inflate(R.layout.item_ex01, parent, false);
holder = new ViewHolder(view);
break;
case POSITION_MULTIPLE:
view = mInflater.inflate(R.layout.item_ex02, parent, false);
holder = new ViewHolder2(view);
break;
}
if (view != null) {
view.setOnClickListener(this);
view.setOnLongClickListener(this);
}
return holder;
}
/**
* 根据返回的ViewHolder类型加载不同数据
* @param holder
* @param position
*/
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
if (holder instanceof ViewHolder) {
ViewHolder vh = (ViewHolder) holder;
if (position >0) {
vh.mTextView.setText(mItems.get(position).getTitle());
}
else {
vh.mTextView.setText("");
}
vh.mImageView.setImageResource(R.mipmap.ic_launcher);
vh.mImageView.setTag(mItems.get(position).getCoverPath());
new ImgAsync(vh.mImageView).execute(mItems.get(position).getCoverPath());
}else if (holder instanceof ViewHolder2){
ViewHolder2 vh = (ViewHolder2) holder;
if (position >0) {
vh.mTextView.setText(mItems.get(position).getTitle());
}
else {
vh.mTextView.setText("");
}
vh.mTextView.setTextColor(Color.rgb(rm.nextInt(256),rm.nextInt(256),rm.nextInt(256)));//第二种布局使用的颜色随机
vh.mImageView.setImageResource(R.mipmap.ic_launcher);
vh.mImageView.setTag(mItems.get(position).getCoverPath());
new ImgAsync(vh.mImageView).execute(mItems.get(position).getCoverPath());
}
}
@Override
public int getItemCount() {
return mItems.size();
}
/**
* 返回布局的类型标识
* @param position
* @return
*/
@Override
public int getItemViewType(int position) {
return position%2==0 ?POSITION_SINGLE:POSITION_MULTIPLE;
}
//挂载RecyclerView
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
mRecyclerView = recyclerView;
}
@Override
public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
super.onDetachedFromRecyclerView(recyclerView);
mRecyclerView = null;
}
@Override
public boolean onLongClick(View v) {
int position = mRecyclerView.getChildAdapterPosition(v);
mLongListener.MyItemLongClick(mRecyclerView,v,position,mItems.get(position));
return true;
}
@Override
public void onClick(View v) {
int position = mRecyclerView.getChildAdapterPosition(v);
mListener.MyItemClick(mRecyclerView,v,position,mItems.get(position));
}
//接口
public interface OnItemClickListener{
void MyItemClick(RecyclerView recyclerView, View v, int position, Focus.Item data);
}
public interface OnItemLongClickListener {
void MyItemLongClick(RecyclerView recyclerView, View v, int position, Focus.Item data);
}
public static class ViewHolder extends RecyclerView.ViewHolder{
private TextView mTextView;
private ImageView mImageView;
public ViewHolder(View itemView) {
super(itemView);
mTextView = (TextView)itemView.findViewById(R.id.item_tv);
mImageView = (ImageView)itemView.findViewById(R.id.item_iv);
}
}
public static class ViewHolder2 extends RecyclerView.ViewHolder{
private TextView mTextView;
private ImageView mImageView;
public ViewHolder2(View itemView) {
super(itemView);
mTextView = (TextView)itemView.findViewById(R.id.item_tv);
mImageView = (ImageView)itemView.findViewById(R.id.item_iv);
}
}
}
Activity
package mobi.xiaowu.recyclerview;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.OnScrollListener;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.View;
import android.widget.RadioGroup;
import android.widget.Toast;
import com.google.gson.Gson;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
import mobi.xiaowu.recyclerview.adapter.Ex01Adapter;
import mobi.xiaowu.recyclerview.model.Focus;
import mobi.xiaowu.recyclerview.utils.JsonAsyncTask;
public class Ex01Activity extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener, Ex01Adapter.OnItemClickListener, Ex01Adapter.OnItemLongClickListener {
private RecyclerView mRecyclerView;
private List<Focus.Item> mList;
private Ex01Adapter mAdapter;
private RadioGroup mRadioGroup;
private RecyclerView.OnScrollListener mOnScrollListener;//滚动事件
private LinearLayoutManager mLm;
private StaggeredGridLayoutManager mSgm;
private GridLayoutManager mGm;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_ex01);
init();
loadData();//数据下载
}
private void loadData() {
new JsonAsyncTask(new JsonAsyncTask.Callback() {
@Override
public void sendData(byte[] json) {
try {
Focus focus = new Gson().fromJson(new String(json, "utf-8"), Focus.class);
mList.addAll(focus.getList());
mAdapter.notifyDataSetChanged();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
},this).execute(Ex01Url.URL);
}
private void init() {
mList = new ArrayList<>();
mAdapter = new Ex01Adapter(this,mList);
mRecyclerView = (RecyclerView)findViewById(R.id.recycler_view);
mRadioGroup = (RadioGroup)findViewById(R.id.rg);
mRadioGroup.setOnCheckedChangeListener(this);
//初始化布局管理器
mLm = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
mGm = new GridLayoutManager(this, 2, LinearLayoutManager.VERTICAL, false);
mGm.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
return position==0? 2:1;
}
});
mSgm = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);
mRecyclerView.setLayoutManager(mLm);
mRecyclerView.setAdapter(mAdapter);
mAdapter.setOnClickListener(this);//adapter传过来的点击事件
mAdapter.setOnLongClickListener(this);//adapter传过来的长按事件
mRecyclerView.setItemAnimator(new DefaultItemAnimator());//设置默认动画
//!!!滚动事件是内部类，java不支持多继承，所以要自己创建类对象再添加相应方法
mOnScrollListener = new RecyclerView.OnScrollListener(){
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
}
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
if (newState == RecyclerView.SCROLL_STATE_IDLE) {//!!!必须监听状态停止不然会刷新多次
int position = mLm.findLastVisibleItemPosition();//!!!布局管理器才能得到Item的当前位置关系，RecyclerView没有监听Item变化的
if (position == mList.size() - 1) {
Toast.makeText(Ex01Activity.this, "刷新成功", Toast.LENGTH_SHORT).show();
loadData();
}
}
}
};
mRecyclerView.addOnScrollListener(mOnScrollListener);//初始化后再添加滚动方法
}
@Override
public void onCheckedChanged(RadioGroup group, int checkedId) {
switch (checkedId) {
case R.id.rb_01://线性布局管理
mRecyclerView.setLayoutManager(mLm);//改变成线性布局
break;
case R.id.rb_02://网格布局管理
mRecyclerView.setLayoutManager(mGm);//改变成网格布局
break;
case R.id.rb_03://稀疏布局管理(瀑布流)
mRecyclerView.setLayoutManager(mSgm);//改变成稀疏布局
break;
}
}
@Override
public void MyItemClick(RecyclerView recyclerView, View v, int position, Focus.Item data) {
Toast.makeText(this, "当前"+position +data.getTitle(), Toast.LENGTH_SHORT).show();
}
@Override
public void MyItemLongClick(RecyclerView recyclerView, View v, int position, Focus.Item data) {
Toast.makeText(this, "当前长按"+position +data.getTitle(), Toast.LENGTH_SHORT).show();
mList.remove(position);
mAdapter.notifyItemChanged(position);
if (position != mList.size()-1) {
mAdapter.notifyItemRangeChanged(position,mList.size()-position);
}
}
}
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