RecyclerView的使用

    周末看了Recylerview的使用，RecyclerView在android标准的sdk中并没有收录，如果使用的话需要导入android.support.v7.widget.RecyclerView 这个包，这个view当中包含了一个ViewHolder相当于listview的升级版本，它所解决的问题就是itemview的复用，它并不关心怎样去显示。这其实是完全脱耦合的一种架构思想，布局的显示方式可以通过  **recyclerView.setLayoutManager（LayoutManager）**来设置，备选的方案有很多，可以设置横向listview、纵向listview、以及横纵向的gridview方式，甚至支持瀑布流的方式显示。但是这个控件本身并没有分割线，需要开发者自己去手动添加 **recyclerView.addItemDecoration(dividerItemDecoration)**这个即是添加分割线。**recyclerView.setItemAnimator( new DefaultItemAnimator())**这个是添加默认动画的。可以看到这个控件除了提供一个viewHolder之外什么都没有，需要什么你就自己去添加什么。下面就贴代码了：

activity_simple_recycler.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.mhyuam.reccler.SimpleRecyclerActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />
</RelativeLayout>

layout_item.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    android:padding="2dp">
    <TextView
        android:id="@+id/item_tv"
        android:gravity="center"
        android:background="@drawable/item_bg"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:textSize0sp" 

    />
</FrameLayout>

这里写代码片

import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
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.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;

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


public class SimpleRecyclerActivity extends ActionBarActivity {

    RecyclerView recyclerView;
    LinearLayoutManager horizontalManager;
    LinearLayoutManager vercitalManager;
    GridLayoutManager verticalGridManager;
    GridLayoutManager horiziontalGridManager;
    DividerItemDecoration dividerItemDecoration;
    SimpleItemAdapter adapter;

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

    private void init(){
        recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
        horizontalManager = new LinearLayoutManager(SimpleRecyclerActivity.this,LinearLayoutManager.HORIZONTAL,false);
        vercitalManager = new LinearLayoutManager(SimpleRecyclerActivity.this,LinearLayoutManager.VERTICAL,false);
        verticalGridManager = new GridLayoutManager(SimpleRecyclerActivity.this,3,GridLayoutManager.VERTICAL,false);
        horiziontalGridManager = new GridLayoutManager(SimpleRecyclerActivity.this,5,GridLayoutManager.HORIZONTAL,false);
        List<String> datas = new ArrayList<String>();
        for (int i = 0; i < 200; i++){
            datas.add(i+"");
        }

        adapter = new SimpleItemAdapter(SimpleRecyclerActivity.this,datas);
        adapter.setOnItemClickListener(new SimpleItemAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                Toast.makeText(SimpleRecyclerActivity.this,"onclick: "+position,Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onItemLongClick(View view, int position) {
                Toast.makeText(SimpleRecyclerActivity.this,"onlongclick: "+position,Toast.LENGTH_SHORT).show();
            }
        });
        recyclerView.setAdapter(adapter);
        recyclerView.setItemAnimator( new DefaultItemAnimator());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.options_menu,menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        return setSelectItemLayout(item);
    }


    private boolean setSelectItemLayout(MenuItem item){

        switch (item.getItemId()){
            case R.id.action_add:
                adapter.addItem("one");
                return true;
            case R.id.action_delete:
                adapter.deleteItem();
                return true;
            case R.id.action_horizontal:
                recyclerView.setLayoutManager(horizontalManager);
                return true;
            case R.id.action_verictal:
                recyclerView.setLayoutManager(vercitalManager);
                return true;
            case R.id.action_grid_hor:
                recyclerView.setLayoutManager(horiziontalGridManager);
                return true;
            case R.id.action_grid_ver:
                recyclerView.setLayoutManager(verticalGridManager);
                return true;
            case R.id.action_stroggle:
                Intent intent = new Intent(this,WaterfallActivity.class);
                startActivity(intent);
                return true;
            default:

                return false;
        }
    }

}

SimpleItemAdapter

package com.example.mhyuam.reccler;

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

import java.util.List;

/**
 * Created by mhyuam on 2016/7/16.
 */
public class SimpleItemAdapter extends RecyclerView.Adapter<SimpleItemAdapter.MyHolder> {

    private List<String> datas;
    private LayoutInflater inflater;
    private Context context;
    private OnItemClickListener itemClickListener;

    public SimpleItemAdapter(Context context, List list) {
        datas = list;
        this.context = context;
        inflater = LayoutInflater.from(context);
    }

    public void setOnItemClickListener(OnItemClickListener itemClickListener){
        this.itemClickListener = itemClickListener;
    }
    @Override
    public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.layout_item,parent,false);
        MyHolder holder = new MyHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(final MyHolder holder, int position) {
        holder.textView.setText(datas.get(position).toString());
        if (itemClickListener != null){
            holder.textView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    int pos = holder.getLayoutPosition();
                    itemClickListener.onItemClick(holder.textView,pos);
                }
            });
            holder.textView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    int pos = holder.getLayoutPosition();
                    itemClickListener.onItemLongClick(holder.textView,pos);
                    return false;
                }
            });
        }

    }

   public void addItem(String string){
        datas.add(1,string);
       notifyItemInserted(1);
      notifyItemRemoved(1);
    }


    @Override
    public int get  }

    public void deleteItem(){
        datas.remove(1);
   ItemCount() {
        return datas.size();
    }


    public interface OnItemClickListener {
        public void onItemClick(View view,int position);
        public void onItemLongClick(View view,int position);
    }

   public static class MyHolder extends RecyclerView.ViewHolder{
        TextView textView;
        public MyHolder(ViewetemView) {
            super(itemView);
            textView = xtV ew) itemView.findViewById(R.id.item_tv);
        }
    }
}

DividerItemDe中复该属性，以达到定制分割线的目的，定制时同时注意放置style的values-xx,如果没有和该版本对应得values，默认是从上往下取值

package com.example.mhyuam.reccler;

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;

/**
 * This class is from the v7 samples of the Android SDK. It‘s not by me!
 * <p/>
 * See the license above for details.
 */
public class DividerItemDecoration extends RecyclerView.ItemDecoration
{

    private static final int[] ATTRS = new int[] { android.R.attr.listDivider };

    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;



    private Drawable mDivider;

    private int mOrientation;

    public DividerItemDecoration(Context context, int orientation)
    {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
        setOrientation(orientation);
    }

    public void setOrientation(int orientation)
    {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST)
        {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent)
    {
        //Log.v("recyclerview - itemdecoration", "onDraw()");
         if (mOrientation == VERTICAL_LIST) {
                drawVertical(c, parent);
            } else {
                drawHorizontal(c, parent);
            }
    }

    public void drawVertical(Canvas c, RecyclerView parent)
    {
        final int left = parent.getPaddingLeft();
        final int right = parent.getWidth() - parent.getPaddingRight();

        final int childCount = parent.getChildCount();

        for (int i = 0; i < childCount; i++)
        {
            final View child = parent.getChildAt(i);
            RecyclerView v = new RecyclerView(
                    parent.getContext());
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    public void drawHorizontal(Canvas c, RecyclerView parent)
    {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getHeight() - parent.getPaddingBottom();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++)
        {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int left = child.getRight() + params.rightMargin;
            final int right = left + mDivider.getIntrinsicHeight();
            mDivi`
der.setBounds(leftSright, bottom);
            mDivider.draw(c);
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, int itemPosition,
            RecyclerView parent)
    {
`
    if (mOrieT)
        {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else
        {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        }
    }
}

下面是瀑布流的实现

package com.example.mhyuam.reccler;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.View;
import android.widget.Toast;

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


public class WaterfallActivity extends ActionBarActivity {

    RecyclerView recyclerView;

    DividerItemDecoration dividerItemDecoration;//分割线
    StaggeredGridLayoutManager staggeredGridLayoutManager;
    WaterfallAdapter adapter;

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

    private void init(){
        recyclerView = (RecyclerView) findViewById(R.id.recyclerview);

        List<String> datas = new ArrayList<String>();
        for (int i = 0; i < 200; i++){
            datas.add(i+"");
        }

        adapter = new WaterfallAdapter(WaterfallActivity.this,datas);
        adapter.setOnItemClickListener(new WaterfallAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                Toast.makeText(WaterfallActivity.this,"onclick: "+position,Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onItemLongClick(View view, int position) {
                Toast.makeText(WaterfallActivity.this,"onlongclick: "+position,Toast.LENGTH_SHORT).show();
            }
        });
        dividerItemDecoration = new DividerItemDecoration(WaterfallActivity.this,StaggeredGridLayoutManager.VERTICAL);
        staggeredGridLayoutManager = new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL);
        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(staggeredGridLayoutManager);
        /**
         * 设置分割线，分割线的样式有android.R.attr.listDivider决定，
         * 可以在style中复写该属性，以达到定制分割线的目的
         * 定制时同时注意放置style的values-xx,如果没有和该版本对应得values，默认是从上往下取值
         */
        recyclerView.addItemDecoration(dividerItemDecoration);
        /**
         * 设置item变动时的动画
         */
        recyclerView.setItemAnimator( new DefaultItemAnimator());
    }

}

package com.example.mhyuam.reccler;

import android.content.Context;
import android.support.annotation.Nullable;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

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

/**
 * Created by mhyuam on 2016/7/16.
 */
public class WaterfallAdapter extends RecyclerView.Adapter<WaterfallAdapter.MyHolder> {

    private List<String> datas;
    private LayoutInflater inflater;
    private Context context;
    private OnItemClickListener itemClickListener;
    private List<Integer> height;

    public WaterfallAdapter(Context context, List list) {
        datas = list;
        this.context = context;
        inflater = LayoutInflater.from(context);
        height = new ArrayList<Integer>();
        for (int i = 0; i < datas.size();i++){
            height.add((int)( 200 + Math.random()*200));
        }
    }

    public void setOnItemClickListener(OnItemClickListener itemClickListener){
        this.itemClickListener = itemClickListener;
    }
    @Override
    public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = inflater.inflate(R.layout.layout_item,parent,false);
        MyHolder holder = new MyHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(final MyHolder holder, int position) {
        holder.textView.setText(datas.get(position).toString());
        ViewGroup.LayoutParams lp = holder.textView.getLayoutParams();
        lp.height = height.get(position);
        holder.textView.setLayoutParams(lp);
        if (itemClickListener != null){
            holder.textView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    /**
                     * pos取值时需要注意，由于在add和delete item时会引起位置信息的变动
                     * 这里一定要动态去获取当前item在整个布局中的位置
                     */
                    int pos = holder.getLayoutPosition();
                    itemClickListener.onItemClick(holder.textView,pos);
                }
            });
            holder.textView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    int pos = holder.getLayoutPosition();
                    itemClickListener.onItemLongClick(holder.textView,pos);
                    return false;
                }
            });
        }

    }

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


    public interface OnItemClickListener {
        public void onItemClick(View view,int position);
        public void onItemLongClick(View view,int position);
    }

    public static class MyHolder extends RecyclerView.ViewHolder{
        TextView textView;
        public MyHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView.findViewById(R.id.item_tv);
        }
    }
}