android 5.0新特性学习--RecyclerView

在过去很多年，我们的PC或者手机设备都是采用拟物化的设计风格，IOS采用扁平化的特性，android在2014年IO大会上说采用Material Design的设计风格，显示效果不能过于生硬的转换，而是平滑，过度的切换方式，避免线性的动画效果，而是代替以曲线的效果进行展示，并且所有的图标的动画切换都应该无缝化切换。

如果想深入了解材料设计即（material Design）的设计：

可以参看如下网址：http://design.1sters.com，尤其是android 应用的UED设计师们，可以看下：

开发中要在libs文件夹下面中加上android_support_v4.jar包

RecyclerView

java.lang.Object
　　android.view.View
　　　　android.view.ViewGroup
　　　　　　android.support.v7.widget.RecyclerView

官网地址：https://developer.android.com/reference/android/support/v7/widget/RecyclerView.html

RecyclerView 一个特点就是，将 layout 抽象成了一个 LayoutManager，RecylerView 不负责子 View 的布局， 我们可以自定义 LayoutManager 来实现不同的布局效果， 目前只提供了LinearLayoutManager。 LinearLayoutManager 可以指定方向，默认是垂直， 可以指定水平， 这样就轻松实现了水平的 ListView。

除了LinearLayoutManager还有其他两种布局管理器：

GridLayoutManager 网格的item
StaggeredGridLayoutManager 交错的网格item

当然也可以通过集成ResyclerView,layoutManager类来自定义自己的布局管理器。

RecyclerView的使用过程中会使用到一个Adapter:RecyclerView.Adapter，里面屏蔽了以前写BaseAdapter的中好多重读的代码的编写，将加载item布局放在onCreateViewHolder（ViewGroup viewGroup, int i）方法中，在onBindViewHolder(ViewHolder viewHolder, int i)中数据加载到item中。用于优化的viewHolder也是继承自RecyclerView.ViewHolder。

RecyclerView不提供setOnItemClickListener方法，你可以在ViewHolder中添加事件。

RecyclerView之间的分割线：

http://my.oschina.net/xesam/blog/351408

官网地址：https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter.html

关于使用可以参考：

http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2014/0710/1631.html

http://blog.csdn.net/cym492224103/article/details/41719497

编写demo:

布局文件：

activity_main.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:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.wangfubin.recyclerview.MainActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/id_recyclerview"
        android:divider="#ffff0000"
        android:dividerHeight="10dp"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</RelativeLayout>

item_gridview.xml:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="100dp"
    xmlns:tool="http://schemas.android.com/tools"
    android:background="#44ff0000"
    android:layout_height="100dp">

    <TextView
        android:id="@+id/id_num"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:gravity="center"
        tool:text="1" />
</FrameLayout>

item_listview.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    xmlns:tool="http://schemas.android.com/tools"
    android:background="#44ff0000"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/id_num"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:gravity="center"
        tool:text="1" />
</FrameLayout>

MainActivity.java

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
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 MainActivity extends AppCompatActivity {

    private RecyclerView mRecyclerView;
    private List<String> mDatas;
    private HomeAdapter mAdapter;

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

        initData();
        mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerview);
        //垂直线性RecyclerView
        //mRecyclerView.setLayoutManager(new LinearLayoutManager(this));

        //Grid布局
        //mRecyclerView.setLayoutManager(new GridLayoutManager(this,4));

        //瀑布流
        //垂直方向
        //mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.VERTICAL));
        //水平方向
        mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.HORIZONTAL));

        mRecyclerView.setAdapter(mAdapter = new HomeAdapter(getApplicationContext(),initData()));
        //垂直线性RecyclerView分割线
        //mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST));

        //GridView的分隔线
        mRecyclerView.addItemDecoration(new DividerGridItemDecoration(this));
        //添加默认动画
        mRecyclerView.setItemAnimator(new DefaultItemAnimator());
        mAdapter.setOnItemClickLitener(new HomeAdapter.OnItemClickLitener() {
            @Override
            public void onItemClick(View view, int position) {
                Toast.makeText(getApplicationContext(),"单击事件",Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onItemLongClick(View view, int position) {
                Toast.makeText(getApplicationContext(),"长按事件",Toast.LENGTH_SHORT).show();
            }
        });

    }

    /**
     * 初始化模拟数据
     * @return
     */
    protected List<String> initData() {
        mDatas = new ArrayList<String>();
        for (int i = 'A'; i < 'z'; i++) {
            mDatas.add("" + (char) i);
        }
        return mDatas;
    }

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

    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        switch (item.getItemId())
        {

            case R.id.id_action_add:
                //新增数据
                mAdapter.addData(1);
                break;
            case R.id.id_action_delete:
                //删除数据
                mAdapter.removeData(1);
                break;
        }
        return true;
    }

}

HomeAdapter.java

import java.util.List;

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

/**
 * Created by wangfubin on 2016/11/12.
 */

class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder>
{

    private List<String> mDatas;
    private LayoutInflater mInflater;

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

    private OnItemClickLitener mOnItemClickLitener;

    public void setOnItemClickLitener(OnItemClickLitener mOnItemClickLitener)
    {
        this.mOnItemClickLitener = mOnItemClickLitener;
    }

    public HomeAdapter(Context context, List<String> datas)
    {
        mInflater = LayoutInflater.from(context);
        mDatas = datas;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType)
    {
        MyViewHolder holder = new MyViewHolder(mInflater.inflate(
                R.layout.item_listview, parent, false));
        return holder;
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position)
    {
        holder.tv.setText(mDatas.get(position));

        // 如果设置了回调，则设置点击事件
        if (mOnItemClickLitener != null)
        {
            holder.itemView.setOnClickListener(new OnClickListener()
            {
                @Override
                public void onClick(View v)
                {
                    int pos = holder.getLayoutPosition();
                    mOnItemClickLitener.onItemClick(holder.itemView, pos);
                }
            });

            holder.itemView.setOnLongClickListener(new OnLongClickListener()
            {
                @Override
                public boolean onLongClick(View v)
                {
                    int pos = holder.getLayoutPosition();
                    mOnItemClickLitener.onItemLongClick(holder.itemView, pos);
                    removeData(pos);
                    return false;
                }
            });
        }
    }

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

    public void addData(int position)
    {
        mDatas.add(position, "Insert One");
        notifyItemInserted(position);
    }

    public void removeData(int position)
    {
        mDatas.remove(position);
        notifyItemRemoved(position);
    }

    class MyViewHolder extends ViewHolder
    {

        TextView tv;

        public MyViewHolder(View view)
        {
            super(view);
            tv = (TextView) view.findViewById(R.id.id_num);

        }
    }
}

DividerItemDecoration.java

/**
 * 垂直水平分割线
 */
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);
            android.support.v7.widget.RecyclerView v = new android.support.v7.widget.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();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

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

DividerGridItemDecoration.java

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.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.LayoutManager;
import android.support.v7.widget.RecyclerView.State;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.View;

/**
 *GridView分割线
 * @author zhy
 *
 */
public class DividerGridItemDecoration extends RecyclerView.ItemDecoration
{

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

    public DividerGridItemDecoration(Context context)
    {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, State state)
    {

        drawHorizontal(c, parent);
        drawVertical(c, parent);

    }

    private int getSpanCount(RecyclerView parent)
    {
        // 列数
        int spanCount = -1;
        LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager)
        {

            spanCount = ((GridLayoutManager) layoutManager).getSpanCount();
        } else if (layoutManager instanceof StaggeredGridLayoutManager)
        {
            spanCount = ((StaggeredGridLayoutManager) layoutManager)
                    .getSpanCount();
        }
        return spanCount;
    }

    public void drawHorizontal(Canvas c, RecyclerView parent)
    {
        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.getLeft() - params.leftMargin;
            final int right = child.getRight() + params.rightMargin
                    + mDivider.getIntrinsicWidth();
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    public void drawVertical(Canvas c, RecyclerView parent)
    {
        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 top = child.getTop() - params.topMargin;
            final int bottom = child.getBottom() + params.bottomMargin;
            final int left = child.getRight() + params.rightMargin;
            final int right = left + mDivider.getIntrinsicWidth();

            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    private boolean isLastColum(RecyclerView parent, int pos, int spanCount,
                                int childCount)
    {
        LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager)
        {
            if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
            {
                return true;
            }
        } else if (layoutManager instanceof StaggeredGridLayoutManager)
        {
            int orientation = ((StaggeredGridLayoutManager) layoutManager)
                    .getOrientation();
            if (orientation == StaggeredGridLayoutManager.VERTICAL)
            {
                if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
                {
                    return true;
                }
            } else
            {
                childCount = childCount - childCount % spanCount;
                if (pos >= childCount)// 如果是最后一列，则不需要绘制右边
                    return true;
            }
        }
        return false;
    }

    private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,
                              int childCount)
    {
        LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager)
        {
            childCount = childCount - childCount % spanCount;
            if (pos >= childCount)// 如果是最后一行，则不需要绘制底部
                return true;
        } else if (layoutManager instanceof StaggeredGridLayoutManager)
        {
            int orientation = ((StaggeredGridLayoutManager) layoutManager)
                    .getOrientation();
            // StaggeredGridLayoutManager 且纵向滚动
            if (orientation == StaggeredGridLayoutManager.VERTICAL)
            {
                childCount = childCount - childCount % spanCount;
                // 如果是最后一行，则不需要绘制底部
                if (pos >= childCount)
                    return true;
            } else
            // StaggeredGridLayoutManager 且横向滚动
            {
                // 如果是最后一行，则不需要绘制底部
                if ((pos + 1) % spanCount == 0)
                {
                    return true;
                }
            }
        }
        return false;
    }

    @Override
    public void getItemOffsets(Rect outRect, int itemPosition,
                               RecyclerView parent)
    {
        int spanCount = getSpanCount(parent);
        int childCount = parent.getAdapter().getItemCount();
        if (isLastRaw(parent, itemPosition, spanCount, childCount))// 如果是最后一行，则不需要绘制底部
        {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        } else if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最后一列，则不需要绘制右边
        {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else
        {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(),
                    mDivider.getIntrinsicHeight());
        }
    }
}

效果：