Android RecyclerView 获取数据实现添加，删除功能

RecyclerView出现已经有一段时间了，相信大家肯定不陌生了，大家可以通过导入support-v7对其进行使用。 

添加依赖：

compile 'com.android.support:recyclerview-v7:25.3.1'compile 'com.android.support:mediarouter-v7:25.3.1'compile 'com.jakewharton:butterknife:7.0.1'

Just like ListView
Activity的布局文件
<?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.qizu.recyclerview.MainActivity">    <LinearLayout        android:id="@+id/LL"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="horizontal">        <Button            android:text="添加"            android:onClick="add"            android:id="@+id/adds"            android:layout_width="wrap_content"            android:layout_height="wrap_content" />        <Button            android:text="删除"            android:id="@+id/deletes"            android:onClick="delete"            android:layout_width="wrap_content"            android:layout_height="wrap_content" />    </LinearLayout>    <android.support.v7.widget.RecyclerView        android:layout_below="@+id/LL"        android:id="@+id/id_recyclerview"        android:divider="#ff00ff"        android:dividerHeight="10dp"        android:layout_width="match_parent"        android:layout_height="match_parent"/></RelativeLayout>
Item_home的布局文件
<?xml version="1.0" encoding="utf-8"?><FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    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"        android:text="1" /></FrameLayout>

Activity
package com.qizu.recyclerview;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.DefaultItemAnimator;import android.support.v7.widget.DividerItemDecoration;import android.support.v7.widget.GridLayoutManager;import android.support.v7.widget.LinearLayoutManager;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 MainActivity extends AppCompatActivity {    private RecyclerView mRecyclerView;    private List<String> mDatas;    HomeAdapter homeAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initData(); //初始化数据        mRecyclerView = (RecyclerView) findViewById(R.id.id_recyclerview);        //mRecyclerView.setLayoutManager(new LinearLayoutManager(this)); //设置LinearLayoutManager布局管理器        //mRecyclerView.setLayoutManager(new GridLayoutManager(this,4));//设置GridLayoutManager布局管理器        mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(4,StaggeredGridLayoutManager.VERTICAL));//设置StaggeredGridLayoutManager纵向布局管理器        //mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(4,StaggeredGridLayoutManager.HORIZONTAL));//设置StaggeredGridLayoutManager横向布局管理器(修改item布局就可以控制大小)        homeAdapter = new HomeAdapter(MainActivity.this, (ArrayList<String>) mDatas);        mRecyclerView.setAdapter(homeAdapter);  // 设置适配器        //mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL)); // 设置默认分割线        mRecyclerView.addItemDecoration(new com.qizu.recyclerview.DividerItemDecoration(this, com.qizu.recyclerview.DividerItemDecoration.HORIZONTAL_LIST));//自定义纵向分割线        mRecyclerView.addItemDecoration(new com.qizu.recyclerview.DividerItemDecoration(this, com.qizu.recyclerview.DividerItemDecoration.VERTICAL_LIST));// 自定义横向分割线        // 设置item动画        mRecyclerView.setItemAnimator(new DefaultItemAnimator());        //设置点击事件 (接口回调)        homeAdapter.setOnItemClickLitener(new HomeAdapter.OnItemClickLitener() {            @Override            //点击吐司            public void onItemClick(View view, int position) {                Toast.makeText(MainActivity.this, position + " click", Toast.LENGTH_SHORT).show();            }            //长按吐司删除            @Override            public void onItemLongClick(View view, int position) {                Toast.makeText(MainActivity.this, position + " long click", Toast.LENGTH_SHORT).show();                homeAdapter.removeData(position);            }        });    }    // 初始化数据    private void initData() {        mDatas = new ArrayList<String>();        for (int i = 0; i < 101; i++) {            mDatas.add("Zhangren" + i);        }    }    //添加    public void add(View v){        homeAdapter.addData(1);    }    //删除    public void delete(View v){        homeAdapter.removeData(1);    }}
HomeAdapter
package com.qizu.recyclerview;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.AdapterView;import android.widget.TextView;import java.util.ArrayList;import java.util.List;public class HomeAdapter extends RecyclerView.Adapter<HomeAdapter.MyViewHolder> {    private Context context;    private List<Integer> datas;    private ArrayList<String> mDatas;    private OnItemClickLitener mOnItemClickLitener;  // 监听     /*item的点击事件的长按事件接口*/     private AdapterView.OnItemClickListener onItemClickListener;    /*瀑布流时的item随机高度*/    private List<Integer> heights = new ArrayList<>();    /*不同的类型设置item不同的高度*/    private int type = 0;    public HomeAdapter(Context context, List<Integer> datas) {        this.context = context;        this.datas = datas;        for (int i : datas) {            int height = (int) (Math.random() * 100 + 300);            heights.add(height);        }    }    public void setType(int type) {        this.type = type;    }    /**     * 设置点击事件     *     * @param onItemClickListener     */    //定义接口    public interface OnItemClickLitener {        void onItemClick(View view, int position);        void onItemLongClick(View view, int position);    }    public void setOnItemClickLitener(OnItemClickLitener mOnItemClickLitener) {        this.mOnItemClickLitener = mOnItemClickLitener;    }    //构造方法    public HomeAdapter(Context context, ArrayList<String> mDatas) {        this.context = context;        this.mDatas = mDatas;    }    // 实例化 Holder    @Override    public HomeAdapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        MyViewHolder holder = new MyViewHolder(LayoutInflater.from(context).inflate(R.layout.item_home, parent, false));        return holder;    }    //绑定holder  在onBindHolder中 设置数据    @Override    public void onBindViewHolder(final HomeAdapter.MyViewHolder holder, 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 View.OnClickListener() {                @Override                public void onClick(View v) {                    int pos = holder.getLayoutPosition();                    mOnItemClickLitener.onItemClick(holder.itemView, pos);                }            });            holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {                @Override                public boolean onLongClick(View v) {                    int pos = holder.getLayoutPosition();                    mOnItemClickLitener.onItemLongClick(holder.itemView, pos);                    return false;                }            });        }    }    // 总条数    @Override    public int getItemCount() {        return mDatas.size();    }    // 在 holder中 找到控件    public class MyViewHolder extends RecyclerView.ViewHolder {        TextView tv;        public MyViewHolder(View view) {            super(view);            tv = (TextView) view.findViewById(R.id.id_num);        }    }    /**     * 设置item监听的接口     */    public interface OnItemClickListener {        void onItemClickListener(int position, Integer data);    }    //添加更新数据    public void addData(int position) {        mDatas.add(position, "Zhangren");        notifyItemInserted(position);    }    //删除更新数据    public void removeData(int position) {        mDatas.remove(position);        notifyItemRemoved(position);    }}
ItemDecoration
我们可以通过该方法添加分割线： 
mRecyclerView.addItemDecoration() 该类参考自：DividerItemDecoration
package com.qizu.recyclerview;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.view.View;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);        }    }    /**     * 绘制纵向列表时的分隔线  这时分隔线是横着的     * 每次 left相同，top根据child变化，right相同，bottom也变化     * @param c     * @param 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);        }    }    /**     * 绘制横向列表时的分隔线  这时分隔线是竖着的     * l、r 变化； t、b 不变     * @param c     * @param parent     */    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);        }    }}

该分割线是系统默认的，你可以在theme.xml中找到该属性的使用情况。那么，使用系统的listDivider有什么好处呢？就是方便我们去随意的改变，该属性我们可以直接声明在：
 <!-- Application theme. -->    <style name="AppTheme" parent="AppBaseTheme">      <item name="android:listDivider">@drawable/divider_bg</item>      </style>
1
2
3
4
然后自己写个drawable即可，下面我们换一种分隔符：
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android"    android:shape="rectangle" >    <gradient        android:centerColor="#ff00ff00"        android:endColor="#ff0000ff"        android:startColor="#ffff0000"        android:type="linear" />    <size android:height="4dp"/></shape>
我们尝试去实现类似GridView，秒秒钟的事情：
//mRecyclerView.setLayoutManager(new LinearLayoutManager(this));        mRecyclerView.setLayoutManager(new GridLayoutManager(this,4));
1
2
针对上述，我们编写了DividerGridItemDecoration。

package com.qizu.recyclerview;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;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) {        RecyclerView.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) {        RecyclerView.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());        }    }}

Hongyang
大神的博客出处：    
http://blog.csdn.net/lmj623565791/article/details/45059587；