RecyclerView简单使用

 1.  在build.gradle(Module)的dependency(dependencies)添加引用：

          compile ‘com.android.support:recyclerview-v7:25.3.1

  2. 在布局中添加recyclerview

<android.support.v7.widget.RecyclerView
     android:id="@+id/recyclerview"    
     android:layout_width="match_parent"    
     android:layout_height="match_parent"    
     android:background="@android:color/darker_gray"    
     android:visibility="gone"    
     android:fadeScrollbars="true"    
     android:scrollbars="vertical">
   </android.support.v7.widget.RecyclerView>

3. 创建recyclerView的Adapter

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
    private ArrayList<String> mData;
    public MyAdapter(ArrayList<String> data) {
        this.mData = data;
    }

    public void addNewItem() {
        if(mData == null) {
            mData = new ArrayList<>();
        }
        int size=mData.size();
        mData.add(size, size+" Item");
        notifyItemInserted(size);
    }

    public void deleteItem() {
        if(mData == null || mData.isEmpty()) {
            return;
        }
        int size=mData.size();
        mData.remove(size-1);
        notifyItemRemoved(size-1);
    }

    public void updateData(ArrayList<String> data) {
        this.mData = data;
        notifyDataSetChanged();
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        // 实例化展示的view
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_rv_item, parent, false);
        // 实例化viewholder
        ViewHolder viewHolder = new ViewHolder(v);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        // 绑定数据
        holder.mTv.setText(mData.get(position));
    }

    @Override
    public int getItemCount() {
        return mData == null ? 0 : mData.size();
    }

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

public class MyStaggeredRvAdapter extends RecyclerView.Adapter<MyStaggeredRvAdapter.ViewHolder> {
    /**
     * 展示数据
     */
    private ArrayList<String> mData;

    public MyStaggeredRvAdapter(ArrayList<String> data) {
        this.mData = data;
    }

    public void updateData(ArrayList<String> data) {
        this.mData = data;
        notifyDataSetChanged();
    }

    @Override
    public int getItemViewType(int position) {
        // 瀑布流样式外部设置spanCount为3，在这列设置三个不同的item type，以区分不同的布局
        return position % 3;
    }

    @Override
    public MyStaggeredRvAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        // 实例化展示的view
        View v;
        if(viewType == 1) {
            v = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_rv_staggered_item, parent, false);
        } else if (viewType==2){
            v = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_rv_staggered_item_three, parent, false);
        }else {
            v = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_rv_staggered_item_two, parent, false);
        }
        // 实例化viewholder
        ViewHolder viewHolder = new ViewHolder(v);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(MyStaggeredRvAdapter.ViewHolder holder, int position) {
        // 绑定数据
        holder.mTv.setText(mData.get(position));
    }

    @Override
    public int getItemCount() {
        return mData == null ? 0 : mData.size();
    }

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

4. RecyclerView的item直接的间隔设置（自己定义）

// 线性recyclerview 的分组装饰（间隔）
public class MyDividerItemDecoration 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;
    /**
     * 用于绘制间隔样式
     */
    private Drawable mDivider;
    /**
     * 列表的方向，水平/竖直
     */
    private int mOrientation;

    private int mGroupHeight=40,mLeftMargin=10;
    private Paint mGroutPaint,mTextPaint;
    private MainActivity.GroupListener groupListener;

    public void setGroupListener(MainActivity.GroupListener groupListener) {
        this.groupListener = groupListener;
    }

    private boolean isFirstInGroup(int position){
        if (position==0){
            return true;
        }else {
            String prevGroupId = groupListener.getGroupName(position - 1);
            String groupId = groupListener.getGroupName(position);
            return !TextUtils.equals(prevGroupId,groupId);
        }
    }

    public MyDividerItemDecoration(Context context, int orientation) {
        // 获取默认主题的属性
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
        setOrientation(orientation);
        mGroutPaint=new Paint();
        mGroutPaint.setColor(0xFF41C2F9);
        mGroutPaint.setStyle(Paint.Style.FILL);
        mTextPaint=new Paint();
        mTextPaint.setStyle(Paint.Style.FILL);
        mTextPaint.setColor(0xffffffff);
        mTextPaint.setTextSize(20.0f);
        mTextPaint.setStrokeWidth(5);
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        // 绘制间隔
//        if (mOrientation == VERTICAL_LIST) {
//            drawVertical(c, parent);
//        } else {
//            drawHorizontal(c, parent);
//        }
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
//        if (mOrientation == VERTICAL_LIST) {
//            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
//        } else {
//            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
//        }

        int pos = parent.getChildAdapterPosition(view);
        String groupId = groupListener.getGroupName(pos);
        if (groupId == null) return;
        //只有是同一组的第一个才显示悬浮栏
        if (pos == 0 || isFirstInGroup(pos)) {
            outRect.top = mGroupHeight;
        }
    }

    @Override
    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        super.onDrawOver(c, parent, state);
        final int itemCount = state.getItemCount();
        final int childCount = parent.getChildCount();
        final int left = parent.getLeft() + parent.getPaddingLeft();
        final int right = parent.getRight() - parent.getPaddingRight();
        String preGroupName;      //标记上一个item对应的Group
        String currentGroupName = null;       //当前item对应的Group
        for (int i = 0; i < childCount; i++) {
            View view = parent.getChildAt(i);
            int position = parent.getChildAdapterPosition(view);
            preGroupName = currentGroupName;
            currentGroupName = groupListener.getGroupName(position);
            if (currentGroupName == null || TextUtils.equals(currentGroupName, preGroupName))
                continue;
            int viewBottom = view.getBottom();
            float top = Math.max(mGroupHeight, view.getTop());//top 决定当前顶部第一个悬浮Group的位置
            if (position + 1 < itemCount) {
                //获取下个GroupName
                String nextGroupName = groupListener.getGroupName(position + 1);
                //下一组的第一个View接近头部
                if (!currentGroupName.equals(nextGroupName) && viewBottom < top) {
                    top = viewBottom;
                }
            }
            //根据top绘制group
            c.drawRect(left, top - mGroupHeight, right, top, mGroutPaint);
            Paint.FontMetrics fm = mTextPaint.getFontMetrics();
            //文字竖直居中显示
            float baseLine = top - (mGroupHeight - (fm.bottom - fm.top)) / 2 - fm.bottom;
            c.drawText(currentGroupName, left + mLeftMargin, baseLine, mTextPaint);
        }
    }

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

    /**
     * 绘制间隔
     */
    private 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);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int top = child.getBottom() + params.bottomMargin +
                    Math.round(ViewCompat.getTranslationY(child));
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    /**
     * 绘制间隔
     */
    private 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 +
                    Math.round(ViewCompat.getTranslationX(child));
            final int right = left + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }
}

//表格类型的Recyclerview的间隔线装饰

public class MyGridRvDividerDecoration extends RecyclerView.ItemDecoration {
    private static final int[] ATTRS = new int[]{android.R.attr.listDivider};

    /**
     * 用于绘制间隔样式
     */
    private Drawable mDivider;

    public MyGridRvDividerDecoration(Context context) {
        // 获取默认主题的属性
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
    }


    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        // 绘制间隔，每一个item，绘制右边和下方间隔样式
        int childCount = parent.getChildCount();
        int spanCount = ((GridLayoutManager)parent.getLayoutManager()).getSpanCount();
        int orientation = ((GridLayoutManager)parent.getLayoutManager()).getOrientation();
        boolean isDrawHorizontalDivider = true;
        boolean isDrawVerticalDivider = true;
        int extra = childCount % spanCount;
        extra = extra == 0 ? spanCount : extra;
        for(int i = 0; i < childCount; i++) {
            isDrawVerticalDivider = true;
            isDrawHorizontalDivider = true;
            // 如果是竖直方向，最右边一列不绘制竖直方向的间隔
            if(orientation == OrientationHelper.VERTICAL && (i + 1) % spanCount == 0) {
                isDrawVerticalDivider = false;
            }

            // 如果是竖直方向，最后一行不绘制水平方向间隔
            if(orientation == OrientationHelper.VERTICAL && i >= childCount - extra) {
                isDrawHorizontalDivider = false;
            }

            // 如果是水平方向，最下面一行不绘制水平方向的间隔
            if(orientation == OrientationHelper.HORIZONTAL && (i + 1) % spanCount == 0) {
                isDrawHorizontalDivider = false;
            }

            // 如果是水平方向，最后一列不绘制竖直方向间隔
            if(orientation == OrientationHelper.HORIZONTAL && i >= childCount - extra) {
                isDrawVerticalDivider = false;
            }

            if(isDrawHorizontalDivider) {
                drawHorizontalDivider(c, parent, i);
            }

            if(isDrawVerticalDivider) {
                drawVerticalDivider(c, parent, i);
            }
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        int spanCount = ((GridLayoutManager) parent.getLayoutManager()).getSpanCount();
        int orientation = ((GridLayoutManager)parent.getLayoutManager()).getOrientation();
        int position = parent.getChildLayoutPosition(view);
        if(orientation == OrientationHelper.VERTICAL && (position + 1) % spanCount == 0) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
            return;
        }

        if(orientation == OrientationHelper.HORIZONTAL && (position + 1) % spanCount == 0) {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
            return;
        }
        outRect.set(0, 0, mDivider.getIntrinsicWidth(), mDivider.getIntrinsicHeight());
    }

    /**
     * 绘制竖直间隔线
     *
     * @param canvas
     * @param parent 父布局，RecyclerView
     * @param position item在父布局中所在的位置
     */
    private void drawVerticalDivider(Canvas canvas, RecyclerView parent, int position) {
        final View child = parent.getChildAt(position);
        final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                .getLayoutParams();
        final int top = child.getTop() - params.topMargin;
        final int bottom = child.getBottom() + params.bottomMargin + mDivider.getIntrinsicHeight();
        final int left = child.getRight() + params.rightMargin;
        final int right = left + mDivider.getIntrinsicWidth();
        mDivider.setBounds(left, top, right, bottom);
        mDivider.draw(canvas);
    }

    /**
     * 绘制水平间隔线
     *
     * @param canvas
     * @param parent
     *              父布局，RecyclerView
     * @param position
     *              item在父布局中所在的位置
     */
    private void drawHorizontalDivider(Canvas canvas, RecyclerView parent, int position) {
        final View child = parent.getChildAt(position);
        final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                .getLayoutParams();
        final int top = child.getBottom() + params.bottomMargin;
        final int bottom = top + mDivider.getIntrinsicHeight();
        final int left = child.getLeft() - params.leftMargin;
        final int right = child.getRight() + params.rightMargin + mDivider.getIntrinsicWidth();
        mDivider.setBounds(left, top, right, bottom);
        mDivider.draw(canvas);
    }
}

// 瀑布流的Recyclerview的间隔线装饰

public class MyStaggeredRvDividerDecotation extends RecyclerView.ItemDecoration{
    private static final int[] ATTRS = new int[]{android.R.attr.listDivider};

    /**
     * 用于绘制间隔样式
     */
    private Drawable mDivider;

    public MyStaggeredRvDividerDecotation(Context context) {
        // 获取默认主题的属性
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
    }


    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        // 绘制间隔，每一个item，绘制右边和下方间隔样式
        int childCount = parent.getChildCount();
        int spanCount = ((StaggeredGridLayoutManager)parent.getLayoutManager()).getSpanCount();
        int orientation = ((StaggeredGridLayoutManager)parent.getLayoutManager()).getOrientation();
        boolean isDrawHorizontalDivider = true;
        boolean isDrawVerticalDivider = true;
        int extra = childCount % spanCount;
        extra = extra == 0 ? spanCount : extra;
        for(int i = 0; i < childCount; i++) {
            isDrawVerticalDivider = true;
            isDrawHorizontalDivider = true;
            // 如果是竖直方向，最右边一列不绘制竖直方向的间隔
            if(orientation == OrientationHelper.VERTICAL && (i + 1) % spanCount == 0) {
                isDrawVerticalDivider = false;
            }

            // 如果是竖直方向，最后一行不绘制水平方向间隔
            if(orientation == OrientationHelper.VERTICAL && i >= childCount - extra) {
                isDrawHorizontalDivider = false;
            }

            // 如果是水平方向，最下面一行不绘制水平方向的间隔
            if(orientation == OrientationHelper.HORIZONTAL && (i + 1) % spanCount == 0) {
                isDrawHorizontalDivider = false;
            }

            // 如果是水平方向，最后一列不绘制竖直方向间隔
            if(orientation == OrientationHelper.HORIZONTAL && i >= childCount - extra) {
                isDrawVerticalDivider = false;
            }

            if(isDrawHorizontalDivider) {
                drawHorizontalDivider(c, parent, i);
            }

            if(isDrawVerticalDivider) {
                drawVerticalDivider(c, parent, i);
            }
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        int spanCount = ((StaggeredGridLayoutManager) parent.getLayoutManager()).getSpanCount();
        int orientation = ((StaggeredGridLayoutManager)parent.getLayoutManager()).getOrientation();
        int position = parent.getChildLayoutPosition(view);
        if(orientation == OrientationHelper.VERTICAL && (position + 1) % spanCount == 0) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
            return;
        }

        if(orientation == OrientationHelper.HORIZONTAL && (position + 1) % spanCount == 0) {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
            return;
        }
        outRect.set(0, 0, mDivider.getIntrinsicWidth(), mDivider.getIntrinsicHeight());
    }

    /**
     * 绘制竖直间隔线
     *
     * @param canvas
     * @param parent 父布局，RecyclerView
     * @param position item在父布局中所在的位置
     */
    private void drawVerticalDivider(Canvas canvas, RecyclerView parent, int position) {
        final View child = parent.getChildAt(position);
        final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                .getLayoutParams();
        final int top = child.getTop() - params.topMargin;
        final int bottom = child.getBottom() + params.bottomMargin + mDivider.getIntrinsicHeight();
        final int left = child.getRight() + params.rightMargin;
        final int right = left + mDivider.getIntrinsicWidth();
        mDivider.setBounds(left, top, right, bottom);
        mDivider.draw(canvas);
    }

    /**
     * 绘制水平间隔线
     *
     * @param canvas
     * @param parent
     *              父布局，RecyclerView
     * @param position
     *              item在父布局中所在的位置
     */
    private void drawHorizontalDivider(Canvas canvas, RecyclerView parent, int position) {
        final View child = parent.getChildAt(position);
        final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                .getLayoutParams();
        final int top = child.getBottom() + params.bottomMargin;
        final int bottom = top + mDivider.getIntrinsicHeight();
        final int left = child.getLeft() - params.leftMargin;
        final int right = child.getRight() + params.rightMargin + mDivider.getIntrinsicWidth();
        mDivider.setBounds(left, top, right, bottom);
        mDivider.draw(canvas);
    }
}

5. 开始使用RecyclerView

private RecyclerView recyclerView;
    private RecyclerView.LayoutManager layoutManager;
    private MyAdapter adapter;
//    private MyStaggeredRvAdapter adapter;
    @TargetApi(Build.VERSION_CODES.M)
    private void init() {
        adapter=new MyAdapter(getData());
//        adapter=new MyStaggeredRvAdapter(getData());   // 瀑布流时使用的Adapter
        layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);   //线性类型的LayoutManager 显示ListView类似
//        layoutManager=new GridLayoutManager(this,3, OrientationHelper.VERTICAL,false);  //表格类型的LayoutManager 显示GridView类似
//        layoutManager=new StaggeredGridLayoutManager(3, OrientationHelper.VERTICAL);    // 显示瀑布流效果 
        recyclerView= (RecyclerView) findViewById(R.id.recyclerview);
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setAdapter(adapter);
        MyDividerItemDecoration itemDecoration=new MyDividerItemDecoration(this,LinearLayoutManager.VERTICAL);  // 每一个RecyclerView的item之间的装饰（间隔，可设置自己想要的效果，如：间隔线、分组等）
        itemDecoration.setGroupListener(groupListener);
        recyclerView.addItemDecoration(itemDecoration);  //给recycler view添加item之间的间隔装饰
//        recyclerView.addItemDecoration(new MyGridRvDividerDecoration(this));
//        recyclerView.addItemDecoration(new MyStaggeredRvDividerDecotation(this));
}