万能的recyclerview分割线（线性，表格，瀑布流）

DividerItemDecoration ：

package com.zaxxkj.utils.rv;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
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 com.zaxxkj.utils.LogUtil;
import com.zaxxkj.utils.base.BaseDrawable;

public class DividerItemDecoration extends RecyclerView.ItemDecoration {


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

    private Drawable mDivider;

    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;

    private int mOrientation;

    /**
     * @param context
     * @param width   分割线宽
     * @param height  分割线高
     * @param color   分割线颜色 十进制
     */
    public DividerItemDecoration(Context context, int width, int height, int color) {
//        final TypedArray a = context.obtainStyledAttributes(ATTRS);
//        mDivider = a.getDrawable(0);
//        a.recycle();
        mDivider = new BaseDrawable(createRGBImage(Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_4444), color));
    }

    /**
     * LinearLayoutManager时的构造方法
     * @param context
     * @param orientation
     * @param width
     * @param height
     * @param color
     */
    public DividerItemDecoration(Context context, int orientation, int width, int height, int color) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
//        mDivider = new BaseDrawable(createRGBImage(Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_4444), color));
        setOrientation(orientation);
    }

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

    public static final Bitmap createRGBImage(Bitmap bitmap, int color) {
        int bitmap_w = bitmap.getWidth();
        int bitmap_h = bitmap.getHeight();
        int[] arrayColor = new int[bitmap_w * bitmap_h];
        int count = 0;
        for (int i = 0; i < bitmap_h; i++) {
            for (int j = 0; j < bitmap_w; j++) {
                int color1 = bitmap.getPixel(j, i);
                //这里也可以取出 R G B 可以扩展一下 做更多的处理，
                //暂时我只是要处理除了透明的颜色，改变其他的颜色
                if (color1 != 0) {
                } else {
                    color1 = color;
                }
                arrayColor[count] = color;
                count++;
            }
        }
        bitmap = Bitmap.createBitmap(arrayColor, bitmap_w, bitmap_h, Bitmap.Config.ARGB_4444);
        return bitmap;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {//这个时候垂直和水平方向都需要重新绘制
        RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof LinearLayoutManager) {
            LogUtil.e("linear------ondraw");
            if (mOrientation == VERTICAL_LIST) {
                drawVertical(c, parent);
            } else {
                drawHorizontal(c, parent);
            }
        } else {
            LogUtil.e("linear------ondraw");
            drawVertical(c, parent);
            drawHorizontal(c, parent);
        }

    }

    private int getSpanCount(RecyclerView parent) {
        // 列数
        int spanCount = -1;
        RecyclerView.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) {
        RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof LinearLayoutManager) {
            LogUtil.e("linear------drawHorizontal");
            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);
            }
        } else {
            LogUtil.e("linear------drawHorizontal");
            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) {
        RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof LinearLayoutManager) {
            LogUtil.e("linear------drawVertical");
            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);
            }
        } else {
            LogUtil.e("linear------drawVertical");
            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);
            }
        }
    }

    /**
     * 判断是否是最后一列
     */
    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;
    }

    /**
     * 是否是最后一行
     */
    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) {
        RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager||layoutManager instanceof StaggeredGridLayoutManager) {
            LogUtil.e("linear------getItemOffsets");
            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());
            }
        } else if (layoutManager instanceof LinearLayoutManager){

            LogUtil.e("linear------getItemOffsetsl");
            if (mOrientation == VERTICAL_LIST) {
                outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
            } else {
                outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
            }
        }

    }
}

BaseDrawable:

package com.zaxxkj.utils.base;

import android.graphics.Bitmap;
import android.graphics.BitmapShader;
import android.graphics.Canvas;
import android.graphics.ColorFilter;
import android.graphics.Paint;
import android.graphics.PixelFormat;
import android.graphics.RectF;
import android.graphics.Shader;
import android.graphics.drawable.Drawable;


public class BaseDrawable extends Drawable {
    private Paint mPaint;
    private Bitmap mBitmap;

    private RectF rectF;

    public BaseDrawable(Bitmap bitmap) {
        mBitmap = bitmap;
        BitmapShader bitmapShader = new BitmapShader(bitmap, Shader.TileMode.CLAMP,
                Shader.TileMode.CLAMP);
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setShader(bitmapShader);
    }

    @Override
    public void setBounds(int left, int top, int right, int bottom) {
        super.setBounds(left, top, right, bottom);
        rectF = new RectF(left, top, right, bottom);
    }

    @Override
    public void draw(Canvas canvas) {
        canvas.drawRect(rectF, mPaint);
//            canvas.drawRoundRect(rectF, 30, 30, mPaint);
    }

    @Override
    public int getIntrinsicWidth() {
        return mBitmap.getWidth();
    }

    @Override
    public int getIntrinsicHeight() {
        return mBitmap.getHeight();
    }

    @Override
    public void setAlpha(int alpha) {
        mPaint.setAlpha(alpha);
    }

    @Override
    public void setColorFilter(ColorFilter cf) {
        mPaint.setColorFilter(cf);
    }

    @Override
    public int getOpacity() {
        return PixelFormat.TRANSLUCENT;
    }

}