public class SpacesItemDecoration extends RecyclerView.ItemDecoration {
private int mSpace;
private int mSpanCount;
// RecyclerView有多少列 private boolean mHasPadding;
// RecyclerView是否有Padding public SpacesItemDecoration(int mSpace) {
this.mSpace = mSpace;
this.mHasPadding = true;
}
public SpacesItemDecoration(int mSpace, boolean hasPadding) {
this.mSpace = mSpace;
this.mHasPadding = hasPadding;
}
@Override public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
// 初始化列数 if (mSpanCount == 0) {
this.mSpanCount = ((GridLayoutManager) parent.getLayoutManager()).getSpanCount();
}
int position = parent.getChildAdapterPosition(view);
// item position int column = position % mSpanCount;
// item column if (mHasPadding) {
outRect.left = mSpace - column * mSpace / mSpanCount;
// spacing - column * ((1f / spanCount) * spacing) outRect.right = (column + 1) * mSpace / mSpanCount;
// (column + 1) * ((1f / spanCount) * spacing) if (position < mSpanCount) {
// top edge outRect.top = mSpace;
}
outRect.bottom = mSpace;
// item bottom }
else {
outRect.left = column * mSpace / mSpanCount;
// column * ((1f / spanCount) * spacing) outRect.right = mSpace - (column + 1) * mSpace / mSpanCount;
// spacing - (column + 1) * ((1f / spanCount) * spacing) if (position >= mSpanCount) {
outRect.top = mSpace;
// item top }
}
}
public void setHasPadding(boolean hasPadding) {
this.mHasPadding = hasPadding;
}
}

public class MutiItemDecoration extends RecyclerView.ItemDecoration {
public enum Type {
VERTICAL, HORIZONTAL, ALL }
private Type type;
//分割线类型 private int dividerSize = 10;
//分割线尺寸 public MutiItemDecoration(MutiItemDecoration.Type type, int dividerSize) {
this.type = type;
this.dividerSize = dividerSize;
}
@Override public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
int spanCount = getSpanCount(parent);
int childCount = parent.getAdapter().getItemCount();
switch (type) {
case ALL: if (itemPosition % spanCount == 0) {
//第一列 if (isLastRaw(parent, itemPosition, spanCount, childCount)) {
outRect.set(0, 0, dividerSize / 2, 0);
}
else {
outRect.set(0, 0, dividerSize / 2, dividerSize);
}
}
else if (itemPosition % spanCount == spanCount - 1) {
//最后一列 if (isLastRaw(parent, itemPosition, spanCount, childCount)) {
outRect.set(dividerSize / 2, 0, 0, 0);
}
else {
outRect.set(dividerSize / 2, 0, 0, dividerSize);
}
}
else {
//中间列 if (isLastRaw(parent, itemPosition, spanCount, childCount)) {
outRect.set(dividerSize / 2, 0, dividerSize / 2, 0);
}
else {
outRect.set(dividerSize / 2, 0, dividerSize / 2, dividerSize);
}
}
break;
case VERTICAL: if (isLastRaw(parent, itemPosition, spanCount, childCount)) {
outRect.set(0, 0, 0, 0);
}
else {
outRect.set(0, 0, 0, dividerSize);
}
break;
case HORIZONTAL: if (isLastColum(parent, itemPosition, spanCount, childCount)) {
outRect.set(0, 0, 0, 0);
}
else {
outRect.set(0, 0, dividerSize, 0);
}
break;
}
}
// 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) return true;
}
else {
if (pos == childCount - 1) 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) return true;
}
else {
if (pos == childCount - 1) return true;
}
return false;
}
//返回列数 private int getSpanCount(RecyclerView parent) {
RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
if (layoutManager instanceof GridLayoutManager) {
return ((GridLayoutManager) layoutManager).getSpanCount();
}
return -1;
}
}

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 = ContextCompat.getDrawable(context, R.drawable.shape_divider);
a.recycle();
}
@Override public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
drawHorizontal(c, parent);
drawVertical(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) {
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();
if (i % 2 == 1) {
final int top = child.getTop() - params.topMargin;
final int bottom = child.getBottom() + params.bottomMargin;
final int left = child.getLeft() - params.rightMargin;
final int right = left + mDivider.getIntrinsicWidth() / 2;
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
else {
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() / 2;
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
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());
}
}
}