package com.github.jdsjlzx.ItemDecoration;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.support.annotation.ColorInt;
import android.support.annotation.ColorRes;
import android.support.annotation.DimenRes;
import android.support.v4.content.ContextCompat;
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.util.TypedValue;
import android.view.View;
import com.github.jdsjlzx.recyclerview.LRecyclerView;
import com.github.jdsjlzx.recyclerview.LRecyclerViewAdapter;
public class GridItemDecoration extends RecyclerView.ItemDecoration {
private int verticalSpace;
private int horizontalSpace;
private Paint mPaint;
public GridItemDecoration(int horizontalSpace, int verticalSpace, int colour) {
this.horizontalSpace = horizontalSpace;
this.verticalSpace = verticalSpace;
mPaint = new Paint();
mPaint.setColor(colour);
}
@Override
public void onDrawOver(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();
LRecyclerView recyclerView = (LRecyclerView) parent;
LRecyclerViewAdapter adapter = (LRecyclerViewAdapter) parent.getAdapter();
for (int i = 0; i < childCount; i++) {
if ((recyclerView.isOnTop() && (adapter.isHeader(i) || adapter.isRefreshHeader(i))) || adapter.isFooter(i)) {
c.drawRect(0, 0, 0, 0, mPaint);
} else {
final View child = parent.getChildAt(i);
final int top = child.getBottom();
final int bottom = top + verticalSpace;
int left = child.getLeft();
int right = child.getRight();
c.drawRect(left, top, right, bottom, mPaint);
}
}
}
public void drawVertical(Canvas c, RecyclerView parent) {
final int childCount = parent.getChildCount();
LRecyclerView recyclerView = (LRecyclerView) parent;
LRecyclerViewAdapter adapter = (LRecyclerViewAdapter) parent.getAdapter();
for (int i = 0; i < childCount; i++) {
if ((recyclerView.isOnTop() && (adapter.isHeader(i) || adapter.isRefreshHeader(i))) || adapter.isFooter(i)) {
c.drawRect(0, 0, 0, 0, mPaint);
} else {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
final int top = child.getTop();
final int bottom = child.getBottom() + verticalSpace;
final int left = child.getRight() + params.rightMargin;
final int right = left + horizontalSpace;
c.drawRect(left, top, right, bottom, mPaint);
}
}
}
/**
* @param parent RecyclerView
* @param pos 当前item的位置
* @param spanCount 每行显示的item个数
* @param childCount child个数
*/
private boolean isLastRaw(RecyclerView parent, int pos, int spanCount, int childCount) {
LayoutManager layoutManager = parent.getLayoutManager();
LRecyclerViewAdapter adapter = (LRecyclerViewAdapter) parent.getAdapter();
if (layoutManager instanceof GridLayoutManager) {
int leftCount = childCount - childCount % spanCount;//3
//leftCount:若childCount能被span整除为childCount否则为去掉最后一行的item总数
if ((pos - adapter.getHeaderViews().size() + 1) > leftCount) {
return true;
}
}
return false;
}
private boolean isLastColumn(RecyclerView parent, int pos, int spanCount) {
LayoutManager layoutManager = parent.getLayoutManager();
LRecyclerViewAdapter adapter = (LRecyclerViewAdapter) parent.getAdapter();
if (layoutManager instanceof GridLayoutManager) {
if ((pos - adapter.getHeaderViews().size()) % spanCount == 0)
// 如果是最后一列，则不需要绘制右边
return true;
}
return false;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, State state) {
super.getItemOffsets(outRect, view, parent, state);
int itemPosition = parent.getChildAdapterPosition(view);
int spanCount = getSpanCount(parent);
int childCount = parent.getAdapter().getItemCount();
LRecyclerViewAdapter adapter = (LRecyclerViewAdapter) parent.getAdapter();
if (adapter.isFooter(itemPosition) || adapter.isHeader(itemPosition) || adapter.isRefreshHeader(itemPosition)) {
//header，footer不进行绘制
outRect.set(0, 0, 0, 0);
} else {
if (!(parent.getLayoutManager() instanceof GridLayoutManager)) {
//LinearLayoutManager
if (itemPosition == (childCount - 2 - adapter.getHeaderViews().size()))
outRect.set(0, 0, 0, 0);
else
outRect.set(0, 0, 0, verticalSpace);
} else {
//GridLayoutManager
if (isLastRaw(parent, itemPosition, spanCount, childCount - 2 - adapter.getHeaderViews().size())) {
//最后一行
if (isLastColumn(parent, itemPosition, spanCount)) {
// 最后一行最后一列
outRect.set(0, 0, 0, verticalSpace);
} else {
// 最后一行不是最后一列
outRect.set(0, 0, horizontalSpace, verticalSpace);
}
} else {
//最后一列
if (isLastColumn(parent, itemPosition, spanCount)) {
// 最后一列最后一行
outRect.set(0, 0, 0, verticalSpace);
} else {
// 最后一列非最后一行
outRect.set(0, 0, horizontalSpace, verticalSpace);
}
}
}
}
}
public static class Builder {
private Context mContext;
private Resources mResources;
private int mHorizontal;
private int mVertical;
private int mColour;
public Builder(Context context) {
mContext = context;
mResources = context.getResources();
mHorizontal = 0;
mVertical = 0;
mColour = Color.BLACK;
}
/**
* Sets the divider colour
*
* @param resource the colour resource id
* @return the current instance of the Builder
*/
public Builder setColorResource(@ColorRes int resource) {
setColor(ContextCompat.getColor(mContext, resource));
return this;
}
/**
* Sets the divider colour
*
* @param color the colour
* @return the current instance of the Builder
*/
public Builder setColor(@ColorInt int color) {
mColour = color;
return this;
}
//通过dp设置垂直间距
public Builder setVertical(@DimenRes int vertical) {
this.mVertical = mResources.getDimensionPixelSize(vertical);
return this;
}
//通过px设置垂直间距
public Builder setVertical(float mVertical) {
this.mVertical = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, mVertical, mResources.getDisplayMetrics());
return this;
}
//通过dp设置水平间距
public Builder setHorizontal(@DimenRes int horizontal) {
this.mHorizontal = mResources.getDimensionPixelSize(horizontal);
return this;
}
//通过px设置水平间距
public Builder setHorizontal(float horizontal) {
this.mHorizontal = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PX, horizontal, mResources.getDisplayMetrics());
return this;
}
/**
* Instantiates a DividerDecoration with the specified parameters.
*
* @return a properly initialized DividerDecoration instance
*/
public GridItemDecoration build() {
return new GridItemDecoration(mHorizontal, mVertical, mColour);
}
}
}