This library is not good for GridLayoutManager. Some Suggesttion.
liaolintao opened this issue · 0 comments
liaolintao commented
Problem
Method(com.yqritc.recyclerviewflexibledivider.FlexibleDividerDecoration#getGroupIndex )
calls frequently, and that method consume too much time, ui thread do too much.
google source code :
GridLayoutManager.SpanSizeLookup#getSpanGroupIndex(int, int) .
https://developer.android.com/reference/android/support/v7/widget/GridLayoutManager.SpanSizeLookup.html?hl=ja#getSpanGroupIndex(int;
public int getSpanGroupIndex(int adapterPosition, int spanCount) {
int span = 0;
int group = 0;
int positionSpanSize = getSpanSize(adapterPosition);
for (int i = 0; i < adapterPosition; i++) {
int size = getSpanSize(i);
span += size;
if (span == spanCount) {
span = 0;
group++;
} else if (span > spanCount) {
// did not fit, moving to next row / column
span = size;
group++;
}
}
if (span + positionSpanSize > spanCount) {
group++;
}
return group;
}
My Suggesttion
Please dont't frequently use method GridLayoutManager.SpanSizeLookup#getSpanGroupIndex(int, int) .
I do it ,and ui thread is good for show.
My Simple Code for GridLayoutManager
import android.graphics.Canvas;
import android.graphics.Rect;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.OrientationHelper;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.RecyclerView.ItemDecoration;
import android.support.v7.widget.RecyclerView.State;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.View;
public class ListSpacingDecoration extends ItemDecoration {
private static final String TAG = ListSpacingDecoration.class.getSimpleName();
private static final int VERTICAL = OrientationHelper.VERTICAL;
private int orientation = -1;
private int spanCount = -1;
private int spacing;
private int halfSpacing;
public ListSpacingDecoration(int spacing) {
super();
this.spacing = spacing;
this.halfSpacing = spacing / 2;
}
/**
* 可以通过outRect.set()为每个Item设置一定的偏移量,主要用于绘制Decorator
*/
@Override
public void getItemOffsets(Rect outRect, final View view, RecyclerView parent, State state) {
// super.getItemOffsets(outRect, view, parent, state);
if (orientation == -1) {
orientation = getOrientation(parent);
}
if (spanCount == -1) {
spanCount = getTotalSpan(parent);
}
int childCount = parent.getLayoutManager().getItemCount();
int childIndex = parent.getChildAdapterPosition(view);
int itemSpanSize = getItemSpanSize(parent, childIndex);
int spanIndex = getItemSpanIndex(parent, childIndex);
// LogUtils.d(TAG, "getItemOffsets childCount = " + childCount + " - childIndex = " + childIndex + " : itemSpanSize = "
// + itemSpanSize + " : spanIndex = " + spanIndex);
/* INVALID SPAN */
if (spanCount < 1)
return;
setSpacings(outRect, parent, childCount, childIndex, itemSpanSize, spanIndex);
}
/**
* onDraw方法先于drawChildren
*/
@Override
public void onDraw(Canvas c, RecyclerView parent, State state) {
// TODO
super.onDraw(c, parent, state);
}
/**
* onDrawOver在drawChildren之后,一般我们选择复写其中一个即可
*/
@Override
public void onDrawOver(Canvas c, RecyclerView parent, State state) {
// TODO
super.onDrawOver(c, parent, state);
}
protected void setSpacings(Rect outRect, RecyclerView parent, int childCount, int childIndex, int itemSpanSize,
int spanIndex) {
outRect.top = halfSpacing;
outRect.bottom = halfSpacing;
outRect.left = halfSpacing;
outRect.right = halfSpacing;
if (isTopEdge(parent, childCount, childIndex, itemSpanSize, spanIndex)) {
outRect.top = spacing;
}
if (isLeftEdge(parent, childCount, childIndex, itemSpanSize, spanIndex)) {
// outRect.left = spacing;
outRect.left = 0;
}
if (isRightEdge(parent, childCount, childIndex, itemSpanSize, spanIndex)) {
// outRect.right = spacing;
outRect.right = 0;
}
if (isBottomEdge(parent, childCount, childIndex, itemSpanSize, spanIndex)) {
outRect.bottom = spacing;
}
}
@SuppressWarnings("all")
protected int getTotalSpan(RecyclerView parent) {
RecyclerView.LayoutManager mgr = parent.getLayoutManager();
if (mgr instanceof GridLayoutManager) {
return ((GridLayoutManager) mgr).getSpanCount();
} else if (mgr instanceof StaggeredGridLayoutManager) {
return ((StaggeredGridLayoutManager) mgr).getSpanCount();
} else if (mgr instanceof LinearLayoutManager) {
return 1;
}
return -1;
}
@SuppressWarnings("all")
protected int getItemSpanSize(RecyclerView parent, int childIndex) {
RecyclerView.LayoutManager mgr = parent.getLayoutManager();
if (mgr instanceof GridLayoutManager) {
return ((GridLayoutManager) mgr).getSpanSizeLookup().getSpanSize(childIndex);
} else if (mgr instanceof StaggeredGridLayoutManager) {
return 1;
} else if (mgr instanceof LinearLayoutManager) {
return 1;
}
return -1;
}
@SuppressWarnings("all")
protected int getItemSpanIndex(RecyclerView parent, int childIndex) {
RecyclerView.LayoutManager mgr = parent.getLayoutManager();
if (mgr instanceof GridLayoutManager) {
return ((GridLayoutManager) mgr).getSpanSizeLookup().getSpanIndex(childIndex, spanCount);
} else if (mgr instanceof StaggeredGridLayoutManager) {
return childIndex % spanCount;
} else if (mgr instanceof LinearLayoutManager) {
return 0;
}
return -1;
}
@SuppressWarnings("all")
protected int getOrientation(RecyclerView parent) {
RecyclerView.LayoutManager mgr = parent.getLayoutManager();
if (mgr instanceof LinearLayoutManager) {
return ((LinearLayoutManager) mgr).getOrientation();
} else if (mgr instanceof GridLayoutManager) {
return ((GridLayoutManager) mgr).getOrientation();
} else if (mgr instanceof StaggeredGridLayoutManager) {
return ((StaggeredGridLayoutManager) mgr).getOrientation();
}
return VERTICAL;
}
protected boolean isLeftEdge(RecyclerView parent, int childCount, int childIndex, int itemSpanSize, int spanIndex) {
if (orientation == VERTICAL) {
return spanIndex == 0;
} else {
return (childIndex == 0) || isFirstItemEdgeValid((childIndex < spanCount), parent, childIndex);
}
}
protected boolean isRightEdge(RecyclerView parent, int childCount, int childIndex, int itemSpanSize, int spanIndex) {
if (orientation == VERTICAL) {
return (spanIndex + itemSpanSize) == spanCount;
} else {
return isLastItemEdgeValid((childIndex >= childCount - spanCount), parent, childCount, childIndex, spanIndex);
}
}
protected boolean isTopEdge(RecyclerView parent, int childCount, int childIndex, int itemSpanSize, int spanIndex) {
if (orientation == VERTICAL) {
return (childIndex == 0) || isFirstItemEdgeValid((childIndex < spanCount), parent, childIndex);
} else {
return spanIndex == 0;
}
}
protected boolean isBottomEdge(RecyclerView parent, int childCount, int childIndex, int itemSpanSize, int spanIndex) {
if (orientation == VERTICAL) {
return isLastItemEdgeValid((childIndex >= childCount - spanCount), parent, childCount, childIndex, spanIndex);
} else {
return (spanIndex + itemSpanSize) == spanCount;
}
}
protected boolean isFirstItemEdgeValid(boolean isOneOfFirstItems, RecyclerView parent, int childIndex) {
int totalSpanArea = 0;
if (isOneOfFirstItems) {
for (int i = childIndex; i >= 0; i--) {
totalSpanArea = totalSpanArea + getItemSpanSize(parent, i);
}
}
return isOneOfFirstItems && totalSpanArea <= spanCount;
}
protected boolean isLastItemEdgeValid(boolean isOneOfLastItems, RecyclerView parent, int childCount, int childIndex,
int spanIndex) {
int totalSpanRemaining = 0;
if (isOneOfLastItems) {
for (int i = childIndex; i < childCount; i++) {
totalSpanRemaining = totalSpanRemaining + getItemSpanSize(parent, i);
}
}
return isOneOfLastItems && (totalSpanRemaining <= spanCount - spanIndex);
}
}