//public void Logi(string msg)
//{
// Log.Info(TAG, msg);
//}
//public void Loge(string err)
//{
// Log.Error(TAG, err);
//}
//--- 处理布局 ----------------------------------------------------------------------------------
/**
* 布局子View
*
* @param recycler Recycler
* @param state State
*/
public override void OnLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state)
{
Log.Info(TAG, "Item onLayoutChildren");
Log.Info(TAG, "Item onLayoutChildren isPreLayout = " + state.IsPreLayout);
Log.Info(TAG, "Item onLayoutChildren isMeasuring = " + state.IsMeasuring);
Log.Info(TAG, "Item onLayoutChildren state = " + state);
// 如果是 preLayout 则不重新布局
if (state.IsPreLayout || !state.DidStructureChange())
{
return;
}
if (ItemCount == 0)
{
RemoveAndRecycleAllViews(recycler);
// 页面变化回调
SetPageCount(0);
SetPageIndex(0, false);
return;
}
else
{
SetPageCount(GetTotalPageCount());
SetPageIndex(GetPageIndexByOffset(), false);
}
// 计算页面数量
int mPageCount = ItemCount / mOnePageSize;
if (ItemCount % mOnePageSize != 0)
{
mPageCount++;
}
// 计算可以滚动的最大数值，并对滚动距离进行修正
if (CanScrollHorizontally())
{
mMaxScrollX = (mPageCount - 1) * GetUsableWidth();
mMaxScrollY = 0;
if (mOffsetX > mMaxScrollX)
{
mOffsetX = mMaxScrollX;
}
}
else
{
mMaxScrollX = 0;
mMaxScrollY = (mPageCount - 1) * GetUsableHeight();
if (mOffsetY > mMaxScrollY)
{
mOffsetY = mMaxScrollY;
}
}
// 接口回调
// setPageCount(mPageCount);
// setPageIndex(mCurrentPageIndex, false);
Logi("count = " + ItemCount);
if (mItemWidth <= 0)
{
mItemWidth = GetUsableWidth() / mColumns;
}
if (mItemHeight <= 0)
{
mItemHeight = GetUsableHeight() / mRows;
}
mWidthUsed = GetUsableWidth() - mItemWidth;
mHeightUsed = GetUsableHeight() - mItemHeight;
// 预存储两页的View显示区域
for (int i = 0; i < mOnePageSize * 2; i++)
{
GetItemFrameByPosition(i);
}
if (mOffsetX == 0 && mOffsetY == 0)
{
// 预存储View
for (int i = 0; i < mOnePageSize; i++)
{
if (i >= ItemCount)
{
break; // 防止数据过少时导致数组越界异常
}
View view = recycler.GetViewForPosition(i);
AddView(view);
MeasureChildWithMargins(view, mWidthUsed, mHeightUsed);
}
}
// 回收和填充布局
RecycleAndFillItems(recycler, state, true);
}
