支持上下拉刷新的RecycleView，基于androidPullToRefresh，添加RecycleView HeaderView

public class PullToRefreshRecycleView extends PullToRefreshBase<RecyclerView> {

private OnHeaderRefreshListener<RecyclerView> m_OnHeaderRefreshListener;
private OnFooterRefreshListener<RecyclerView> m_OnFooterRefreshListener;

private final OnRefreshListener2<RecyclerView> m_OnRefreshListener = new OnRefreshListener2<RecyclerView>() {

@Override
public void onPullDownToRefresh(PullToRefreshBase<RecyclerView> view) {
if (m_OnHeaderRefreshListener != null) {
m_OnHeaderRefreshListener.onHeaderRefresh(view);
}
}

@Override
public void onPullUpToRefresh(PullToRefreshBase<RecyclerView> view) {
if (m_OnFooterRefreshListener != null) {
m_OnFooterRefreshListener.onFooterRefresh(view);
}
}

};

@Override
protected void onRefreshing(boolean doScroll) {
super.onRefreshing(doScroll);
if(Mode.PULL_FROM_END == getCurrentMode()){
getFooterLayout().refreshing();
}else if(Mode.PULL_FROM_START == getCurrentMode()){
getHeaderLayout().refreshing();
}
}

@Override
protected void onReleaseToRefresh() {
super.onReleaseToRefresh();
inLoad = false;
}

private RecyclerView view;

public PullToRefreshRecycleView(Context context) {
super(context);
init();
}

public PullToRefreshRecycleView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}

public PullToRefreshRecycleView(Context context, Mode mode) {
super(context, mode);
init();
}

public PullToRefreshRecycleView(Context context, Mode mode, AnimationStyle style) {
super(context, mode, style);
init();
}

private void init(){
setOnRefreshListener(m_OnRefreshListener);
}

@Override
public Orientation getPullToRefreshScrollDirection() {
return Orientation.VERTICAL;
}

@Override
protected RecyclerView createRefreshableView(Context context, AttributeSet attrs) {
view = new RecyclerView(context, attrs);
view.setId(R.id.discovery_recycle_view);
return view;
}

@Override
protected boolean isReadyForPullEnd() {
View view = getRefreshableView().getChildAt(getRefreshableView().getChildCount() - 1);
if (null != view) {
return getRefreshableView().getBottom() >= view.getBottom() - 1;
}
return false;
}

@Override
protected boolean isReadyForPullStart() {
View view = getRefreshableView().getChildAt(0);

if (view != null) {
return view.getTop() >= getRefreshableView().getTop();
}
return false;
}

@Override
public void setOnHeaderRefreshListener(OnHeaderRefreshListener l) {
m_OnHeaderRefreshListener = l;
}

@Override
public void setOnFooterRefreshListener(OnFooterRefreshListener l) {
m_OnFooterRefreshListener = l;
}

@Override
public void onHeaderRefreshComplete() {
onRefreshComplete();
}

@Override
public void onFooterRefreshComplete() {
onRefreshComplete();
}

@Override
public void setDisableHeaderRefresh(boolean canNot) {
if (canNot) {
switch (getMode()) {
case BOTH:
setMode(Mode.PULL_FROM_END);
break;
case PULL_FROM_START:
setMode(Mode.DISABLED);
break;
}
} else {
switch (getMode()) {
case BOTH:
case PULL_FROM_END:
setMode(Mode.BOTH);
break;
default:
setMode(Mode.PULL_FROM_START);
break;
}
}
}

@Override
public void setDisableFootRefresh(boolean canNot) {
if (canNot) {
switch (getMode()) {
case BOTH:
setMode(Mode.PULL_FROM_START);
break;
case PULL_FROM_END:
setMode(Mode.DISABLED);
break;
}
} else {
switch (getMode()) {
case BOTH:
case PULL_FROM_START:
setMode(Mode.BOTH);
break;
default:
setMode(Mode.PULL_FROM_END);
break;
}
}
}

@Override
public void setLastUpdated(CharSequence lastUpdated) {
getLoadingLayoutProxy().setLast
4000
UpdatedLabel(lastUpdated);
}

public void setLayoutManager(RecyclerView.LayoutManager layout) {
if (null != view) {
view.setLayoutManager(layout);
}
}

public void setAdapter(RecyclerView.Adapter adapter) {
if (null != view) {
view.setAdapter(adapter);
}
}

public void addItemDecoration(RecyclerView.ItemDecoration decor) {
if (null != view) {
view.addItemDecoration(decor);
}
}

private int getFirstVisiblePosition() {
View firstVisibleChild = getRefreshableView().getChildAt(0);
return firstVisibleChild != null ? getRefreshableView()
.getChildAdapterPosition(firstVisibleChild) : -1;
}

private int getLastVisiblePosition() {
View lastVisibleChild = getRefreshableView().getChildAt(getRefreshableView()
.getChildCount() - 1);
return lastVisibleChild != null ? getRefreshableView()
.getChildAdapterPosition(lastVisibleChild) : -1;
}

public void moveToPosition(int n) {
int firstItem = getFirstVisiblePosition();
int lastItem = getLastVisiblePosition();
if (n <= firstItem) {
getRefreshableView().scrollToPosition(n);
} else if (n <= lastItem) {
int top = getRefreshableView().getChildAt(n - firstItem).getTop();
getRefreshableView().scrollBy(0, top);
} else {
getRefreshableView().scrollToPosition(n);
}
}
}

private PullToRefreshRecycleView discoveryRecycleView;
//设置瀑布流的LayoutManager，还可以实现GridView,ListView等
discoveryRecycleView.setLayoutManager(new StaggeredGridLayoutManager(NUM_COLUMNS,
StaggeredGridLayoutManager.VERTICAL));

//添加头部View
discoveryAdapter.addHeadView(R.layout.refresh_view_header);

discoveryRecycleView.setAdapter(discoveryAdapter);

//设置分割线样式
discoveryRecycleView.addItemDecoration(new DividerGridItemDecoration(getResources(), R.color.white,
R.dimen.discovery_item_divider_size, discoveryRecycleView.getOrientation()));

discoveryRecycleView.setDisableHeaderRefresh(false);
discoveryRecycleView.setDisableFootRefresh(false);

discoveryRecycleView.setOnHeaderRefreshListener(mHeaderRefreshListener);
discoveryRecycleView.setOnFooterRefreshListener(mOnFooterRefreshListener);

public class DiscoveryDetailRecycleViewStageredAdapter extends DiscoveryAdapter {
private final Logger log = Logger.getLogger(DiscoveryDetailRecycleViewStageredAdapter.class);
private static final int TYPE_HEADER = 0, TYPE_ITEM = 1, TYPE_FOOT = 2;

public DiscoveryDetailRecycleViewStageredAdapter(Context context, List<DiscoveryItemModel> discoveryList) {
super(context, discoveryList);
}

public void addHeadView(int view) {
headViewId = view;
headViewSize = 1;
isAddHead = true;
}

public int hasHeadView() {
return headViewSize;
}

public void addFootView(int view) {
footViewId = view;
footViewSize = 1;
isAddFoot = true;
}

@Override
public DiscoveryItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = null;
switch (viewType) {
case TYPE_HEADER:
view = LayoutInflater.from(parent.getContext()).inflate(headViewId, parent, false);
break;
case TYPE_ITEM:
return super.onCreateViewHolder(parent, viewType);
case TYPE_FOOT:
view = LayoutInflater.from(parent.getContext()).inflate(footViewId, parent, false);
break;
}
return new DiscoveryItemViewHolder(view);
}

@Override
public void onBindViewHolder(DiscoveryItemViewHolder holder, int position) {
switch (holder.getItemViewType()) {
case TYPE_HEADER:
//将头部View 变为横向铺满
StaggeredGridLayoutManager.LayoutParams clp = (StaggeredGridLayoutManager.LayoutParams) holder.cardView.getLayoutParams();
if (clp != null)
clp.setFullSpan(true);

holder.bindHeader(title, subTitle, coverUrl);
break;

case TYPE_ITEM:
super.onBindViewHolder(holder, position);
break;

case TYPE_FOOT:
StaggeredGridLayoutManager.LayoutParams clp1 = (StaggeredGridLayoutManager.LayoutParams) holder.cardView.getLayoutParams();
clp1.setFullSpan(true);
break;
}
}

@Override
public int getItemViewType(int position) {

int type = TYPE_ITEM;
if (headViewSize == 1 && position == 0) {
type = TYPE_HEADER;
} else if (footViewSize == 1 && position == getItemCount() - 1) {
//最后一个位置
type = TYPE_FOOT;
}
return type;
}

@Override
public int getItemCount() {
return discoveryList.size() + headViewSize + footViewSize;
}

@Override
public Object getItem(int position) {
position-=headViewSize;
return super.getItem(position);
}
}

public class DividerGridItemDecoration extends RecyclerView.ItemDecoration {
private Drawable mDivider;
private int mSize;
private int mOrientation;

public DividerGridItemDecoration(Resources resources, @ColorRes int color,
@DimenRes int size, int orientation) {
mDivider = new ColorDrawable(resources.getColor(color));
mSize = resources.getDimensionPixelSize(size);
mOrientation = orientation;
}

@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
int left;
int right;
int top;
int bottom;
if (mOrientation == LinearLayoutManager.HORIZONTAL) {
top = parent.getPaddingTop();
bottom = parent.getHeight() - parent.getPaddingBottom();
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount - 1; i++) {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params =
(RecyclerView.LayoutParams) child.getLayoutParams();
left = child.getRight() + params.rightMargin;
right = left + mSize;
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
} else {
left = parent.getPaddingLeft();
right = parent.getWidth() - parent.getPaddingRight();
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount - 1; i++) {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params =
(RecyclerView.LayoutParams) child.getLayoutParams();
top = child.getBottom() + params.bottomMargin;
bottom = top + mSize;
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
}

@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
if (mOrientation == LinearLayoutManager.HORIZONTAL) {
outRect.set(0, 0, 0, mSize);
} else {
outRect.set(0, 0, mSize, 0);
}
}
}

private int getScollYDistance() {
LinearLayoutManager layoutManager = (LinearLayoutManager) showKeyFrameRv.getLayoutManager();
int position = layoutManager.findFirstVisibleItemPosition();
View firstVisiableChildView = layoutManager.findViewByPosition(position);
int itemWidth = firstVisiableChildView.getWidth();
return (position) * itemWidth - firstVisiableChildView.getLeft();
}