private void updateHeaderVisibilities() {
int top = clippingToPadding ? getPaddingTop() : 0;
int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
View child = getChildAt(i);
if (adapter.isHeader(child)) {
if (child.getTop() < top) {
if (child.getVisibility() != View.INVISIBLE) {
child.setVisibility(View.INVISIBLE);
}
} else {
if (child.getVisibility() != View.VISIBLE) {
child.setVisibility(View.VISIBLE);
}
}
}
}
}
private void scrollChanged(int firstVisibleItem) {
if (adapter == null || frame == null) {
return;
}
int adapterCount = adapter.getCount();
if (adapterCount == 0 || !areHeadersSticky) {
frame.removeHeader();
return;
}
final int listViewHeaderCount = getHeaderViewsCount();
firstVisibleItem = getFixedFirstVisibleItem(firstVisibleItem) - listViewHeaderCount;
if (firstVisibleItem < 0 || firstVisibleItem > adapterCount - 1) {
if (currentHeaderId != null || dataChanged) {
currentHeaderId = null;
frame.removeHeader();
updateHeaderVisibilities();
invalidate();
dataChanged = false;
}
return;
}
boolean headerHasChanged = false;
long newHeaderId = adapter.getHeaderId(firstVisibleItem);
if (currentHeaderId == null || currentHeaderId != newHeaderId) {
headerPosition = firstVisibleItem;
View header = adapter.getHeaderView(headerPosition, frame.removeHeader(), frame);
header.setOnClickListener(this);
frame.setHeader(header);
headerHasChanged = true;
}
currentHeaderId = newHeaderId;
int childCount = getChildCount();
if (childCount > 0) {
View viewToWatch = null;
int watchingChildDistance = Integer.MAX_VALUE;
boolean viewToWatchIsFooter = false;
for (int i = 0; i < childCount; i++) {
View child = getChildAt(i);
boolean childIsFooter = footerViews != null && footerViews.contains(child);
int childDistance;
if (clippingToPadding) {
childDistance = child.getTop() - getPaddingTop();
} else {
childDistance = child.getTop();
}
if (childDistance < 0) {
continue;
}
if (viewToWatch == null
|| (!viewToWatchIsFooter && !adapter.isHeader(viewToWatch))
|| ((childIsFooter || adapter.isHeader(child))
&& childDistance < watchingChildDistance)) {
viewToWatch = child;
viewToWatchIsFooter = childIsFooter;
watchingChildDistance = childDistance;
}
}
int headerHeight = frame.getHeaderHeight();
int headerBottomPosition = 0;
if (viewToWatch != null && (viewToWatchIsFooter || adapter.isHeader(viewToWatch))) {
if (firstVisibleItem == listViewHeaderCount
&& getChildAt(0).getTop() > 0
&& !clippingToPadding) {
headerBottomPosition = 0;
} else {
if (clippingToPadding) {
headerBottomPosition = Math.min(viewToWatch.getTop(), headerHeight + getPaddingTop());
headerBottomPosition =
headerBottomPosition < getPaddingTop()
? headerHeight + getPaddingTop()
: headerBottomPosition;
} else {
headerBottomPosition = Math.min(viewToWatch.getTop(), headerHeight);
headerBottomPosition = headerBottomPosition < 0 ? headerHeight : headerBottomPosition;
}
}
} else {
headerBottomPosition = headerHeight;
if (clippingToPadding) {
headerBottomPosition += getPaddingTop();
}
}
if (frame.getHeaderBottomPosition() != headerBottomPosition || headerHasChanged) {
frame.setHeaderBottomPosition(headerBottomPosition);
}
updateHeaderVisibilities();
}
}
