@Override
public int clampViewPositionVertical(final View child, final int top, final int dy) {
final int current = mDrawer.getHeaderTop();
if (!Float.isNaN(mDx) && mDrawer.isValidScroll(mDx, dy)) {
mScrollingHeaderByHelper = false;
return current;
}
if (dy > 0 && mDrawer.canScrollCallback(-dy) && mDrawer.isTouchingScrollableContent()) {
if (!mDrawer.isUsingDragHelper()) {
// Scrolling up while list still has space to scroll, so make header still
mScrollingHeaderByHelper = false;
return current;
} else {
mDrawer.scrollByCallback(-dy);
mScrollingHeaderByHelper = false;
return current;
}
}
final int min = mDrawer.getHeaderTopMinimum(), max = mDrawer.getHeaderTopMaximum();
if (top < min && mDrawer.isTouchingScrollableContent() && mDrawer.isUsingDragHelper()) {
mDrawer.scrollByCallback(-dy);
}
mScrollingHeaderByHelper = true;
return MathUtils.clamp(top, min, max);
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
final int top = mDrawer.getHeaderTop(), min = mDrawer.getHeaderTopMinimum();
final boolean showingFullContent = top <= min, flingUp = velocityY < 0;
final boolean verticalFling = Math.abs(velocityY) > Math.abs(velocityX);
if (!verticalFling) return true;
if (showingFullContent) {
if (flingUp) {
// Fling list up when showing full content
if (mDrawer.isScrollingContentCallback()) {
mDrawer.flingCallback(-velocityY);
}
} else {
// Fling down when list reached top and not dragging user ViewDragHelper,
// so we fling header down here
if (!mDrawer.canScrollCallback(1) && !mDrawer.isUsingDragHelper()) {
mDrawer.flingHeader(velocityY);
}
}
} else {
// Header still visible
}
return true;
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
if (!mDrawer.isUsingDragHelper() && mDrawer.isValidScroll(distanceY, distanceX)) {
final int offset = mDrawer.getHeaderTop(), min = mDrawer.getHeaderTopMinimum();
if (!mDrawer.canScrollCallback(-1)) {
if (distanceY < 0) {
if (!mDrawer.isScrollingHeaderByHelper()) {
mDrawer.offsetHeaderBy(Math.round(-distanceY));
}
mDrawer.setScrollingHeaderByGesture(true);
} else if (distanceY > 0 && offset > min) {
// Scrolling up when scrolling to list top, so we cancel touch event and scrolling
// header up
mDrawer.cancelTouchCallback();
if (!mDrawer.isScrollingHeaderByHelper()) {
mDrawer.offsetHeaderBy(Math.round(-distanceY));
}
} else if (offset <= min) {
mDrawer.scrollByCallback(-distanceX);
}
}
}
return true;
}