/**
* Returns view for specified item
*
* @param index the item index
* @return item view or empty view if index is out of bounds
*/
private View getItemView(int index) {
if (viewAdapter == null || viewAdapter.getItemsCount() == 0) {
return null;
}
int count = viewAdapter.getItemsCount();
if (!isValidItemIndex(index)) {
return viewAdapter.getEmptyItem(recycle.getEmptyItem(), itemsLayout);
} else {
while (index < 0) {
index = count + index;
}
}
index %= count;
return viewAdapter.getItem(index, recycle.getItem(), itemsLayout);
}
/**
* Scrolls the wheel
*
* @param delta the scrolling value
*/
private void doScroll(int delta) {
scrollingOffset += delta;
int itemHeight = getItemHeight();
int count = scrollingOffset / itemHeight;
int pos = currentItem - count;
int itemCount = viewAdapter.getItemsCount();
int fixPos = scrollingOffset % itemHeight;
if (Math.abs(fixPos) <= itemHeight / 2) {
fixPos = 0;
}
if (isCyclic && itemCount > 0) {
if (fixPos > 0) {
pos--;
count++;
} else if (fixPos < 0) {
pos++;
count--;
}
// fix position by rotating
while (pos < 0) {
pos += itemCount;
}
pos %= itemCount;
} else {
//
if (pos < 0) {
count = currentItem;
pos = 0;
} else if (pos >= itemCount) {
count = currentItem - itemCount + 1;
pos = itemCount - 1;
} else if (pos > 0 && fixPos > 0) {
pos--;
count++;
} else if (pos < itemCount - 1 && fixPos < 0) {
pos++;
count--;
}
}
int offset = scrollingOffset;
if (pos != currentItem) {
setCurrentItem(pos, false);
} else {
invalidate();
}
// update offset
scrollingOffset = offset - count * itemHeight;
if (scrollingOffset > getHeight()) {
scrollingOffset = scrollingOffset % getHeight() + getHeight();
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (viewAdapter != null && viewAdapter.getItemsCount() > 0) {
updateView();
drawItems(canvas);
drawCenterRect(canvas);
}
if (drawShadows) drawShadows(canvas);
}
/**
* Sets the current item. Does nothing when index is wrong.
*
* @param index the item index
* @param animated the animation flag
*/
public void setCurrentItem(int index, boolean animated) {
if (viewAdapter == null || viewAdapter.getItemsCount() == 0) {
return; // throw?
}
int itemCount = viewAdapter.getItemsCount();
if (index < 0 || index >= itemCount) {
if (isCyclic) {
while (index < 0) {
index += itemCount;
}
index %= itemCount;
} else {
return; // throw?
}
}
if (index != currentItem) {
if (animated) {
int itemsToScroll = index - currentItem;
if (isCyclic) {
int scroll = itemCount + Math.min(index, currentItem) - Math.max(index, currentItem);
if (scroll < Math.abs(itemsToScroll)) {
itemsToScroll = itemsToScroll < 0 ? scroll : -scroll;
}
}
scroll(itemsToScroll, 0);
} else {
scrollingOffset = 0;
int old = currentItem;
currentItem = index;
notifyChangingListeners(old, currentItem);
invalidate();
}
}
}
/**
* Checks whether intem index is valid
*
* @param index the item index
* @return true if item index is not out of bounds or the wheel is cyclic
*/
private boolean isValidItemIndex(int index) {
return viewAdapter != null
&& viewAdapter.getItemsCount() > 0
&& (isCyclic || index >= 0 && index < viewAdapter.getItemsCount());
}