/**
* * This method determines which menu items get to be 'action items' that will appear in an
* action bar and which items should be 'overflow items' in a secondary menu. The rules are as
* follows:
*
* <p>Items are considered for inclusion in the order specified within the menu. There is a limit
* of mMaxActionItems as a total count, optionally including the overflow menu button itself. This
* is a soft limit; if an item shares a group ID with an item previously included as an action
* item, the new item will stay with its group and become an action item itself even if it breaks
* the max item count limit. This is done to limit the conceptual complexity of the items
* presented within an action bar. Only a few unrelated concepts should be presented to the user
* in this space, and groups are treated as a single concept.
*
* <p>There is also a hard limit of consumed measurable space: mActionWidthLimit. This limit may
* be broken by a single item that exceeds the remaining space, but no further items may be added.
* If an item that is part of a group cannot fit within the remaining measured width, the entire
* group will be demoted to overflow. This is done to ensure room for navigation and other
* affordances in the action bar as well as reduce general UI clutter.
*
* <p>The space freed by demoting a full group cannot be consumed by future menu items. Once items
* begin to overflow, all future items become overflow items as well. This is to avoid inadvertent
* reordering that may break the app's intended design.
*/
public void flagActionItems() {
if (!mIsActionItemsStale) {
return;
}
// Presenters flag action items as needed.
boolean flagged = false;
for (WeakReference<MenuPresenter> ref : mPresenters) {
final MenuPresenter presenter = ref.get();
if (presenter == null) {
mPresenters.remove(ref);
} else {
flagged |= presenter.flagActionItems();
}
}
if (flagged) {
mActionItems.clear();
mNonActionItems.clear();
ArrayList<MenuItemImpl> visibleItems = getVisibleItems();
final int itemsSize = visibleItems.size();
for (int i = 0; i < itemsSize; i++) {
MenuItemImpl item = visibleItems.get(i);
if (item.isActionButton()) {
mActionItems.add(item);
} else {
mNonActionItems.add(item);
}
}
} else {
// Nobody flagged anything, everything is a non-action item.
// (This happens during a first pass with no action-item presenters.)
mActionItems.clear();
mNonActionItems.clear();
mNonActionItems.addAll(getVisibleItems());
}
mIsActionItemsStale = false;
}
