private View findCenterView(LinearLayoutManager lm) {
int minDistance = 0;
View view = null;
View returnView = null;
boolean notFound = true;
for (int i = lm.findFirstVisibleItemPosition();
i <= lm.findLastVisibleItemPosition() && notFound;
i++) {
view = lm.findViewByPosition(i);
int center =
lm.getOrientation() == LinearLayoutManager.HORIZONTAL
? (view.getLeft() + view.getRight()) / 2
: (view.getTop() + view.getBottom()) / 2;
int leastDifference = Math.abs(mCenterPivot - center);
if (leastDifference <= minDistance || i == lm.findFirstVisibleItemPosition()) {
minDistance = leastDifference;
returnView = view;
setCenterView(returnView);
} else {
notFound = false;
}
}
return returnView;
}
@Override
public void onActivityCreated(final Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
final View view = getView();
if (view == null) throw new AssertionError();
final Context viewContext = view.getContext();
mMultiSelectManager = getMultiSelectManager();
final MessageEntriesAdapter adapter = getAdapter();
final RecyclerView recyclerView = getRecyclerView();
final LinearLayoutManager layoutManager = getLayoutManager();
mNavigationHelper =
new RecyclerViewNavigationHelper(recyclerView, layoutManager, adapter, this);
adapter.setListener(this);
final DividerItemDecoration itemDecoration =
new DividerItemDecoration(viewContext, layoutManager.getOrientation());
final Resources res = viewContext.getResources();
final int decorPaddingLeft =
res.getDimensionPixelSize(R.dimen.element_spacing_normal) * 3
+ res.getDimensionPixelSize(R.dimen.icon_size_status_profile_image);
itemDecoration.setPadding(decorPaddingLeft, 0, 0, 0);
itemDecoration.setDecorationEndOffset(1);
recyclerView.addItemDecoration(itemDecoration);
getLoaderManager().initLoader(0, null, this);
showProgress();
}
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
LinearLayoutManager lm = (LinearLayoutManager) recyclerView.getLayoutManager();
if (mCenterPivot == 0) {
mCenterPivot =
lm.getOrientation() == LinearLayoutManager.HORIZONTAL
? (recyclerView.getLeft() + recyclerView.getRight())
: (recyclerView.getTop() + recyclerView.getBottom());
}
if (!mAutoSet) {
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
View view = findCenterView(lm);
int position = recyclerView.getChildPosition(view);
Log.i("CenterLockListener", "list-position" + position);
Toast.makeText(context, "list-position" + position, Toast.LENGTH_SHORT).show();
int viewCenter =
lm.getOrientation() == LinearLayoutManager.HORIZONTAL
? (view.getLeft() + view.getRight()) / 2
: (view.getTop() + view.getBottom()) / 2;
int scrollNeeded = viewCenter - mCenterPivot;
if (lm.getOrientation() == LinearLayoutManager.HORIZONTAL) {
recyclerView.smoothScrollBy(scrollNeeded, 0);
} else {
recyclerView.smoothScrollBy(0, (int) (scrollNeeded));
}
mAutoSet = true;
}
}
if (newState == RecyclerView.SCROLL_STATE_DRAGGING
|| newState == RecyclerView.SCROLL_STATE_SETTLING) {
mAutoSet = false;
}
}
private int getOrientation(RecyclerView parent) {
if (parent.getLayoutManager() instanceof LinearLayoutManager) {
LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
return layoutManager.getOrientation();
} else {
throw new IllegalStateException(
"ColorDividerItemDecoration can only be used with a LinearLayoutManager.");
}
}