@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;
}
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
super.onDraw(c, parent, state);
// layout basically just gets drawn on the reserved space on top of the first view
mLayout.layout(parent.getLeft(), 0, parent.getRight(), mLayout.getMeasuredHeight());
for (int i = 0; i < parent.getChildCount(); i++) {
View view = parent.getChildAt(i);
if (parent.getChildAdapterPosition(view) == 0) {
c.save();
final int height = mLayout.getMeasuredHeight();
final int top = view.getTop() - height;
c.translate(0, top);
mLayout.draw(c);
c.restore();
break;
}
}
}
public static View getFirstIntersectsChild(RecyclerView recyclerView) {
int childCount = recyclerView.getChildCount();
if (childCount > 0) {
for (int i = 0; i < childCount; i++) {
View child = recyclerView.getChildAt(i);
Rect rect1 =
new Rect(
recyclerView.getLeft(),
recyclerView.getTop(),
recyclerView.getRight(),
recyclerView.getBottom());
Rect rect2 = new Rect(child.getLeft(), child.getTop(), child.getRight(), child.getBottom());
if (Rect.intersects(rect1, rect2)) {
return child;
}
}
}
return null;
}
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
LinearLayoutManager linearLayoutManager =
(LinearLayoutManager) recyclerView.getLayoutManager();
if (mCenterPivot == 0) {
mCenterPivot = recyclerView.getLeft() + recyclerView.getRight();
}
if (!mAutoSet) {
synchronized (this) {
if (newState == RecyclerView.SCROLL_STATE_IDLE) {
View view = linearLayoutManager.findViewByPosition(mPosition);
mPosition = INITIAL_POSITION;
if (view == null) {
view = findCenterView(linearLayoutManager);
}
int viewCenter = (view.getLeft() + view.getRight()) / 2;
int viewWidth = view.getRight() - view.getLeft();
int scrollNeeded = viewCenter - mCenterPivot;
if (BuildConfig.DEBUG)
Log.d(
TAG,
"viewCentre = "
+ viewCenter
+ " viewWidth = "
+ viewWidth
+ " scrollNeeded = "
+ scrollNeeded
+ " recyclerViewWidth = "
+ recyclerView.getMeasuredWidth());
recyclerView.smoothScrollBy(scrollNeeded, 0);
mCenterHolderPosition = recyclerView.getChildLayoutPosition(view);
if (BuildConfig.DEBUG)
Log.d(
TAG,
"centerHolderPosition = " + mCenterHolderPosition + " mPosition = " + mPosition);
if (mScrollType == null) {
mScrollType = SwipeType.SWIPE;
}
onCenterItemSnap(
mCenterHolderPosition, recyclerView.getChildViewHolder(view), mScrollType);
mScrollType = null;
mAutoSet = true;
}
}
}
if (newState == RecyclerView.SCROLL_STATE_DRAGGING
|| newState == RecyclerView.SCROLL_STATE_SETTLING) {
mAutoSet = false;
}
}
