Merge "Use scrollToPositionWithOffset in widget list and account for padding" into sc-dev

import android.util.Log;

import android.util.SparseArray;

import android.view.LayoutInflater;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.View.OnLongClickListener;

import android.view.ViewGroup;

import androidx.annotation.NonNull;

import androidx.annotation.Nullable;

import androidx.recyclerview.widget.LinearLayoutManager;

import androidx.recyclerview.widget.RecyclerView;

import androidx.recyclerview.widget.RecyclerView.Adapter;

import androidx.recyclerview.widget.RecyclerView.ViewHolder;

            updateVisibleEntries();

            // Scroll the layout manager to the header position to keep it anchored to the same

            // position.

            scrollToSelectedHeaderPosition();

            scrollToPositionAndMaintainOffset(getSelectedHeaderPosition());

        } else if (packageUserKey.equals(mWidgetsContentVisiblePackageUserKey)) {

            OptionalInt previouslySelectedPosition = getSelectedHeaderPosition();

            mWidgetsContentVisiblePackageUserKey = null;

            updateVisibleEntries();

            // Scroll to the header that was just collapsed so it maintains its scroll offset.

            scrollToPositionAndMaintainOffset(previouslySelectedPosition);

        }

    }

    private void scrollToSelectedHeaderPosition() {

        OptionalInt selectedHeaderPosition =

                IntStream.range(0, mVisibleEntries.size())

    private OptionalInt getSelectedHeaderPosition() {

        return IntStream.range(0, mVisibleEntries.size())

                .filter(index -> isHeaderForVisibleContent(mVisibleEntries.get(index)))

                .findFirst();

        RecyclerView.LayoutManager layoutManager =

                mRecyclerView == null ? null : mRecyclerView.getLayoutManager();

        if (!selectedHeaderPosition.isPresent() || layoutManager == null) {

            return;

    }

        // Scroll to the selected header position. LinearLayoutManager scrolls the minimum distance

        // necessary, so this will keep the selected header in place during clicks, without

        // interrupting the animation.

        int position = selectedHeaderPosition.getAsInt();

        if (position == mVisibleEntries.size() - 2) {

            // If the selected header is in the last position (-1 for the content), then scroll to

            // the final position so the last list of widgets will show.

    /**

     * Scrolls to the selected header position. LinearLayoutManager scrolls the minimum distance

     * necessary, so this will keep the selected header in place during clicks, without interrupting

     * the animation.

     */

    private void scrollToPositionAndMaintainOffset(OptionalInt positionOptional) {

        if (!positionOptional.isPresent() || mRecyclerView == null) return;

        int position = positionOptional.getAsInt();

        LinearLayoutManager layoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();

        if (layoutManager == null) return;

        if (position == mVisibleEntries.size() - 2

                && mVisibleEntries.get(mVisibleEntries.size() - 1)

                instanceof WidgetsListContentEntry) {

            // If the selected header is in the last position and its content is showing, then

            // scroll to the final position so the last list of widgets will show.

            layoutManager.scrollToPosition(mVisibleEntries.size() - 1);

        } else {

            // Otherwise, scroll to the position of the selected header.

            layoutManager.scrollToPosition(position);

            return;

        }

        // Scroll to the header view's current offset, accounting for the recycler view's padding.

        // If the header view couldn't be found, then it will appear at the top of the list.

        View headerView = layoutManager.findViewByPosition(position);

        int targetHeaderViewTop =

                headerView == null ? 0 : layoutManager.getDecoratedTop(headerView);

        layoutManager.scrollToPositionWithOffset(

                position,

                targetHeaderViewTop - mRecyclerView.getPaddingTop());

    }

    /**