GridAndListLayout.java

public class GridAndListLayout extends TWAbsLayoutManager {
    private final int NUM_LANES = 2;

    public GridAndListLayout(Context context, Orientation orientation) {
        super(context, orientation);
    }

    private boolean isVertical() {
        return (getOrientation() == Orientation.VERTICAL);
    }

    private boolean isGridItem(int position) {
        return position < 4;
    }

    private int getLaneForPosition(int position) {
        if (isGridItem(position)) {
            return position % NUM_LANES;
        }

        return 0;
    }

    private int getLayoutInnerStart() {
        final View firstChild = getChildAt(0);
        final int firstPosition = getPosition(firstChild);

        final int offset;
        if (getLaneForPosition(firstPosition) > 0) {
            if (isVertical()) {
                offset = getDecoratedMeasuredHeight(firstChild);
            } else {
                offset = getDecoratedMeasuredWidth(firstChild);
            }
        } else {
            offset = 0;
        }

        return getLayoutStart() + offset;
    }

    private int getLayoutInnerEnd() {
        final View lastChild = getChildAt(getChildCount() - 1);
        final int lastPosition = getPosition(lastChild);

        final int offset;
        if (isGridItem(lastPosition) && getLaneForPosition(lastPosition) < NUM_LANES - 1) {
            if (isVertical()) {
                offset = getDecoratedMeasuredHeight(lastChild);
            } else {
                offset = getDecoratedMeasuredWidth(lastChild);
            }
        } else {
            offset = 0;
        }

        return getLayoutEnd() - offset;
    }

    /* This method will become optional soon. */
    @Override
    protected int getLayoutStart() {
        final View child = getChildAt(0);
        if (child != null) {
            return (isVertical() ? getDecoratedTop(child) : getDecoratedLeft(child));
        }

        return 0;
    }

    /* This method will become optional soon. */
    @Override
    protected int getLayoutEnd() {
        final View child = getChildAt(getChildCount() - 1);
        if (child != null) {
            return (isVertical() ? getDecoratedBottom(child) : getDecoratedRight(child));
        }

        return 0;
    }

    @Override
    protected void measureChild(View child) {
        int widthUsed = 0;
        int heightUsed = 0;

        if (isGridItem(getPosition(child))) {
            if (isVertical()) {
                widthUsed = (getWidth() - getPaddingLeft() - getPaddingRight()) / 2;
            } else {
                heightUsed = (getHeight() - getPaddingTop() - getPaddingBottom()) / 2;
            }
        }

        measureChildWithMargins(child, widthUsed, heightUsed);
    }

    @Override
    protected void layoutChild(View child, Direction direction) {
        final int width = getDecoratedMeasuredWidth(child);
        final int height = getDecoratedMeasuredHeight(child);

        final int position = getPosition(child);
        final int gridLane = getLaneForPosition(position);

        final boolean isVertical = isVertical();
        final boolean isGridItem = isGridItem(position);

        final int gridOffset;
        if (isGridItem) {
            gridOffset = (isVertical ? width : height) * gridLane;
        } else {
            gridOffset = 0;
        }

        int l, t, r, b;
        if (isVertical) {
            l = getPaddingLeft() + gridOffset;
            t = direction == Direction.END ? getLayoutEnd() : getLayoutStart() - height;
        } else {
            l = direction == Direction.END ? getLayoutEnd() : getLayoutStart() - width;
            t = getPaddingTop() + gridOffset;
        }

        if (isGridItem) {
            if (direction == Direction.END && gridLane > 0) {
                if (isVertical()) {
                    t -= height;
                } else {
                    l -= width;
                }
            } else if (direction == Direction.START && gridLane < NUM_LANES - 1) {
                if (isVertical()) {
                    t += height;
                } else {
                    l += width;
                }
            }
        }

        r = l + width;
        b = t + height;

        layoutDecorated(child, l, t, r, b);
    }

    @Override
    protected void detachChild(View child, Direction direction) {
        // No need to do anything.
    }

    @Override
    protected boolean canAddMoreViews(Direction direction, int limit) {
        if (direction == Direction.END) {
            return getLayoutInnerEnd() < getEndWithPadding();
        } else {
            return getLayoutInnerStart() > getStartWithPadding();
        }
    }