ListView in BottomSheet

Question

I ran into a problem where I had a simple ListView in a BottomSheet and ListView had enough items to fill the screen and scroll even m

Answer 1

I have tried Nested ListViews that was described here, but they do not allow expand /collapse bottom sheet when touching on ListView. Below is my solution, when you scroll up and ListView cannot scroll up, bottom sheet will be expanded, when you scroll down and ListView cannot do it, BottomSheet will be collapsed.

public class NestedListView extends ListView {

    private boolean mIsBeingDragged = false;
    private float mLastMotionY;

    public NestedListView(final Context context, final AttributeSet attrs) {
        super(context, attrs);
    }

    public NestedListView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        switch (event.getActionMasked()) {
            case MotionEvent.ACTION_DOWN: {
                if (canScrollDown() || canScrollUp()) {
                    final ViewParent parent = getParent();
                    if (parent != null) {
                        parent.requestDisallowInterceptTouchEvent(true);
                    }
                }
                break;
            }
        }
        return super.onInterceptTouchEvent(event);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        final float y = event.getRawY();

        switch (event.getActionMasked()) {
            case MotionEvent.ACTION_MOVE: {
                if (!mIsBeingDragged) {
                    final float deltaY = mLastMotionY - y;
                    mIsBeingDragged = (deltaY > 0 && canScrollDown())
                        || (deltaY < 0 && canScrollUp());

                    if (mIsBeingDragged) {
                        final ViewParent parent = getParent();
                        if (parent != null) {
                            parent.requestDisallowInterceptTouchEvent(true);
                        }
                    } else {
                        final ViewParent parent = getParent();
                        if (parent != null) {
                            parent.requestDisallowInterceptTouchEvent(false);
                        }
                        return false;
                    }
                }
            }

            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
                mIsBeingDragged = false;
                break;
        }

        mLastMotionY = y;

        return super.onTouchEvent(event);
    }

    public boolean canScrollUp() {
        final int childCount = getChildCount();
        if (childCount == 0) {
            return false;
        }

        final int firstPosition = getFirstVisiblePosition();
        final int firstTop = getChildAt(0).getTop();
        return firstPosition > 0 || firstTop < getListPaddingTop();
    }

    public boolean canScrollDown() {
        final int childCount = getChildCount();
        if (childCount == 0) {
            return false;
        }

        final int firstPosition = getFirstVisiblePosition();
        final int lastBottom = getChildAt(childCount - 1).getBottom();
        final int lastPosition = firstPosition + childCount;
        return lastPosition < getCount() || lastBottom > getHeight() - getListPaddingBottom();
    }
}