Question

I have the following code that make the ListView appears like a Vertical Gallery

public class VerticalGallery extends ListView {
    private View currentDisplayingView;
    private int currentPosition;

    public VerticalGallery(Context context, List<Page> pages) {
            super(context);

        setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                currentDisplayingView = view;
                currentPosition = position;
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
            }
        });

        setAdapter(new PageAdapter(context, pages));

        setCacheColorHint(Color.TRANSPARENT);
    }

    public boolean onTouchEvent(MotionEvent evt) {
        if (currentDisplayingView != null && currentDisplayingView.onTouchEvent(evt))
            return true;

        PageAdapter adapter = (PageAdapter) getAdapter();

        if (currentPosition == adapter.list.size() - 1)
            return false;

        // TODO: Handle events and swipe somewhere
        return super.onTouchEvent(evt);
    }

    public class PageAdapter extends BaseAdapter {
        private Context context;
        private List<Page> list;

        public PageAdapter(Context c, List<Page> pages) {
            context = c;
            list = pages;
        }

        public int getCount() {
            return list.size();
        }

        public Page getItem(int position) {
            return list.get(position);
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
            View view = getItem(position).generateView(context);
            view.setLayoutParams(new ListView.LayoutParams(LayoutParams.MATCH_PARENT,
                    LayoutParams.MATCH_PARENT));
            return view;
        }
    }    
}

But there’s some behaviors that I need to simulate also:

• Centralize a View:
  When a new view come, I need to centralize it on my display.
• Fire onItemSelected events:
  I need those cause I dispatch events to the current view, and let the ListView scroll only when the currentView returns false on a touchEvent, I don’t need exactly the ItemSelected events, this can be something similar.
• And another question is, if the user swipe up, I should only translate one view (not several according to the speed of the gesture).

Any component that will let me do that will be a usefull answer also.

EDIT:
Actually, I solved this problem with this solution Using Animation to swipe views but I’ll keep this question open.

Answer 1

As I research, I developed this custom ScrollView that does pagination.

public class ScrollViewVertical extends ScrollView {
private boolean paging;

public ScrollViewVertical(Context context) {
    super(context);
}

public boolean onTouchEvent(MotionEvent evt) {
    if (evt.getAction() == MotionEvent.ACTION_UP)
        if (isPaging()){
            centralizeContent();
            return true;
        }

    return super.onTouchEvent(evt);
}

private void centralizeContent() {
    int currentY = getScrollY() + getHeight() / 2;
    ViewGroup content = (ViewGroup) getChildAt(0);
    for (int i = 0; i < content.getChildCount(); i++) {
        View child = content.getChildAt(i);
        System.out.println(BoundsUtils.from(child));
        if (child.getTop() < currentY && child.getBottom() > currentY) {
            smoothScrollTo(0, child.getTop());
            break;
        }
    }
}

}