Question

I have a custom configuration page in my app which just so happens to contain a ListView which you can select/deselect, edit, add to and remove items from. Since the amount of configuration is so large I’ve had to put it all in a ScrollView

My problem is of course that you cannot have scroll functionality within a view which already has it’s own scroll functionality. This means I can’t have a scrolling ListView inside a ScrollView.

What I’ve been trying to do is find the best way of limiting the damage this does. I’ve seen suggestions that say “You could just create a LinearLayout which grows as you add more children”. That would work find by the added effort required to plug in the selectable nature, the reordering & sorting of the list as well as the editing would be a maintanance nightmare.

I’ve spent the day trying to find a way of measuring the height of each ListView item. Once I can find the size of each item (not just the content but any padding and space between items) on each device I know I can simply change the height of the ListView per item added.

Unfortunately I can’t seem to find a way to reliably pull back the height of a listviews child.

(The old chestnut of using a GlobalLayoutListener doesn’t help me pull back the padding between items)

final TextView listLabel = (TextView) toReturn.findViewById(R.id.listLabel);
final ViewTreeObserver vto = listLabel.getViewTreeObserver();
vto.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

    @Override
    public void onGlobalLayout() {
        listLabel.getViewTreeObserver().removeGlobalOnLayoutListener(this);
        mListItemHeight = listLabel.getHeight();
    }
});

Answer 1

EDIT

Expanding ListView’s are you’re friend – This LinearLayout expands based on it’s content. It allows Dynamic ListView‘s inside of ScrollView.

public class LinearListView extends LinearLayout {

    private BaseAdapter mAdapter;
    private Observer mObserver;
    private OnItemClickListener mOnItemClickListener;
    private OnItemLongClickListener mOnItemLongClickListener;

    public LinearListView(Context context) {
        super(context);
        init();
    }

    public LinearListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public LinearListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    private void init() {
        mObserver = new Observer();
    }

    public void setAdapter(BaseAdapter adapter) {
        if (this.mAdapter != null)
            this.mAdapter.unregisterDataSetObserver(mObserver);

        this.mAdapter = adapter;
        adapter.registerDataSetObserver(mObserver);
        mObserver.onChanged();
    }

    public void setOnItemClickListener(OnItemClickListener listener) {
        mOnItemClickListener = listener;
    }

    public void setOnItemLongClickListener(OnItemLongClickListener listener) {
        mOnItemLongClickListener = listener;
    }

    private int mListSelector = R.drawable.selector_list;
    public void setListSelector(int resid) {
        mListSelector = resid;
    }

    private class Observer extends DataSetObserver {
        public Observer(){}

        @Override
        public void onChanged() {
            List<View> oldViews = new ArrayList<View>(getChildCount());

            for (int i = 0; i < getChildCount(); i++)
                oldViews.add(getChildAt(i));

            Iterator<View> iter = oldViews.iterator();

            removeAllViews();

            for (int i = 0; i < mAdapter.getCount(); i++) {
                final int index = i;
                View convertView = iter.hasNext() ? iter.next() : null;
                View toAdd = mAdapter.getView(i, convertView, LinearListView.this);
                toAdd.setBackgroundResource(mListSelector);
                toAdd.setOnClickListener(new OnClickListener() {

                    @Override
                    public void onClick(View v) {
                        if(mOnItemClickListener != null) {
                            mOnItemClickListener.onItemClick(null, v, index, index);
                        }
                    }
                });
                toAdd.setOnLongClickListener(new OnLongClickListener() {

                    @Override
                    public boolean onLongClick(View v) {
                        if(mOnItemLongClickListener != null) {
                            mOnItemLongClickListener.onItemLongClick(null, v, index, index);
                        }
                        return true;
                    }                   
                });
                LinearListView.this.addView(toAdd, new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
            }
            super.onChanged();
        }

        @Override
        public void onInvalidated() {
            removeAllViews();
            super.onInvalidated();
        }
    }
}