Expandable View layout_height must be fixed.

[nathanielwolf]

This does not function when using wrap_content for the layout_height of the collapsable view. The animator cannot get a proper value for mEndHeight because the view has not been laid out yet.

[tjerkw]

Yes indeed that is a problem currently. Do you have an idea how to solve this?

[nathanielwolf]

I solved this problem, and the problem of randomly expanded views as result of view recycling in the Adapter.

public class MyListAdapter extends ArrayAdapter<MyObject> 

    int[] mCollapsableHeights;
    boolean[] mOpenned;

    public WhyPuursAdapter(Context context,
            List<WhyPuur> objects) {
        super(context, 0, objects);
        mCollapsableHeights = new int[objects.size()];
        mOpenned = new boolean[objects.size()];
    }

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    final View view = convertView;
    final View collapsable = view.findViewById(R.id.row_whypure_collapsable);

    //measure only once - hide expanded views by returning false in onPreDraw()
    if(mCollapsableHeights[position] == 0){
        view.getViewTreeObserver().addOnPreDrawListener(
            new OnPreDrawListener(){
                @Override
                public boolean onPreDraw() {
                    view.getViewTreeObserver().removeOnPreDrawListener(this);
                    mTextHeights[position] = collapsable.getHeight();
                    setCollapsedView(collapsable, position);
                    return false;
                }
            });

    } else 
            setCollapsedView(collapsable, position);

    view.setOnClickListener(new OnClickListener(){
            @Override
            public void onClick(View v) {

                mOpenned[position] = !mOpenned[position];
                ExpandAnimation newAnim = new ExpandAnimation(collapsable, 300);
                collapsable.startAnimation(newAnim);
            }
        });

    return view;    
}

/*
* Set visibility of collapsed view
*/
public void setCollapsedView(View collapsable, int position){

        final LinearLayout.LayoutParams params = (LinearLayout.LayoutParams)collapsable.getLayoutParams();
        if(!mOpenned[position] ){
            collapsable.setVisibility(View.GONE);
            params.bottomMargin = 0-mTextHeights[position];
        }else{
            collapsable.setVisibility(View.VISIBLE);
            params.bottomMargin = 0;
        }
        collapsable.setLayoutParams(params);
    }
}

[myrmidon-media]

I solved it like this:

public ExpandCollapseAnimation(View view, int duration, int type) {

        setDuration(duration);
        mAnimatedView = view;
        //Force Measure with unspecified specs
        mAnimatedView.measure(0, 0);
        //Get Measured Height
        mEndHeight = mAnimatedView.getMeasuredHeight();
        //mEndHeight = mAnimatedView.getLayoutParams().height;
        mLayoutParams = ((LinearLayout.LayoutParams) view.getLayoutParams());
        mType = type;
        if(mType == EXPAND) {

            mLayoutParams.bottomMargin = -mEndHeight;
        } else {

            mLayoutParams.bottomMargin = 0;
        }
        view.setVisibility(View.VISIBLE);
    }

[tjerkw]

Hey @nathanielwolf thanks, thats a smart solution. B.t.w. the problem randomly expanded views is just solved in the current master. So that should be fixed now.

For now i'm going to test the solution by @gorilla-maguila

[tjerkw]

@gorilla-maguila your solution does not have the correct measured height for the /sample project. Hmmz i'm going to look for the proper generic solution.

[myrmidon-media]

what's giving you getMeasuredHeight() ? In my project works great the above solution.

[tjerkw]

Issue #6 was related.

I think I tackled it. I solved it by using the OnPreDrawListener and setCollapseView method as @nathanielwolf suggested, smart move btw! However I also updated the ExpandCollapseAnimation to use getHeight instead of the LinearLayout height.

My commit: https://github.com/tjerkw/Android-SlideExpandableListView/commit/4a79ddfa7f5a19c6ae93d8cfbc53429627566eae

B.t.w. the only thing that I dislike is the Map<Integer, Integer> that now has an entry for every item in the list. If the list grows to 1000 items, it means a lot of extra memory is needed. But I don't see a nice solution for you.

@nathanielwolf @gorilla-maguila @grivos could you all confirm that this commit fixes the problem?

Thanks in Advance!! Coudn't do it without your ideas!

[grivos]

Looks good. Nice work!

However, There is a problem if the data set is changed and the current state is invalid. You might want to make WrapperListAdapterImpl extend BaseAdapter, and then in AbstractSlideExpandableListAdapter - override notifyDataSetChanged() and reset the state there.

[tjerkw]

I thought of that problem too. Wanted to solve it with:

registerDataSetObserver(new DataSetObserver() { ... }

However If a user of the library would set its own datasetobserver it would break my listener. Since only one listener is allowed.

I think your solution is the correct one. It should also override notifyDataSetInvalidated() in that case.

Will look at this later.

[tjerkw]

Created issue #11, closed this one.