PinnedHeaderExpListView. Check it out here: http://stackoverflow.com/questions/10613552/pinned-groups-in-expandablelistview

PinnedHeaderAdapter.java

package me.pcqpcq.android.widget;

import android.view.View;

/**
 * Adapter interface.  The list adapter must implement this interface.
 *
 * @see <a href="http://stackoverflow.com/questions/10613552/pinned-groups-in-expandablelistview">source</a>
 */
public interface PinnedHeaderAdapter {

    /**
     * Pinned header state: don't show the header.
     */
    public static final int PINNED_HEADER_GONE = 0;

    /**
     * Pinned header state: show the header at the top of the list.
     */
    public static final int PINNED_HEADER_VISIBLE = 1;

    /**
     * Pinned header state: show the header. If the header extends beyond
     * the bottom of the first shown element, push it up and clip.
     */
    public static final int PINNED_HEADER_PUSHED_UP = 2;

    /**
     * Configures the pinned header view to match the first visible list item.
     *
     * @param header   pinned header view.
     * @param position position of the first visible list item.
     * @param alpha    fading of the header view, between 0 and 255.
     */
    void configurePinnedHeader(View header, int position, int alpha);
}

PinnedHeaderExpListAdapter.java

package me.pcqpcq.android.widget;

import android.widget.AbsListView;
import android.widget.BaseExpandableListAdapter;

/**
 * A simple adapter which maintains an ArrayList of photo resource Ids.
 * Each photo is displayed as an image. This adapter supports clearing the
 * list of photos and adding a new photo.
 *
 * @see <a href="http://stackoverflow.com/questions/10613552/pinned-groups-in-expandablelistview">source</a>
 */
public abstract class PinnedHeaderExpListAdapter extends BaseExpandableListAdapter implements PinnedHeaderAdapter, AbsListView.OnScrollListener {

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        return true;
    }

    @Override
    public boolean hasStableIds() {
        return true;
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        if (view instanceof PinnedHeaderExpListView) {
            ((PinnedHeaderExpListView) view).configureHeaderView(firstVisibleItem);
        }
    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
    }

}

PinnedHeaderExpListView.java

package me.pcqpcq.android.widget;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.View;
import android.widget.ExpandableListAdapter;
import android.widget.ExpandableListView;

/**
 * A ListView that maintains a header pinned at the top of the list. The
 * pinned header can be pushed up and dissolved as needed.
 *
 * @see <a href="http://stackoverflow.com/questions/10613552/pinned-groups-in-expandablelistview">source</a>
 */
public class PinnedHeaderExpListView extends ExpandableListView {

    private static final int MAX_ALPHA = 255;

    private PinnedHeaderExpListAdapter mAdapter;
    private View mHeaderView;
    private boolean mHeaderViewVisible;

    private int mHeaderViewWidth;

    private int mHeaderViewHeight;

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

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

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

    public void setPinnedHeaderView(View view) {
        mHeaderView = view;

        // Disable vertical fading when the pinned header is present
        // TODO change ListView to allow separate measures for top and bottom fading edge;
        // in this particular case we would like to disable the top, but not the bottom edge.
        if (mHeaderView != null) {
            setFadingEdgeLength(0);
        }
        requestLayout();
    }

    @Override
    public void setAdapter(ExpandableListAdapter adapter) {
        super.setAdapter(adapter);
        mAdapter = (PinnedHeaderExpListAdapter)adapter;
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        if (mHeaderView != null) {
            measureChild(mHeaderView, widthMeasureSpec, heightMeasureSpec);
            mHeaderViewWidth = mHeaderView.getMeasuredWidth();
            mHeaderViewHeight = mHeaderView.getMeasuredHeight();
        }
    }

    @Override
    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        if (mHeaderView != null) {
            mHeaderView.layout(0, 0, mHeaderViewWidth, mHeaderViewHeight);
            configureHeaderView(getFirstVisiblePosition());
        }
    }

    /** 
     * animating header pushing
     * @param position
     */
    public void configureHeaderView(int position) {
        final int group = getPackedPositionGroup(getExpandableListPosition(position));
        int groupView = getFlatListPosition(getPackedPositionForGroup(group));

        if (mHeaderView == null) {
            return;
        }
        // init header
        mAdapter.configurePinnedHeader(mHeaderView, group, 0);

        mHeaderView.setOnClickListener(new OnClickListener() {

            public void onClick(View header) {
                if(!expandGroup(group)) collapseGroup(group); 
            }
        }); 

        int state,nextSectionPosition = getFlatListPosition(getPackedPositionForGroup(group+1));

        if (mAdapter.getGroupCount()== 0) {
            state = PinnedHeaderAdapter.PINNED_HEADER_GONE;
        }else if (position < 0) {
            state = PinnedHeaderAdapter.PINNED_HEADER_GONE;
        }else if (nextSectionPosition != -1 && position == nextSectionPosition - 1) {
            state=PinnedHeaderAdapter.PINNED_HEADER_PUSHED_UP;
        }else  state=PinnedHeaderAdapter.PINNED_HEADER_VISIBLE;

        switch (state) {    
            case PinnedHeaderAdapter.PINNED_HEADER_GONE: {
                mHeaderViewVisible = false;
                break;
            }

            case PinnedHeaderAdapter.PINNED_HEADER_VISIBLE: {
                mAdapter.configurePinnedHeader(mHeaderView, group, MAX_ALPHA);
                if (mHeaderView.getTop() != 0) {
                    mHeaderView.layout(0, 0, mHeaderViewWidth, mHeaderViewHeight);
                }
                mHeaderViewVisible = true;
                break;
            }

            case PinnedHeaderAdapter.PINNED_HEADER_PUSHED_UP: {
                View firstView = getChildAt(0);
                if(firstView==null){
                    if (mHeaderView.getTop() != 0) {
                        mHeaderView.layout(0, 0, mHeaderViewWidth, mHeaderViewHeight);
                    }
                    mHeaderViewVisible = true;
                    break;
                }
                int bottom = firstView.getBottom();
                int itemHeight = firstView.getHeight();
                int headerHeight = mHeaderView.getHeight();
                int y;
                int alpha;
                if (bottom < headerHeight) {
                    y = (bottom - headerHeight);
                    alpha = MAX_ALPHA * (headerHeight + y) / headerHeight;
                } else {
                    y = 0;
                    alpha = MAX_ALPHA;
                }
                mAdapter.configurePinnedHeader(mHeaderView, group, alpha);
                //выползание
                if (mHeaderView.getTop() != y) {
                    mHeaderView.layout(0, y, mHeaderViewWidth, mHeaderViewHeight + y);
                }
                mHeaderViewVisible = true;
                break;
            }
        }
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        super.dispatchDraw(canvas);
        if (mHeaderViewVisible) {
            drawChild(canvas, mHeaderView, getDrawingTime());
        }
    }

}