当ListView子标题在上面滚动时更改ListView标题文本

Question

我在Android应用程序中工作，我有一个带有子标题的ListView和该子标题内的项目。我正在使用海关清单视图来实现这一点。现在，当下面的子标题滚动到ListView上方时，我想替换顶部子标题文本。 Android LinkedIn中也实现了相同的功能。

以下是我的Adapter类：

import java.util.ArrayList;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Filter;
import android.widget.Filterable;
import android.widget.TextView;

import com.evero.android.domain.Consumer;

/**
 * @author Arun PS
 * 
 */
public class CaseManagerAdaptor extends BaseAdapter implements Filterable {

    private ValueFilter valueFilter = null;

    private ArrayList<Consumer> mData = new ArrayList<Consumer>();
    private ArrayList<Consumer> mDatabackup = new ArrayList<Consumer>();
    private LayoutInflater mInflater;

    public CaseManagerAdaptor(Context context, ArrayList<Consumer> consumers) {

        mInflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        mData = mDatabackup = consumers;

        getFilter();
    }

    @Override
    public int getCount() {
        return mDatabackup.size();
    }

    @Override
    public String getItem(int position) {
        return mData.get(position).toString();
    }

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

    public static class ViewHolder {
        public TextView textView1 = null;
        public TextView textView2 = null;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;

        holder = new ViewHolder();
        if (!mDatabackup.get(position).IsHeader) {
            convertView = mInflater.inflate(R.layout.subhead_listitem, null);
            holder.textView1 = (TextView) convertView
                    .findViewById(R.id.clientname_textView);
            holder.textView2 = (TextView) convertView
                    .findViewById(R.id.serviceCompletedCount_textView);

        } else {

            convertView = mInflater.inflate(R.layout.head_list_item, null);
            holder.textView1 = (TextView) convertView
                    .findViewById(R.id.head_list_Text);
        }

        if (mDatabackup.get(position).IsHeader)

            holder.textView1.setText(mDatabackup.get(position).EmployeeName);

        else {
            convertView.setTag(mDatabackup.get(position));
            holder.textView1.setText(mDatabackup.get(position).ClientName);
            holder.textView2
                    .setText(mDatabackup.get(position).ServiceCompletedCount);
        }

        return convertView;
    }

    // Returns a filter that can be used to constrain data with a filtering
    // pattern.
    @Override
    public Filter getFilter() {

        if (valueFilter == null) {

            valueFilter = new ValueFilter();
        }

        return valueFilter;
    }

    private Boolean isFiltered = null;

    private class ValueFilter extends Filter {

        // Invoked in a worker thread to filter the data according to the
        // constraint.
        @Override
        protected FilterResults performFiltering(CharSequence constraint) {
            isFiltered = false;

            FilterResults results = new FilterResults();

            if (constraint != null && constraint.length() > 0) {

                ArrayList<Consumer> filterList = new ArrayList<Consumer>();

                for (int i = 0; i < mData.size(); i++) {

                    if (!mData.get(i).IsHeader
                            && mData.get(i).ClientName.startsWith(constraint
                                    .toString())) {

                        filterList.add(mData.get(i));

                    }
                }

                results.count = filterList.size() + 1;

                results.values = filterList;

                isFiltered = true;
            } else {

                results.count = mData.size();

                results.values = mData;

            }

            return results;
        }

        @SuppressWarnings("unchecked")
        @Override
        protected void publishResults(CharSequence constraint,
                FilterResults results) {

            mDatabackup = (ArrayList<Consumer>) results.values;
            if (isFiltered && mData.size() > mDatabackup.size()) {
                Consumer consumer = new Consumer();
                consumer.IsHeader = true;
                consumer.EmployeeName = (mDatabackup.size() == 0 ? "No record found"
                        : "Individual");
                consumer.ClientName = "";
                mDatabackup.add(0, consumer);
            }

            notifyDataSetChanged();

        }

    }

}