listview使用checkbox批量删除出现的问题

1.选中前面的checkbox导致后的checkbox被选中

2.选中后下滑listview，再上滑时被选中的checkbox又变成未选中状态。

问题大都是因为对listview进行代码优化重用convertView导致的。

解决方法：

package se08.edu.com.example.hxdn.softwareengineeringdate;

import android.content.Context;
import android.support.annotation.NonNull;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 * Created by hxdn on 2015/9/27.
 */
class MyAdapter extends BaseAdapter {
    private Context mcontext;
    private int pagesize=15;
    private int page=1;
    private LayoutInflater inflater=null;
    private Person person[];
   // private static ArrayList<String> selected;
    private Map<Integer,String> selected;
    public MyAdapter(Context c,Person p[],int page,int pagesize)
    {
        this.mcontext=c;
        this.person=p;
        this.page=page;
        this.pagesize=pagesize;
        this.inflater=LayoutInflater.from(c);
        selected = new HashMap<Integer,String>();
    }
    public Map<Integer,String> getSelected()
    {
        return selected;
    }
    @Override
    public int getCount() {
        int c=(page-1)*pagesize;
        if (person.length-c<pagesize)
        {
            return person.length-c;
        }
        else
        {
            return pagesize;
        }

    }

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

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder=null;
        selected = new HashMap<Integer,String>();
        if (convertView==null)
        {
            viewHolder=new ViewHolder();
            convertView=inflater.inflate(R.layout.simple_item,parent,false);
            viewHolder.iv=(ImageView)convertView.findViewById(R.id.iv);
            viewHolder.name=(TextView)convertView.findViewById(R.id.name);
            viewHolder.majorId=(TextView)convertView.findViewById(R.id.majorId);
            viewHolder.tel=(TextView)convertView.findViewById(R.id.tel);
            viewHolder.cb=(CheckBox)convertView.findViewById(R.id.check);
            convertView.setTag(viewHolder);
        }
        else
        {

            viewHolder=(ViewHolder)convertView.getTag();
        }
        viewHolder.cb.setTag(position + pagesize * (page - 1));//设置标签
        if (selected.containsKey(position + pagesize * (page - 1)))
        //判断listview的item上的checkbox是否被选中,用position+pagesize*(page-1)作为唯一标识
        {
            viewHolder.cb.setChecked(true);
        }
        else
        {
            viewHolder.cb.setChecked(false);
        }
        if (MainActivity.editModel)
        {
            viewHolder.cb.setVisibility(View.VISIBLE);
        }
        else
        {
            viewHolder.cb.setVisibility(View.GONE);
        }
        viewHolder.iv.setImageResource(person[position + pagesize * (page - 1)].getImageId());
        viewHolder.name.setText(person[position + pagesize * (page - 1)].getName());
        viewHolder.tel.setText(person[position + pagesize * (page - 1)].getTel());
        viewHolder.majorId.setText(person[position + pagesize * (page - 1)].getMajorId());
        viewHolder.cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        //OnCheckChangedListener监听CheckBox的状态，无论来自你的onClick事件还是其他。
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                if (isChecked)
                {
                    if(!selected.containsKey(buttonView.getTag()))
                    //前面代码进行优化,会对converView进行复用,所以会导致当前面一个checkbox被选中后面的checkbox也被选中
                    //于是进行判断,如果selectd没有这个key值，则加入到selectd中
                    //之前出现的问题是当我选中第一个checkbox，第十二个也会被选中
                    // 加了这个判断后，即使第十二checkbox是因为复用converView导致被选中的,但selectd的key值已经包含了
                    //这个信息，selectd便不会将其加入。
                    //在前面用selectd进行判断的时候便会把第十二checkbox设置为false；
                        selected.put((Integer) buttonView.getTag(),person[position + pagesize * (page - 1)].getMajorId());
                    MainActivity.txtcount.setText("共选中:" + selected.size());
                }
                else
                {
                    selected.remove((Integer) buttonView.getTag());
                    MainActivity.txtcount.setText("共选中:" + selected.size());
                }
            }
        });
        return convertView;
    }
    public class ViewHolder
    {
        private ImageView iv;
        private TextView name;
        private TextView majorId;
        private TextView tel;
        CheckBox cb;
    }
}