Android中listview和imageview实现条目单选效果

public class MainActivity extends ActionBarActivity implements OnItemClickListener {
 private ListAdapter adapter;
 private ListView listview;
 private List list=new ArrayList();
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  requestWindowFeature(Window.FEATURE_NO_TITLE);
  setContentView(R.layout.activity_main);
  initView();

 }

 private void initView() {
  listview = (ListView) findViewById(R.id.listview);
  addData();
  adapter=new ListAdapter(MainActivity.this);
  listview.setAdapter(adapter);
  listview.setOnItemClickListener(this);

 }
 private void addData() {
  for (int i = 0; i <20; i++) {
   list.add("深圳"+i);
  }
 }
 class ListAdapter extends BaseAdapter{
  private int selectedPosition = -1;// 选中的位置
  private Context context;  
  public ListAdapter(Context context) {
   this.cOntext= context;
  }

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

  @Override
  public Object getItem(int position) {
   return list.get(position);
  }
  public void setSelectedPosition(int position) {
   selectedPosition = position;
  }
  @Override
  public long getItemId(int position) {
   return position;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   ViewHolder holder;
   if (cOnvertView==null) {
    holder=new ViewHolder();
    cOnvertView=LayoutInflater.from(context).inflate(R.layout.listview_item, null);
    holder.tv=(TextView) convertView.findViewById(R.id.tv);
    holder.iv=(ImageView) convertView.findViewById(R.id.iv);

    convertView.setTag(holder);
   }else{
    holder=(ViewHolder) convertView.getTag();
   }
   String string = list.get(position);
   holder.tv.setText(string);
   if(position%2==0){
    if (selectedPosition==position) {
     convertView.setSelected(true);
     convertView.setPressed(true);
//     convertView.setBackgroundColor(Color.parseColor("#0097e0"));
     holder.iv.setImageResource(R.drawable.sex_down);
    }else{
     convertView.setSelected(false);
     convertView.setPressed(false);
//     convertView.setBackgroundColor(Color.parseColor("#e4ebf1"));
     holder.iv.setImageResource(R.drawable.sex_nor);
    } 
   }else{
    if (selectedPosition==position) {
     convertView.setSelected(true);
     convertView.setPressed(true);
     holder.iv.setImageResource(R.drawable.sex_down);
//     convertView.setBackgroundColor(Color.parseColor("#0097e0"));
    }else{
     convertView.setSelected(false);
     convertView.setPressed(false);
//     convertView.setBackgroundColor(Color.parseColor("#ced7de"));
     holder.iv.setImageResource(R.drawable.sex_nor);
    }
   }
   return convertView;
  }
  class ViewHolder{
   TextView tv;
   ImageView iv;
  }
 }
 @Override
 public void onItemClick(AdapterView<&＃63;> parent, View view, int position, long id) {
  adapter.setSelectedPosition(position);
  adapter.notifyDataSetInvalidated();
 }
}