Android编程之ICS式下拉菜单PopupWindow实现方法详解(附源码下载)

View view = LayoutInflater.from(context).inflate(R.layout.popmenu, null);
popupWindow = new PopupWindow(view, 100, LayoutParams.WRAP_CONTENT);

// 使其聚集
popupWindow.setFocusable(true);
// 设置允许在外点击消失
popupWindow.setOutsideTouchable(true);
//刷新状态（必须刷新否则无效）
popupWindow.update();

// 这个是为了点击“返回Back”也能使其消失，并且并不会影响你的背景（很神奇的） 
popupWindow.setBackgroundDrawable(new BitmapDrawable());
//网上找的我也不知道为什么

package com.tszy.wight;
import java.util.ArrayList;
import android.content.Context;
import android.graphics.drawable.BitmapDrawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.PopupWindow;
import android.widget.TextView;
import com.tszy.watergate.R;
public class PopMenu {
 private ArrayList<String> itemList;
 private Context context;
 private PopupWindow popupWindow ;
 private ListView listView;
 //private OnItemClickListener listener;
 public PopMenu(Context context) {
  // TODO Auto-generated constructor stub
  this.context = context;
  itemList = new ArrayList<String>(5);
  View view = LayoutInflater.from(context).inflate(R.layout.popmenu, null);
  //设置 listview
  listView = (ListView)view.findViewById(R.id.listView);
  listView.setAdapter(new PopAdapter());
  popupWindow = new PopupWindow(view, 100, LayoutParams.WRAP_CONTENT);
  popupWindow = new PopupWindow(view, 
    context.getResources().getDimensionPixelSize(R.dimen.popmenu_width),
    LayoutParams.WRAP_CONTENT);
  // 这个是为了点击“返回Back”也能使其消失，并且并不会影响你的背景（很神奇的）
  popupWindow.setBackgroundDrawable(new BitmapDrawable());
 }
 //设置菜单项点击监听器
 public void setOnItemClickListener(OnItemClickListener listener) {
  //this.listener = listener;
  listView.setOnItemClickListener(listener);
 }
 //批量添加菜单项
 public void addItems(String[] items) {
  for (String s : items)
   itemList.add(s);
 }
 //单个添加菜单项
 public void addItem(String item) {
  itemList.add(item);
 }
 //下拉式 弹出 pop菜单 parent 右下角
 public void showAsDropDown(View parent) {
  popupWindow.showAsDropDown(parent, 10,
    //保证尺寸是根据屏幕像素密度来的
    context.getResources().getDimensionPixelSize(R.dimen.popmenu_yoff));
  // 使其聚集
  popupWindow.setFocusable(true);
  // 设置允许在外点击消失
  popupWindow.setOutsideTouchable(true);
  //刷新状态
  popupWindow.update();
 }
 //隐藏菜单
 public void dismiss() {
  popupWindow.dismiss();
 }
 // 适配器
 private final class PopAdapter extends BaseAdapter {
  @Override
  public int getCount() {
   // TODO Auto-generated method stub
   return itemList.size();
  }
  @Override
  public Object getItem(int position) {
   // TODO Auto-generated method stub
   return itemList.get(position);
  }
  @Override
  public long getItemId(int position) {
   // TODO Auto-generated method stub
   return position;
  }
  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   // TODO Auto-generated method stub
   ViewHolder holder;
   if (convertView == null) {
    convertView = LayoutInflater.from(context).inflate(R.layout.pomenu_item, null);
    holder = new ViewHolder();
    convertView.setTag(holder);
    holder.groupItem = (TextView) convertView.findViewById(R.id.textView);
   } else {
    holder = (ViewHolder) convertView.getTag();
   }
   holder.groupItem.setText(itemList.get(position));
   return convertView;
  }
  private final class ViewHolder {
   TextView groupItem;
  }
 }
}