单击按钮下拉菜单

 package com.test.ui;

 import android.app.Activity;
 import android.graphics.drawable.BitmapDrawable;
 import android.os.Bundle;
 import android.view.Gravity;
 import android.view.KeyEvent;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.ViewGroup.LayoutParams;
 import android.widget.Button;
 import android.widget.PopupWindow;
 import android.widget.Toast;

 public class TestActivity extends Activity {
     private Button but_menu;
     private Button open_id;
     private Button save_id;
     View contentView;
     private PopupWindow m_popupWindow;

     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         init();
         setListener();

     }

     private void init() {
         contentView = getLayoutInflater().inflate(R.layout.popupmenu, null,
                 true);
         but_menu = (Button) findViewById(R.id.but_menu);
         open_id = (Button) contentView.findViewById(R.id.btn_popup_information);
         save_id = (Button) contentView.findViewById(R.id.btn_popup_quote);
         // PopupWindow弹出的窗口显示的view,第二和第三参数：分别表示此弹出窗口的大小
         m_popupWindow = new PopupWindow(contentView, LayoutParams.FILL_PARENT,
                 LayoutParams.WRAP_CONTENT, true);

         m_popupWindow.setBackgroundDrawable(new BitmapDrawable());// 有了这句才可以点击返回（撤销）按钮dismiss()popwindow
         m_popupWindow.setOutsideTouchable(true);
         m_popupWindow.setAnimationStyle(R.style.PopupAnimation);
     }

     private void setListener() {
         contentView.setOnClickListener(new View.OnClickListener() {
             public void onClick(View v) {
                 m_popupWindow.dismiss();
             }
         });
         // m_popupWindow = new PopupWindow();
         but_menu.setOnClickListener(new OnClickListener() {
             public void onClick(View v) {
                 try {
                     if (m_popupWindow.isShowing()) {

                         m_popupWindow.dismiss();
                     }
                     m_popupWindow.showAsDropDown(v);

                 } catch (Exception e) {
                     Toast.makeText(TestActivity.this, e.getMessage(),
                             Toast.LENGTH_SHORT);
                 }
             }
         });
         open_id.setOnClickListener(new OnClickListener() {
             public void onClick(View v) {
                 m_popupWindow.dismiss();
                 Toast.makeText(TestActivity.this, "打开被触发", Toast.LENGTH_SHORT)
                         .show();
             }

         });
         save_id.setOnClickListener(new OnClickListener() {
             public void onClick(View v) {
                 m_popupWindow.dismiss();
                 Toast.makeText(TestActivity.this, "保存被触发", Toast.LENGTH_SHORT)
                         .show();
             }

         });
     }

     public boolean onKeyDown(int keyCode, KeyEvent event) {
         if (keyCode == KeyEvent.KEYCODE_BACK) {
             if (m_popupWindow != null && m_popupWindow.isShowing()) {
                 m_popupWindow.dismiss();
                 return true;
             }
         }
         return super.onKeyDown(keyCode, event);
     }
 }

 popupmenu.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/lin_main"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:paddingRight="120dip" >

     <LinearLayout
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:background="@drawable/popup_search"
         android:orientation="vertical" >

         <Button
             android:id="@+id/btn_popup_information"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:layout_weight="1"
             android:background="@drawable/goods_bg"
             android:text="打开"
             android:textColor="#000000"
             android:textSize="16sp" />

         <Button
             android:id="@+id/btn_popup_quote"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:layout_marginTop="5dip"
             android:layout_weight="1"
             android:background="@drawable/goods_bg"
             android:text="保存"
             android:textColor="#000000"
             android:textSize="16sp" />

         <Button
             android:id="@+id/btn_popup_product"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:layout_marginTop="5dip"
             android:layout_weight="1"
             android:background="@drawable/goods_bg"
             android:text="关于我们"
             android:textColor="#000000"
             android:textSize="16sp" />

         <Button
             android:id="@+id/btn_popup_buy"
             android:layout_width="fill_parent"
             android:layout_height="wrap_content"
             android:layout_marginTop="5dip"
             android:layout_weight="1"
             android:background="@drawable/shop_bg"
             android:text="关闭"
             android:textColor="#000000"
             android:textSize="16sp" />
     </LinearLayout>

 </LinearLayout>

 下面的是popwindow出现和退出的动画特效，这种东西网上有很多，就拿出这个吧.
 values/style.xml
 <?xml version="1.0" encoding="utf-8"?>
 <resources>

     <style name="PopupAnimation" parent="android:Animation">
         <item name="android:windowEnterAnimation">@anim/popup_search_show</item>
         <item name="android:windowExitAnimation">@anim/popup_search_hide</item>
     </style>

 </resources>anim/popup_search_show.xml
 <?xml version="1.0" encoding="utf-8"?>
 <set xmlns:android="http://schemas.android.com/apk/res/android" android:interpolator="@android:anim/decelerate_interpolator">

     <scale android:duration="500" android:fromXScale="1.0" android:fromYScale="1.0" android:pivotX="0.100000024%" android:pivotY="0.0" android:toXScale="0.0" android:toYScale="0.0"></scale>

 </set>

 anim/popup_search_hide.xml

 <?xml version="1.0" encoding="utf-8"?>
 <set xmlns:android="http://schemas.android.com/apk/res/android"
     android:interpolator="@android:anim/decelerate_interpolator" >

     <scale
         android:duration="500"
         android:fromXScale="0.0"
         android:fromYScale="0.0"
         android:pivotX="0.100000024%"
         android:pivotY="0.0"
         android:toXScale="1.0"
         android:toYScale="1.0" >
     </scale>

 </set>