android PopupWindow

public class MainActivity extends Activity {
    //声明PopupWindow对象
    PopupWindow popupWindow;
    View parent;
    private int[] images = {R.drawable.i1,R.drawable.i2,R.drawable.i3,R.drawable.i4,
            R.drawable.i5,R.drawable.i6,R.drawable.i7,R.drawable.i8};
    private String[] names = {"搜索", "文件管理", "下载管理", "全屏", "网址", "书签", "加入书签", "分享页面"};
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        //通过系统的布局填充器，根据布局文件生成一个view对象
        View contentView = getLayoutInflater().inflate(R.layout.popwindow, null);
        //获取GridView对象
        GridView gridView = (GridView) contentView.findViewById(R.id.gridView);
        //为GridView设置适配器
        gridView.setAdapter(getAdapter());
        //为GridView中的条目设置点击事件
        gridView.setOnItemClickListener(new ItemClickListener());
        //实例化PopupWindow对象
        popupWindow = new PopupWindow(contentView, ViewGroup.LayoutParams.MATCH_PARENT,
                ViewGroup.LayoutParams.WRAP_CONTENT);
        //设置打开PopupWindow时，PopupWindow获取焦点
        popupWindow.setFocusable(true);//取得焦点
        //设置PopupWindow在点击别的组件时自动关闭
        popupWindow.setBackgroundDrawable(new BitmapDrawable());
        //通过样式为PopupWindow设置出现和离开的动画
        popupWindow.setAnimationStyle(R.style.animation);
        
        parent = this.findViewById(R.id.main);
    }
    
    private final class ItemClickListener implements OnItemClickListener{
        //设置点击PopupWindow条目时，PopupWindow自动关闭
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            if(popupWindow.isShowing()) popupWindow.dismiss();//关闭
            //....
        }        
    }
    
    private ListAdapter getAdapter() {
        List<HashMap<String, Object>> data = new ArrayList<HashMap<String,Object>>();
        for(int i = 0 ; i < images.length ; i++ ){
            HashMap<String, Object> item = new HashMap<String, Object>();
            item.put("image", images[i]);
            item.put("name", names[i]);
            data.add(item);
        }
        SimpleAdapter simpleAdapter = new SimpleAdapter(this, data, R.layout.grid_item,
                new String[]{"image", "name"}, new int[]{R.id.imageView, R.id.textView});
        return simpleAdapter;
    }

    public void openPopWindow(View v){
        //设置PopupWindow的出场位置
        popupWindow.showAtLocation(parent, Gravity.BOTTOM, 0, 0);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<resources>
   <!--配置动画的样式文件-->
    <style name="animation">
        <item name="android:windowEnterAnimation">@anim/enter</item> 
        <item name="android:windowExitAnimation">@anim/out</item> 
    </style>
    
</resources>

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:shareInterpolator="false">
    <!--进入动画-->
     <translate
        android:fromYDelta="100%p"
        android:toYDelta="0" 
        android:duration="500"
        />
     <alpha
        android:fromAlpha="0.7"
        android:toAlpha="1.0" 
        android:duration="300"
        />     
</set>

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:shareInterpolator="false">
    <!--离开的动画-->
     <translate
        android:fromYDelta="0"
        android:toYDelta="100%p" 
        android:duration="3000"
        />
     <alpha
        android:fromAlpha="1.0"
        android:toAlpha="0.5" 
        android:duration="2000"
        />     
</set>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" 
    android:background="@drawable/bg"
    >
    <!--PopupWindow网格布局界面，类似于ListView，需要配合条目界面使用-->

    <GridView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:numColumns="4"
        android:horizontalSpacing="10dp"
        android:verticalSpacing="10dp"
        android:id="@+id/gridView"
        />

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" 
    android:gravity="center"
    >
    <!--条目界面-->
    <ImageView 
         android:layout_width="wrap_content"
            android:layout_height="wrap_content"
         android:id="@+id/imageView"
        />
    <TextView 
        android:layout_width="fill_parent"
           android:layout_height="wrap_content"
           android:gravity="center"
           android:textSize="16sp"
           android:textColor="#000099"
        android:id="@+id/textView"
        />
</LinearLayout>