最近看到新浪微博顶部栏的微博分组效果很炫，从网上查了一些资料明白原来是用PopupWindow实现的，今天自己也写了一个例子实现了这种效果，希望对大家有帮助。

PopupWindow就是弹出窗口的意思，类似windows下面的开始按钮。PopupWindow可以实现浮层效果，而且可以自定义显示位置，出现和退出时的动画.

首先定义新浪微博的顶部栏,title_two_button.xml和main.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="wrap_content" ><TextViewandroid:id="@+id/tvtitle"android:layout_width="fill_parent"android:layout_height="45dip"android:background="@drawable/search_bg"android:gravity="center"android:text="天堂没有路"android:textColor="@color/black"android:textSize="25dip" /><Buttonandroid:id="@+id/btn_title_left"android:layout_width="50dip"android:layout_height="35dip"android:layout_gravity="center_vertical"android:background="@drawable/title_button"android:textColor="@color/white" /><Buttonandroid:id="@+id/btn_title_right"android:layout_width="50dip"android:layout_height="35dip"android:layout_gravity="right"android:layout_marginRight="2dip"android:layout_marginTop="4dip"android:background="@drawable/title_button2"android:textColor="@color/white" /></FrameLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:background="@android:color/white"android:orientation="vertical" ><includeandroid:id="@+id/top_title"layout="@layout/title_two_button" /></LinearLayout>

主要是为了实现一个这样的界面：

接下来定义弹出对话框的布局文件group_list.xml和group_item_view.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="fill_parent"android:background="@drawable/group_bg"android:orientation="vertical"><ImageViewandroid:id="@+id/iv_group_list_bg_divider"android:layout_width="fill_parent"android:layout_height="wrap_content"android:background="@drawable/group_divider"/><ListViewandroid:id="@+id/lvGroup"android:layout_width="fill_parent"android:layout_height="fill_parent"android:divider="@drawable/group_divider"/></LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="fill_parent"android:layout_height="@dimen/group_item_height"android:orientation="vertical" ><TextViewandroid:id="@+id/groupItem"android:textColor="#ffffff"android:textSize="18dp"android:layout_width="fill_parent"android:layout_height="fill_parent"android:gravity="center" /></LinearLayout>

自定义一个适配器：GroupAdapter

import java.util.List;import cn.com.karl.popwindow.R;import android.content.Context;
import android.graphics.Color;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;public class GroupAdapter extends BaseAdapter {private Context context;private List<String> list;public GroupAdapter(Context context, List<String> list) {this.context = context;this.list = list;}@Overridepublic int getCount() {return list.size();}@Overridepublic Object getItem(int position) {return list.get(position);}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup viewGroup) {ViewHolder holder;if (convertView==null) {convertView=LayoutInflater.from(context).inflate(R.layout.group_item_view, null);holder=new ViewHolder();convertView.setTag(holder);holder.groupItem=(TextView) convertView.findViewById(R.id.groupItem);}else{holder=(ViewHolder) convertView.getTag();}holder.groupItem.setTextColor(Color.BLACK);holder.groupItem.setText(list.get(position));return convertView;}static class ViewHolder {TextView groupItem;}}

最后是我要实现弹出对话框的核心类PoupWindowDemoActivity

import java.util.ArrayList;
import java.util.List;import cn.com.karl.adapter.GroupAdapter;import android.app.Activity;
import android.content.Context;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListView;
import android.widget.PopupWindow;
import android.widget.TextView;
import android.widget.Toast;public class PoupWindowDemoActivity extends Activity {private PopupWindow popupWindow;private ListView lv_group;private View view;private View top_title;private TextView tvtitle;private List<String> groups;public void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);this.requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.main);top_title = this.findViewById(R.id.top_title);tvtitle = (TextView) top_title.findViewById(R.id.tvtitle);tvtitle.setText("天堂没有路");tvtitle.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {showWindow(v);}});}private void showWindow(View parent) {if (popupWindow == null) {LayoutInflater layoutInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);view = layoutInflater.inflate(R.layout.group_list, null);lv_group = (ListView) view.findViewById(R.id.lvGroup);// 加载数据groups = new ArrayList<String>();groups.add("全部");groups.add("我的微博");groups.add("好友");groups.add("亲人");groups.add("同学");groups.add("朋友");groups.add("陌生人");GroupAdapter groupAdapter = new GroupAdapter(this, groups);lv_group.setAdapter(groupAdapter);// 创建一个PopuWidow对象popupWindow = new PopupWindow(view, 300, 350);}// 使其聚集popupWindow.setFocusable(true);// 设置允许在外点击消失popupWindow.setOutsideTouchable(true);// 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popupWindow.setBackgroundDrawable(new BitmapDrawable());WindowManager windowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);// 显示的位置为:屏幕的宽度的一半-PopupWindow的高度的一半int xPos = windowManager.getDefaultDisplay().getWidth() / 2- popupWindow.getWidth() / 2;Log.i("coder", "xPos:" + xPos);popupWindow.showAsDropDown(parent, xPos, 0);lv_group.setOnItemClickListener(new OnItemClickListener() {@Overridepublic void onItemClick(AdapterView<?> adapterView, View view,int position, long id) {Toast.makeText(PoupWindowDemoActivity.this,groups.get(position), 1000).show();if (popupWindow != null) {popupWindow.dismiss();}}});}
}

这样就完成了一个弹出对话框的效果，下面来看一下吧！

再看一张新浪微博的弹出对话框效果：

已经完成，我们可以把这项功能加入自己的做的新浪微博里，为自己的应用增添点特色色彩吧！