android弹出窗口的实现（PopupWindow）

           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" >

    <TextView
        android: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" />

    <Button
        android: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" />

    <Button
        android: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" >

    <include
        android:id="@+id/top_title"
        layout="@layout/title_two_button" />

</LinearLayout>

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"
     >


    <ImageView
        android:id="@+id/iv_group_list_bg_divider"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/group_divider"
         />

    <ListView
        android: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" >

    <TextView
        android: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;

	}

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

	@Override
	public Object getItem(int position) {

		return list.get(position);
	}

	@Override
	public long getItemId(int position) {
		return position;
	}

	@Override
	public 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() {

			@Override
			public 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() {

			@Override
			public 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！