Android PopupWindow的使用

它是浮在别的窗口之上的.

下面我将给大家做一个简单的Demo，类似于音乐播放器的Widget的效果，点击Button的时候出来PopupWindow,首先我们看一下效果图:

 package com.android.tutor;
 import android.app.Activity;
 import android.content.Context;
 import android.os.Bundle;
 import android.view.Gravity;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.ViewGroup.LayoutParams;
 import android.widget.Button;
 import android.widget.PopupWindow;
 public class PopupWindowDemo extends Activity  implements OnClickListener{
     private Button btn;

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

         btn = (Button)findViewById(R.id.btn);
         btn.setOnClickListener(this);
     }
     @Override
     public void onClick(View v) {
         Context mContext = PopupWindowDemo.this;
         if (v.getId() == R.id.btn) {
             LayoutInflater mLayoutInflater = (LayoutInflater) mContext
                     .getSystemService(LAYOUT_INFLATER_SERVICE);
             View music_popunwindwow = mLayoutInflater.inflate(
                     R.layout.music_popwindow, null);
             PopupWindow mPopupWindow = new PopupWindow(music_popunwindwow, LayoutParams.FILL_PARENT,
                     LayoutParams.WRAP_CONTENT);

             mPopupWindow.showAtLocation(findViewById(R.id.main), Gravity.RIGHT|Gravity.BOTTOM, 0, 0);
         }
     }
 }

 

要强调的是这里PopupWindow必须有某个事件触发才会显示出来，不然总会抱错，不信大家可以试试!

随着这个问题的出现，就会同学问了，那么我想初始化让PopupWindow显示出来，那怎么办了，不去寄托于其他点击事件，

在这里我用了定时器Timer来实现这样的效果,当然这里就要用到Handler了，如果大家不理解的可以返回

 

 package com.android.tutor;
 import java.util.Timer;
 import java.util.TimerTask;
 import android.app.Activity;
 import android.content.Context;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Message;
 import android.view.Gravity;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup.LayoutParams;
 import android.widget.PopupWindow;
 public class PopupWindowDemo extends Activity{
     private Handler mHandler = new Handler(){

         public void handleMessage(Message msg) {
             switch (msg.what) {
             case 1:
                 showPopupWindow();
                 break;
             }
         };
     };

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

         //create the timer
         Timer timer = new Timer();
         timer.schedule(new initPopupWindow(), 100);
     }

     private class initPopupWindow extends TimerTask{
         @Override
         public void run() {

             Message message = new Message();
             message.what = 1;
             mHandler.sendMessage(message);

         }
     }


     public void showPopupWindow() {
         Context mContext = PopupWindowDemo.this;
         LayoutInflater mLayoutInflater = (LayoutInflater) mContext
                 .getSystemService(LAYOUT_INFLATER_SERVICE);
         View music_popunwindwow = mLayoutInflater.inflate(
                 R.layout.music_popwindow, null);
         PopupWindow mPopupWindow = new PopupWindow(music_popunwindwow,
                 LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
         mPopupWindow.showAtLocation(findViewById(R.id.main), Gravity.CENTER, 0, 0);
     }
 }

 本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/Android_Tutor/archive/2010/05/10/5576533.aspx