(十)Android PopupWindow的使用!!!

大家好，我们这一节讲的是Android PopupWindow的使用! 在我理解其实PopupWindow其实类似于一个不能动的Widget(仅从显示效果来说!)   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:         下面是核心代码:   ~~~ 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); } }} ~~~ 需要强调的是这里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 ### [Android高手进阶教程(九)之----Android Handler的使用!!](http://blog.csdn.net/Android_Tutor/archive/2010/05/08/5568806.aspx)看一看，加深了解:   下面是核心代码:   ~~~ 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); }} ~~~   效果如下图:      这样就可以初始化PopupWindow了,呵呵，这一节的布局文件有点多，如果大家想要源码的话，留下你们的Email,我会尽快发送给大家的 ，今天就到这里，大家有什么不明白的欢迎留言!!!谢谢~   要源码的太多，我快崩溃了，所以上传了。下载地址: [http://d.download.csdn.net/down/2871531/Android_Tutor](http://d.download.csdn.net/down/2871531/Android_Tutor)