Android高手进阶教程(十)之----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!! 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~