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

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); } } 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