Android開發教程：Popupwindow的應用

PopupWindow 是一種阻塞式的彈出窗口，這就意味著在我們退出這個彈出框之前，程序會一直等待。它可以浮動在當前Activity的任何的位置上。 需要注意的是，PopupWindow必須觸發某個焦點或者某個事件才會顯示出來，不然總會會出現錯誤。

下面是使用PopupWindow 彈出自定義菜單的例子

當我們點擊Menu鍵的時候，會在當前的Activity最下方彈出一個菜單。

效果圖如下：

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PopupMenuDemo.java

package com.lingdududu.popupWindow;  
 
import Android.app.Activity;  
import android.content.Context;  
import android.graphics.drawable.BitmapDrawable;  
import android.os.Bundle;  
import android.view.Gravity;  
import android.view.KeyEvent;  
import android.view.LayoutInflater;  
import android.view.Menu;  
import android.view.MenuItem;  
import android.view.View;  
import android.view.ViewGroup;  
import android.widget.BaseAdapter;  
import android.widget.GridView;  
import android.widget.ImageView;  
import android.widget.LinearLayout;  
import android.widget.PopupWindow;  
import android.widget.TextView;  
import android.widget.LinearLayout.LayoutParams;  
 
public class PopupMenuDemo extends Activity {  
      
    private int[] resArray = new int[] {  
            R.drawable.icon_menu_addto, R.drawable.icon_menu_audioinfo,  
            R.drawable.icon_menu_findlrc, R.drawable.icon_menu_scan  
    };  
      
    private String[] title = new String[]{  
            "添加", "信息", "搜索", "查看" 
    };  
      
    private PopupWindow pw = null;  
      
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
    }  
      
 
    @Override 
    public boolean onCreateOptionsMenu(Menu menu) {  
        menu.add("");  
        return super.onCreateOptionsMenu(menu);  
          
    }  
      
    /**  
     * 在此方法中實現自定義菜單欄  
     */ 
    public boolean onMenuOpened(int featureId, Menu menu) {  
        if (pw != null) {  
            if (pw.isShowing()) {  
                // 就關閉彈出窗口  
                pw.dismiss();  
            }   
            else {  
                //在指定位置彈出窗口  
                pw.showAtLocation(findViewById(R.id.tv), Gravity.CENTER, 0, 300);  
            }  
        }   
        else {  
 
            LayoutInflater inflater = (LayoutInflater)this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);        
            View view = inflater.inflate(R.layout.menu, null);  
            GridView grid1 = (GridView)view.findViewById(R.id.menuGridChange);  
            grid1.setAdapter(new ImageAdapter(this));  
              
              
            //生成PopupWindow對象  
            pw = new PopupWindow(view,LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);  
              
            //在指定位置彈出窗口  
            pw.showAtLocation(findViewById(R.id.tv), Gravity.CENTER, 0, 300);  
 
        }  
        // 此處返回false，系統不會執行onCreateOptionsMenu中添加的菜單  
        return false;  
    }  
 
 
    public boolean onKeyDown(int keyCode, KeyEvent event) {  
          
        if(keyCode==KeyEvent.KEYCODE_BACK){  
            pw.dismiss();  
            return false;  
        }  
        return super.onKeyDown(keyCode, event);  
    }  
    @Override 
    public boolean onOptionsItemSelected(MenuItem item) {  
        return super.onOptionsItemSelected(item);  
    }  
 
 
    public class ImageAdapter extends BaseAdapter {  
          
        private Context context;  
          
        public ImageAdapter(Context context) {  
            this.context = context;  
        }  
          
        @Override 
        public int getCount() {  
            return resArray.length;  
        }  
 
        @Override 
        public Object getItem(int arg0) {  
            return resArray[arg0];  
        }  
 
        @Override 
        public long getItemId(int arg0) {  
            return arg0;  
        }  
 
        @Override 
        public View getView(int arg0, View arg1, ViewGroup arg2) {  
            LinearLayout linear = new LinearLayout(context);  
            LinearLayout.LayoutParams params = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);  
            linear.setOrientation(LinearLayout.VERTICAL);  
              
            ImageView iv = new ImageView(context);  
            iv.setImageBitmap(((BitmapDrawable)context.getResources().getDrawable(resArray[arg0])).getBitmap());  
            LinearLayout.LayoutParams params2 = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);  
            params2.gravity=Gravity.CENTER;  
            linear.addView(iv, params2);  
              
            TextView tv = new TextView(context);  
            tv.setText(title[arg0]);  
            LinearLayout.LayoutParams params3 = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);  
            params3.gravity=Gravity.CENTER;  
              
            linear.addView(tv, params3);  
              
            return linear;  
        }  
    }  
} 

main.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    > 
<TextView    
    android:id="@+id/tv" 
    android:layout_width="fill_parent"   
    android:layout_height="wrap_content"   
    android:text="@string/hello" 
    /> 
</LinearLayout> 

menu.xml

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    > 
<TextView    
    android:id="@+id/tv" 
    android:layout_width="fill_parent"   
    android:layout_height="wrap_content"   
    android:text="@string/hello" 
    /> 
</LinearLayout> 

menu_bg_frame.xml 這個文件是菜單背景的樣式文件，在drawable-hdpi文件下面

<?xml version="1.0" encoding="UTF-8"?> 
<shape android:shape="rectangle" xmlns:android="http://schemas.android.com/apk/res/android"> 
    <solid android:color="#b4000000" /> 
    <stroke android:width="2.0dip" android:color="#b4ffffff" android:dashWidth="3.0dip" android:dashGap="0.0dip" /> 
    <padding android:left="7.0dip" android:top="7.0dip" android:right="7.0dip" android:bottom="7.0dip" /> 
    <corners android:radius="8.0dip" /> 
</shape>