PopupWindow 是一种阻塞式的弹出窗口，这就意味着在我们退出这个弹出框之前，程序会一直等待。它可以浮动在当前Activity的任何的位置上。 需要注意的是，PopupWindow必须触发某个焦点或者某个事件才会显示出来，不然总会会出现错误。

下面是使用PopupWindow 弹出自定义菜单的例子

当我们点击Menu键的时候，会在当前的Activity最下方弹出一个菜单。

效果图如下：

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);

}

/**
* 在此方法中实现自定义菜单栏
*/
public boolean onMenuOpened(int featureId, Menu menu) {
if (pw != null) {
if (pw.isShowing()) {
// 就关闭弹出窗口
pw.dismiss();
}
else {
//在指定位置弹出窗口
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对象
pw = new PopupWindow(view,LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);

//在指定位置弹出窗口
pw.showAtLocation(findViewById(R.id.tv), Gravity.CENTER, 0, 300);

}
// 此处返回false，系统不会执行onCreateOptionsMenu中添加的菜单
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




menu.xml

menu_bg_frame.xml 这个文件是菜单背景的样式文件，在drawable-hdpi文件下面

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