首先在主介面定義一個點選事件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.xh.tx.popup_window.MainActivity" >

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="62dp"
        android:text="Button" />

</RelativeLayout>
 

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/ic_launcher"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        android:text="彈出窗體" />

</LinearLayout>
 

package com.xh.tx.popup_window;

import android.app.Activity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.PopupWindow;

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		final Button button=(Button) findViewById(R.id.button);
		button.setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				LayoutInflater myInflater=getLayoutInflater();
				View view=myInflater.inflate(R.layout.popup_window, null);
				//窗體的大小一起可以設定
				PopupWindow popup=new PopupWindow(view, 250, 400);
				//設定背景顏色
				popup.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.alert_dark_frame));
				popup.setOutsideTouchable(true);
				//popup.showAsDropDown(button);
				//把窗體顯示出來並且顯示的位置
				popup.showAtLocation(getWindow().getDecorView(), Gravity.CENTER, 0, 0);
				
			}
		});
	}

}