import android.app.Activity;
import android.graphics.drawable.BitmapDrawable;
import android.os.Build;
import android.os.Bundle;
import android.util.DisplayMetrics;
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 ActivityMain extends Activity {

    private int screenWidth;
    private int screenHeigh;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        System.out.println("xirtam " + Build.VERSION.SDK);
        System.out.println("xirtam " + Build.VERSION.SDK_INT);
        {// 获取屏幕宽高
            DisplayMetrics dm = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(dm);
            screenWidth = dm.widthPixels;
            screenHeigh = dm.heightPixels;
        }

        LayoutInflater inflater = LayoutInflater.from(this);
        // 引入窗口配置文件
        View view = inflater.inflate(R.layout.main2, null);
        // 创建PopupWindow对象
        final PopupWindow pop = new PopupWindow(view,
                LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT, false);
        Button btn = (Button) findViewById(R.id.btn);
        // 需要设置一下此参数，点击外边可消失
        pop.setBackgroundDrawable(new BitmapDrawable());
        // 设置点击窗口外边窗口消失
        pop.setOutsideTouchable(true);
        // 设置此参数获得焦点，否则无法点击
        pop.setFocusable(true);
        btn.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (pop.isShowing()) {
                    // 隐藏窗口，如果设置了点击窗口外小时即不需要此方式隐藏
                    pop.dismiss();
                } else {
                    // 显示窗口
                    pop.setAnimationStyle(R.style.PopupAnimation);
                    pop.showAtLocation(v, Gravity.NO_GRAVITY, 0, screenHeigh);
//                    pop.showAsDropDown(v);
                    pop.update();
                }

            }
        });
    }

}

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

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="点我是小狗" />

</LinearLayout>

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

    <Button
        android:id="@+id/a"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:text="小狗你好" />

</LinearLayout>

<style name="PopupAnimation" mce_bogus="1" parent="android:Animation">
        <item name="android:windowEnterAnimation">@anim/enter</item>
        <item name="android:windowExitAnimation">@anim/exit</item>
    </style>

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="3500"
    android:fromYDelta="100%"
    android:toYDelta="1%" >

</translate>

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="3500"
    android:fromYDelta="1%"
    android:toYDelta="100%" >

</translate>