Android的PopupWindow彈出效果

MainActivity如下:

package com.cn.testpopupwindow;
import android.app.Activity;
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.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.PopupWindow;
public class MainActivity extends Activity {
    private Button button;
    private Button button1;
    private Button button2;
    private Button button3;
    private Button button4;
    private View popupWindowView;
    private PopupWindow popupWindow;
    private LayoutInflater inflater;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        button=(Button) findViewById(R.id.button);
        button.setOnClickListener(new ButtonOnClickListener());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    private class ButtonOnClickListener implements OnClickListener{
        public void onClick(View v) {
            inflater=(LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
            popupWindowView=inflater.inflate(R.layout.popupwindow, null);

            popupWindow=new PopupWindow(popupWindowView, LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT,true);
            //必須要有這句否則彈出popupWindow后監聽不到Back鍵
            popupWindow.setBackgroundDrawable(new BitmapDrawable());
            popupWindow.showAtLocation(findViewById(R.id.button), Gravity.NO_GRAVITY, 0, 0);
            //讓popupWindow獲得焦點
            popupWindow.setFocusable(true);
            //設置動畫
            popupWindow.setAnimationStyle(R.style.popupWindowAnimation);
            popupWindow.update();

            //popupWindow中按鈕的處理
            button1=(Button) popupWindowView.findViewById(R.id.button1);
            button2=(Button) popupWindowView.findViewById(R.id.button2);
            button3=(Button) popupWindowView.findViewById(R.id.button3);
            button4=(Button) popupWindowView.findViewById(R.id.button4);
            button1.setOnClickListener(new ButtonsOnClickListener());
            button2.setOnClickListener(new ButtonsOnClickListener());
            button3.setOnClickListener(new ButtonsOnClickListener());
            button4.setOnClickListener(new ButtonsOnClickListener());

        }

    }

    private class ButtonsOnClickListener implements OnClickListener {
        public void onClick(View v) {
            switch (v.getId()) {
            case R.id.button1:
                System.out.println("點擊了按鈕1");
                break;
            case R.id.button2:
                 System.out.println("點擊了按鈕2");
                break;
            case R.id.button3:
                 System.out.println("點擊了按鈕3");
                break;
            case R.id.button4:
                 System.out.println("點擊了按鈕4");
                break;

            default:
                break;
            }

        }

    }

    //監聽Back事件
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode==KeyEvent.KEYCODE_BACK) {
            if (popupWindow!=null&&popupWindow.isShowing()) {
                popupWindow.dismiss();      
            } else {
                MainActivity.this.finish();
            }
        }
        return super.onKeyDown(keyCode, event);
    }
}

Main.xml如下:

<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" >

    <Button 
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="test"
        android:layout_centerInParent="true"
    />

</RelativeLayout>

popupwindow.xml如下:

<?xml version="1.0" encoding="utf-8"?>
<!--注意:在RelativeLayout里面是LinearLayout,且是vertical的-->
<!--第一個Button的 layout_marginTop是相對于父控件而言的-->
<!--但是第二個Button的layout_marginTop是相對于第一個Button而言的  -->
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#f0838b8b"
    android:orientation="vertical"
    >

    <LinearLayout
        android:id="@+id/linerLayout"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:orientation="vertical"
    >

        <Button 
            android:id="@+id/button1"
            android:layout_width="200dip"
            android:layout_height="wrap_content"
            android:text="Button1"
            android:textSize="20sp"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="20dip"
        />
         <Button 
            android:id="@+id/button2"
            android:layout_width="200dip"
            android:layout_height="wrap_content"
            android:text="Button2"
            android:textSize="20sp"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="20dip"
        />
          <Button 
            android:id="@+id/button3"
            android:layout_width="200dip"
            android:layout_height="wrap_content"
            android:text="Button3"
            android:textSize="20sp"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="20dip"
        />
           <Button 
            android:id="@+id/button4"
            android:layout_width="200dip"
            android:layout_height="wrap_content"
            android:text="Button4"
            android:textSize="20sp"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="20dip"
        />


    </LinearLayout>


</RelativeLayout>

style.xml如下

<resources xmlns:android="http://schemas.android.com/apk/res/android">
   <style name="AppTheme" parent="android:Theme.Light" />
   <style name="popupWindowAnimation" mce_bogus="1" parent="android:Animation">
        <item name="android:windowEnterAnimation">@anim/enter</item>
        <item name="android:windowExitAnimation">@anim/exit</item>
    </style>
</resources>

enter.xml動畫如下:

<?xml version="1.0" encoding="utf-8"?>
<!-- android:fromYDelta:動畫開始的點離當前View X坐標上的差值 -->
<!-- 利用100%p表示該動畫在當前View的最下方 -->
<set 
    xmlns:android="http://schemas.android.com/apk/res/android">
    <translate
        android:duration="1500"
        android:fromYDelta="100%p"
        android:interpolator="@android:anim/decelerate_interpolator"
        android:toYDelta="0" />

</set>

exit.xml動畫如下:

<?xml version="1.0" encoding="utf-8"?>
<!-- Alpha=1.0表示不透明,Alpha=0.0表示透明 -->
<set 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:interpolator="@android:anim/decelerate_interpolator" >
    <alpha
        android:duration="1000"
        android:fromAlpha="1.0"
        android:toAlpha="0.0"
     />
</set>