Android 自定义PopupWindow动画效果

public class RollActivity extends Activity {
    private View view;
    private Button btn;
    private PopupWindow mPopupWindow;
    private View[] btns;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
//        LinearLayout layout=(LinearLayout) view.findViewById(R.id.layout_main);
//        //设置背景图片旋转180
//        Bitmap mBitmap=setRotate(R.drawable.bg_kuang);
//        BitmapDrawable drawable=new BitmapDrawable(mBitmap);
//        layout.setBackgroundDrawable(drawable);
        
        btn=(Button) this.findViewById(R.id.btn);
        btn.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                showPopupWindow(btn);
            }
            
        });
        
        initPopupWindow(R.layout.popwindow);

    }
    
    private void initPopupWindow(int resId){
        LayoutInflater mLayoutInflater = (LayoutInflater)getSystemService(LAYOUT_INFLATER_SERVICE);
        view = mLayoutInflater.inflate(resId, null);
            
        mPopupWindow = new PopupWindow(view, 400,LayoutParams.WRAP_CONTENT);
//        mPopupWindow.setBackgroundDrawable(new BitmapDrawable());//必须设置background才能消失
        mPopupWindow.setBackgroundDrawable(getResources().getDrawable(R.drawable.bg_frame));
        mPopupWindow.setOutsideTouchable(true);
        
        //自定义动画
//        mPopupWindow.setAnimationStyle(R.style.PopupAnimation);
        //使用系统动画
        mPopupWindow.setAnimationStyle(android.R.style.Animation_Dialog);
        mPopupWindow.update();
        mPopupWindow.setTouchable(true);
        mPopupWindow.setFocusable(true);
        
        btns=new View[3];
        btns[0]=view.findViewById(R.id.btn_0);
        btns[1]=view.findViewById(R.id.btn_1);
        btns[2]=view.findViewById(R.id.btn_2);
        btns[0].setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                //doSomething
            }
        });
        btns[1].setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                //doSomething
            }
        });
        btns[2].setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                //doSomething
            }
        });
    }
    private void showPopupWindow(View view) {
        if(!mPopupWindow.isShowing()){
//            mPopupWindow.showAsDropDown(view,0,0);
            mPopupWindow.showAtLocation(view, Gravity.CENTER, 0, 0);
        }
    }
    public Bitmap setRotate(int resId) {
        Matrix mFgMatrix = new Matrix();
        Bitmap mFgBitmap = BitmapFactory.decodeResource(getResources(), resId);
        mFgMatrix.setRotate(180f);
        return mFgBitmap=Bitmap.createBitmap(mFgBitmap, 0, 0, 
                mFgBitmap.getWidth(), mFgBitmap.getHeight(), mFgMatrix, true);
    }
}

<?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="wrap_content"   
        android:orientation="horizontal"  
        android:id="@+id/layout_main"  
        >  
        <LinearLayout android:layout_width="fill_parent"  
            android:layout_height="wrap_content"  
            android:orientation="vertical"  
            android:gravity="center_horizontal"  
            android:clickable="true"  
            android:background="@drawable/state_btn_pressed"  
            android:layout_weight="1"  
            android:id="@+id/btn_0"  
            >  
            <ImageView android:layout_width="wrap_content"  
                android:layout_height="wrap_content"   
                android:scaleType="fitCenter"  
                android:src="@drawable/ic_call"  
                >  
            </ImageView>  
            <TextView android:layout_width="wrap_content"  
                android:layout_height="wrap_content"   
                android:textColor="#000000"  
                android:textSize="18px"  
                android:text="电话">  
            </TextView>  
        </LinearLayout>  
        <LinearLayout android:layout_width="fill_parent"  
            android:layout_height="wrap_content"  
            android:orientation="vertical"  
            android:gravity="center_horizontal"  
            android:clickable="true"  
            android:background="@drawable/state_btn_pressed"  
            android:layout_weight="1"  
            android:id="@+id/btn_1"  
            >  
            <ImageView android:layout_width="wrap_content"  
                android:layout_height="wrap_content"   
                android:scaleType="fitCenter"  
                android:src="@drawable/ic_home"  
                >  
            </ImageView>  
            <TextView android:layout_width="wrap_content"  
                android:layout_height="wrap_content"   
                android:textColor="#000"  
                android:textSize="18px"  
                android:text="空间">  
            </TextView>  
        </LinearLayout>  
          
        <LinearLayout android:layout_width="fill_parent"  
            android:layout_height="wrap_content"  
            android:orientation="vertical"  
            android:gravity="center_horizontal"  
            android:clickable="true"  
            android:background="@drawable/state_btn_pressed"  
            android:layout_weight="1"  
            android:id="@+id/btn_2"  
            >  
            <ImageView android:layout_width="wrap_content"  
                android:layout_height="wrap_content"   
                android:scaleType="fitCenter"  
                android:src="@drawable/ic_sms"  
                >  
            </ImageView>  
            <TextView android:layout_width="wrap_content"  
                android:layout_height="wrap_content"   
                android:textColor="#000"  
                android:textSize="18px"  
                android:text="短信"  
                >  
            </TextView>  
        </LinearLayout>  
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>  
<selector xmlns:android="http://schemas.android.com/apk/res/android">  
    <item android:state_pressed="true"  
        android:drawable="@drawable/bg_btn_pressed"  
        android:padding="0dp"/>  
</selector>  

<?xml version="1.0" encoding="utf-8"?>  
<set xmlns:android="http://schemas.android.com/apk/res/android">  
    <scale android:fromXScale="0.6" android:toXScale="1.1"  
        android:fromYScale="0.6" android:toYScale="1.1" android:pivotX="50%"  
        android:pivotY="50%" android:duration="200" />  
    <scale android:fromXScale="1.0" android:toXScale="0.91"  
        android:fromYScale="1.0" android:toYScale="0.91" android:pivotX="50%"  
        android:pivotY="50%" android:duration="400" android:delay="200" />  
    <alpha android:interpolator="@android:anim/linear_interpolator"  
        android:fromAlpha="0.0" android:toAlpha="1.0" android:duration="400" />  
</set>  

<?xml version="1.0" encoding="utf-8"?>  
<set xmlns:android="http://schemas.android.com/apk/res/android">  
    <scale android:fromXScale="1.0" android:toXScale="1.25"  
        android:fromYScale="1.0" android:toYScale="1.25" android:pivotX="50%"  
        android:pivotY="50%" android:duration="200" />  
    <scale android:fromXScale="1.0" android:toXScale="0.48"  
        android:fromYScale="1.0" android:toYScale="0.48" android:pivotX="50%"  
        android:pivotY="50%" android:duration="400" android:delay="200" />  
    <alpha android:interpolator="@android:anim/linear_interpolator"  
        android:fromAlpha="1.0" android:toAlpha="0.0" android:duration="400" />  
</set>  

<?xml version="1.0" encoding="utf-8"?>  
<resources>  
    <style name="PopupAnimation" parent="android:Animation"  
        mce_bogus="1">  
        <item name="android:windowEnterAnimation">@anim/anim_dialog_show</item>  
        <item name="android:windowExitAnimation">@anim/anim_dialog_hide</item>  
    </style>  
</resources>