如何实现倒影效果

package com.easymorse.picture;


import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;
import android.graphics.Shader.TileMode;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.widget.ImageView;


public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ImageView imageView2 = (ImageView) findViewById(R.id.picture_qian);


Bitmap bmp = ((BitmapDrawable) getResources().getDrawable(
R.drawable.qian)).getBitmap();


imageView2.setImageBitmap(createReflectedImage(bmp));
}


public static Bitmap createReflectedImage(Bitmap originalImage) {


final int reflectionGap = 4;


int width = originalImage.getWidth();
int height = originalImage.getHeight();


Matrix matrix = new Matrix();
matrix.preScale(1, -1);


Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,
height / 2, width, height / 2, matrix, false);


Bitmap bitmapWithReflection = Bitmap.createBitmap(width,
(height + height / 2), Config.ARGB_8888);


Canvas canvas = new Canvas(bitmapWithReflection);


canvas.drawBitmap(originalImage, 0, 0, null);


Paint defaultPaint = new Paint();
canvas.drawRect(0, height, width, height + reflectionGap, defaultPaint);


canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);


Paint paint = new Paint();
LinearGradient shader = new LinearGradient(0,
originalImage.getHeight(), 0, bitmapWithReflection.getHeight()
+ reflectionGap, 0x70ffffff, 0x00ffffff,
TileMode.MIRROR);


paint.setShader(shader);


paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));


canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()
+ reflectionGap, paint);


return bitmapWithReflection;
}

}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
    <ImageView android:id="@+id/picture_qian"


android:layout_width="fill_parent" android:layout_height="fill_parent"
android:src="@drawable/qian" />
</LinearLayout>