第二步:新建一个.java文件,命名为ImageUtil.java,在里面定义一些图片处理方法,代码如下:

package com.android.tutor;  
import android.graphics.Bitmap;  
import android.graphics.Canvas;  
import android.graphics.LinearGradient;  
import android.graphics.Matrix;  
import android.graphics.Paint;  
import android.graphics.PixelFormat;  
import android.graphics.PorterDuffXfermode;  
import android.graphics.Rect;  
import android.graphics.RectF;  
import android.graphics.Bitmap.Config;  
import android.graphics.PorterDuff.Mode;  
import android.graphics.Shader.TileMode;  
import android.graphics.drawable.Drawable;  
public class ImageUtil {  
      
    //放大缩小图片   
    public static Bitmap zoomBitmap(Bitmap bitmap,int w,int h){  
        int width = bitmap.getWidth();  
        int height = bitmap.getHeight();  
        Matrix matrix = new Matrix();  
        float scaleWidht = ((float)w / width);  
        float scaleHeight = ((float)h / height);  
        matrix.postScale(scaleWidht, scaleHeight);  
        Bitmap newbmp = Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);  
        return newbmp;  
    }  
    //将Drawable转化为Bitmap   
     public static Bitmap drawableToBitmap(Drawable drawable){  
            int width = drawable.getIntrinsicWidth();  
            int height = drawable.getIntrinsicHeight();  
            Bitmap bitmap = Bitmap.createBitmap(width, height,  
                    drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888  
                            : Bitmap.Config.RGB_565);  
            Canvas canvas = new Canvas(bitmap);  
            drawable.setBounds(0,0,width,height);  
            drawable.draw(canvas);  
            return bitmap;  
              
        }  
       
     //获得圆角图片的方法   
    public static Bitmap getRoundedCornerBitmap(Bitmap bitmap,float roundPx){  
          
        Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap  
                .getHeight(), Config.ARGB_8888);  
        Canvas canvas = new Canvas(output);  
   
        final int color = 0xff424242;  
        final Paint paint = new Paint();  
        final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());  
        final RectF rectF = new RectF(rect);  
   
        paint.setAntiAlias(true);  
        canvas.drawARGB(0, 0, 0, 0);  
        paint.setColor(color);  
        canvas.drawRoundRect(rectF, roundPx, roundPx, paint);  
   
        paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));  
        canvas.drawBitmap(bitmap, rect, rect, paint);  
   
        return output;  
    }  
    //获得带倒影的图片方法   
    public static Bitmap createReflectionImageWithOrigin(Bitmap bitmap){  
        final int reflectionGap = 4;  
        int width = bitmap.getWidth();  
        int height = bitmap.getHeight();  
          
        Matrix matrix = new Matrix();  
        matrix.preScale(1, -1);  
          
        Bitmap reflectionImage = Bitmap.createBitmap(bitmap,   
                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(bitmap, 0, 0, null);  
        Paint deafalutPaint = new Paint();  
        canvas.drawRect(0, height,width,height + reflectionGap,  
                deafalutPaint);  
          
        canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);  
          
        Paint paint = new Paint();  
        LinearGradient shader = new LinearGradient(0,  
                bitmap.getHeight(), 0, bitmapWithReflection.getHeight()  
                + reflectionGap, 0x70ffffff, 0x00ffffff, TileMode.CLAMP);  
        paint.setShader(shader);  
        // Set the Transfer mode to be porter duff and destination in   
        paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));  
        // Draw a rectangle using the paint with our linear gradient   
        canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()  
                + reflectionGap, paint);  
   
        return bitmapWithReflection;  
    }  
      
}  

package com.android.tutor;  
import android.app.Activity;  
import android.graphics.Bitmap;  
import android.graphics.drawable.Drawable;  
import android.os.Bundle;  
import android.widget.ImageView;  
public class Imagedemo extends Activity {  
    private ImageView mImageView01,mImageView02;  
      
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
        setupViews();  
    }  
     
    private void setupViews(){  
        mImageView01 = (ImageView)findViewById(R.id.image01);  
        mImageView02 = (ImageView)findViewById(R.id.image02);  
          
        //获取壁纸返回值是Drawable   
        Drawable drawable = getWallpaper();  
        //将Drawable转化为Bitmap   
        Bitmap bitmap = ImageUtil.drawableToBitmap(drawable);  
        //缩放图片   
        Bitmap zoomBitmap = ImageUtil.zoomBitmap(bitmap, 100, 100);  
        //获取圆角图片   
        Bitmap roundBitmap = ImageUtil.getRoundedCornerBitmap(zoomBitmap, 10.0f);  
        //获取倒影图片   
        Bitmap reflectBitmap = ImageUtil.createReflectionImageWithOrigin(zoomBitmap);  
        //这里可以让Bitmap再转化为Drawable   
//      Drawable roundDrawable = new BitmapDrawable(roundBitmap);          
//      Drawable reflectDrawable = new BitmapDrawable(reflectBitmap);          
//      mImageView01.setBackgroundDrawable(roundDrawable);   
//      mImageView02.setBackgroundDrawable(reflectDrawable);   
                  
        mImageView01.setImageBitmap(roundBitmap);  
        mImageView02.setImageBitmap(reflectBitmap);  
    }  
        
         
}

第五步:运行上述工程,查看效果如下: