ImageAdapter.java

package com.xiawenquan;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
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.Shader.TileMode;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;

public class ImageAdapter extends BaseAdapter {

	int mGalleryItemBackground;   
    private Context mContext;   
    private Integer[] mImageIds;   
    private ImageView[] mImages;   
       
    public ImageAdapter(Context c, Integer[] ImageIds) {   
     mContext = c;   
     mImageIds = ImageIds;   
     mImages = new ImageView[mImageIds.length];   
    }   
    /**  
     * ������ӰЧ��  
     * @return  
     */  
    public boolean createReflectedImages() {   
     //��Ӱͼ��ԭͼ֮��ľ���   
     final int reflectionGap = 4;   
     int index = 0;   
     for (int imageId : mImageIds) {   
      //����ԭͼ����֮���bitmap����   
      Bitmap originalImage = BitmapFactory.decodeResource(mContext.getResources(), imageId);   
      int width = originalImage.getWidth();   
      int height = originalImage.getHeight();   
      //�����������   
      Matrix matrix = new Matrix();   
         
      //ָ��һ���Ƕ���0,0Ϊ���������ת   
      // matrix.setRotate(30);   
         
      //ָ������(x�᲻�䣬y���෴)   
      matrix.preScale(1, -1);   
         
      //������Ӧ�õ���ԭͼ֮�У�����һ����Ȳ��䣬�߶�Ϊԭͼ1/2�ĵ�Ӱλͼ   
      Bitmap reflectionImage = Bitmap.createBitmap(originalImage, 0,   
        height/2, width, height/2, matrix, false);   
         
      //����һ����Ȳ��䣬�߶�Ϊԭͼ+��Ӱͼ�߶ȵ�λͼ   
      Bitmap bitmapWithReflection = Bitmap.createBitmap(width,   
        (height + height / 2), Config.ARGB_8888);   
         
      //�����洴����λͼ��ʼ��������   
      Canvas canvas = new Canvas(bitmapWithReflection);   
      canvas.drawBitmap(originalImage, 0, 0, null);   
         
      Paint deafaultPaint = new Paint();    
      deafaultPaint.setAntiAlias(false);   
//    canvas.drawRect(0, height, width, height + reflectionGap,deafaultPaint);   
      canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);   
      Paint paint = new Paint();   
      paint.setAntiAlias(false);   
          
      /**  
       * ����һ:Ϊ�������������xλ�ã�  
       * ������:Ϊy��λ�ã�  
       * ����������:�ֱ��Ӧ�����յ㣬  
       * ������Ϊƽ�̷�ʽ��  
       * ��������Ϊ����Gradient�ǻ���Shader�࣬��������ͨ��Paint��setShader�����������������  
       */  
      LinearGradient shader = new LinearGradient(0,originalImage.getHeight(), 0,   
              bitmapWithReflection.getHeight() + reflectionGap,0x70ffffff, 0x00ffffff, TileMode.MIRROR);   
      //������Ӱ   
      paint.setShader(shader);   
      paint.setXfermode(new PorterDuffXfermode(android.graphics.PorterDuff.Mode.DST_IN));   
      //���Ѿ�����õĻ��ʹ���һ��������Ӱ����Ч��   
      canvas.drawRect(0, height, width, bitmapWithReflection.getHeight()+ reflectionGap, paint);   
         
      //����һ��ImageView������ʾ�Ѿ����õ�bitmapWithReflection   
      ImageView imageView = new ImageView(mContext);   
      imageView.setImageBitmap(bitmapWithReflection);   
      //����imageView��С ��Ҳ����������ʾ��ͼƬ��С   
      imageView.setLayoutParams(new GalleryFlow.LayoutParams(220, 400));   
//      imageView.setScaleType(ScaleType.MATRIX);   
      mImages[index++] = imageView;   
     }   
     return true;   
    }   
    @SuppressWarnings("unused")   
    private Resources getResources() {   
        return null;   
    }   
    public int getCount() {   
        return mImageIds.length;   
    }   
    public Object getItem(int position) {   
        return position;   
    }   
    public long getItemId(int position) {   
        return position;   
    }   
    public View getView(int position, View convertView, ViewGroup parent) {   
        return mImages[position];   
    }   
    public float getScale(boolean focused, int offset) {   
        return Math.max(0, 1.0f / (float) Math.pow(2, Math.abs(offset)));   
    }   
}