Android实现图片倒影效果

直接上代码

package com.turlet.shadow;

import android.app.Activity;
import android.os.Bundle;

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new ImageShadowView(this));
    }
}

package com.turlet.shadow;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.PorterDuff.Mode;
import android.graphics.PorterDuffXfermode;
import android.graphics.Shader.TileMode;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
/**
 * 
 * @author turlet
 *
 */
public class ImageShadowView extends SurfaceView implements SurfaceHolder.Callback{

    private Bitmap mBitmap;
    
    public ImageShadowView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
        SurfaceHolder holder = this.getHolder();
        holder.addCallback(this);
        mBitmap = BitmapFactory.decodeResource(context.getResources(), R.drawable.xiaochuan);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        super.onDraw(canvas);
        int width = mBitmap.getWidth();
        int height = mBitmap.getHeight();
        canvas.drawBitmap(mBitmap, 0, 0, null);
        
        Bitmap nBitmap = setShadow(mBitmap);
        nBitmap = setAlpha(nBitmap,50);//一半透明
        canvas.drawBitmap(nBitmap, 0, height+2, null);
        
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        // TODO Auto-generated method stub
        Canvas canvas = holder.lockCanvas();
        this.onDraw(canvas);
        holder.unlockCanvasAndPost(canvas);
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
            int height) {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        // TODO Auto-generated method stub
        
    }
    /**
     * 
     * @param sourceImg 传入的图片
     * @param number 0-100(0为完全透明，100为不透明)
     * @return Bitmap 处理后的图片
     */
    public static Bitmap setAlpha(Bitmap sourceImg, int number) {   
         int[] argb = new int[sourceImg.getWidth() * sourceImg.getHeight()];   
         sourceImg.getPixels(argb, 0, sourceImg.getWidth(), 0, 0,sourceImg.getWidth(), sourceImg.getHeight());   
         number = number * 255 / 100;   
         double round = (double)number/(double)(argb.length);
         System.out.println(round+ "  l="+argb.length +" n="+number);
         for (int i = 0; i < argb.length; i++) {   
          if(number-i*round>10){
              argb[i] = ((int)(number-i*round) << 24) | (argb[i] & 0x00FFFFFF);
              continue;
          }
          else{
              argb[i] = (10 << 24) | (argb[i] & 0x00FFFFFF);
              continue;
          }

         }   
         sourceImg = Bitmap.createBitmap(argb, sourceImg.getWidth(), sourceImg.getHeight(), Config.ARGB_8888);   
            
         return sourceImg;   
       }   
    /**
     * 传入一张图片，经倒转后，再取一半
     * @param bitmap
     * @return
     */
    public static Bitmap setShadow(Bitmap bitmap){
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        Matrix matrix = new Matrix();
        matrix.preScale(1, -1);
        Bitmap shadowImage = Bitmap.createBitmap(bitmap, 0, height / 2,
                width, height / 2, matrix, false);
        return shadowImage;
    }

}

 效果图: