android ---- ImageUtil工具類

package com.itcast.util;

import java.io.BufferedInputStream;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileOutputStream;

import java.io.IOException;

import java.net.URL;

import java.net.URLConnection;

import java.security.MessageDigest;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

import android.os.Environment;

import android.os.Handler;

import android.os.Message;

import android.util.Log;
public class ImageUtil {

    private static final String SDCARD_CACHE_IMG_PATH = Environment

            .getExternalStorageDirectory().getPath() + "/itcast/images/";

/** 
 * 保存圖片到SD卡 
 * @param imagePath 
 * @param buffer 
 * @throws IOException 
 */  
public static void saveImage(String imagePath, byte[] buffer)  
        throws IOException {  
    File f = new File(imagePath);  
    if (f.exists()) {  
        return;  
    } else {  
        File parentFile = f.getParentFile();  
        if (!parentFile.exists()) {  
            parentFile.mkdirs();  
        }  
        f.createNewFile();  
        FileOutputStream fos = new FileOutputStream(imagePath);  
        fos.write(buffer);  
        fos.flush();  
        fos.close();  
    }  
}  

/** 
 * 從SD卡加載圖片 
 * @param imagePath 
 * @return 
 */  
public static Bitmap getImageFromLocal(String imagePath){  
    File file = new File(imagePath);  
    if(file.exists()){  
        Bitmap bitmap = BitmapFactory.decodeFile(imagePath);  
        file.setLastModified(System.currentTimeMillis());  
        return bitmap;  
    }  
        return null;  
}  

/** 
 * Bitmap轉換到Byte[] 
 * @param bm 
 * @return 
 */  
public static byte[] bitmap2Bytes(Bitmap bm){     
    ByteArrayOutputStream bas = new ByteArrayOutputStream();       
    bm.compress(Bitmap.CompressFormat.JPEG, 100, bas);       
    return bas.toByteArray();     
   }    

/** 
 * 從本地或者服務端加載圖片 
 * @return 
 * @throws IOException  
 */  
public static Bitmap loadImage(final String imagePath,final String imgUrl,final ImageCallback callback) {  
    Bitmap bitmap = getImageFromLocal(imagePath);  
    if(bitmap != null){  
        return bitmap;  
    }else{//從網上加載  
        final Handler handler = new Handler(){  
            @Override  
            public void handleMessage(Message msg) {  
                if(msg.obj!=null){  
                    Bitmap bitmap = (Bitmap) msg.obj;  
                    callback.loadImage(bitmap, imagePath);  
                }  
            }  
        };  

        Runnable runnable = new Runnable() {  
            @Override  
            public void run() {  
                try {  
                    URL url = new URL(imgUrl);  
                    Log.e("圖片加載", imgUrl);  
                    URLConnection conn = url.openConnection();  
                    conn.connect();  
                    BufferedInputStream bis = new BufferedInputStream(conn.getInputStream(),8192) ;  
                    Bitmap bitmap = BitmapFactory.decodeStream(bis);  
                    //保存文件到sd卡  
                    saveImage(imagePath,bitmap2Bytes(bitmap));  
                    Message msg = handler.obtainMessage();  
                    msg.obj = bitmap;  
                    handler.sendMessage(msg);  
                } catch (IOException e) {  
                    Log.e(ImageUtil.class.getName(), "保存圖片到本地存儲卡出錯！");  
                }  
            }  
        };  
        ThreadPoolManager.getInstance().addTask(runnable);  
    }  
    return null;  
}  

// 返回圖片存到sd卡的路徑  
public static String getCacheImgPath() {  
    return SDCARD_CACHE_IMG_PATH;  
}  

public static String md5(String paramString) {  
    String returnStr;  
    try {  
        MessageDigest localMessageDigest = MessageDigest.getInstance("MD5");  
        localMessageDigest.update(paramString.getBytes());  
        returnStr = byteToHexString(localMessageDigest.digest());  
        return returnStr;  
    } catch (Exception e) {  
        return paramString;  
    }  
}  

/** 
 * 將指定byte數組轉換成16進制字符串 
 *  
 * @param b 
 * @return 
 */  
public static String byteToHexString(byte[] b) {  
    StringBuffer hexString = new StringBuffer();  
    for (int i = 0; i < b.length; i++) {  
        String hex = Integer.toHexString(b[i] & 0xFF);  
        if (hex.length() == 1) {  
            hex = '0' + hex;  
        }  
        hexString.append(hex.toUpperCase());  
    }  
    return hexString.toString();  
}  

/** 
 *  
 * @author Mathew 
 * 
 */  
public interface ImageCallback{  
    public void loadImage(Bitmap bitmap,String imagePath);  
}  


}  </pre>