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图片 缓存
package cn.ibabyzone.library;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import android.app.Activity;
import android.graphics.drawable.Drawable;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
//后台线程下载图片并写入SD卡函数
//如果本地图片存在则直接读取本地文件
public class AsyncImageLoader {
private HashMap<String, SoftReference<Drawable>> imageCache;
private static String SDPATH;
private Activity thisActivity;
public AsyncImageLoader(Activity thisActivity) {
imageCache = new HashMap<String, SoftReference<Drawable>>();
this.thisActivity = thisActivity;
}
public Drawable loadDrawable(final String imageUrl, final ImageCallback imageCallback) {
if (imageCache.containsKey(imageUrl)) {
SoftReference<Drawable> softReference = imageCache.get(imageUrl);
Drawable drawable = softReference.get();
if (drawable != null) {
return drawable;
}
}
final Handler handler = new Handler() {
public void handleMessage(Message message) {
imageCallback.imageLoaded((Drawable) message.obj, imageUrl);
}
};
new Thread() {
@Override
public void run() {
Drawable drawable = loadImageFromUrl(imageUrl,thisActivity);
imageCache.put(imageUrl, new SoftReference<Drawable>(drawable));
Message message = handler.obtainMessage(0, drawable);
handler.sendMessage(message);
}
}.start();
return null;
}
//判断本地文件是否存在存在则读取本地 不存在则下载
//返回数据为图片数据
public static Drawable loadImageFromUrl(String url,Activity thisActivity) {
URL m;
if(android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))
{
SDPATH = Environment.getExternalStorageDirectory() + "/";
}
else
{
SDPATH= thisActivity.getFilesDir().toString() + "/";
}
InputStream i = null;
InputStream j = null;
int urlt = url.lastIndexOf("/");
String imgename = url.substring(urlt+1,url.length()-4);
FileUtils temp =new FileUtils(thisActivity);
String file = "album/"+imgename;
Drawable d=null;
if(temp.isFileExist(file))
{
i =readimage(imgename,thisActivity);
d = Drawable.createFromStream(i, "src");
}
else
{
//if(!temp.isFileExist(file+".temp"))
//{
try {
FileUtils images = new FileUtils(thisActivity);
//Log.e("a",imgename);
images.creatSDFile("album/"+imgename+".temp");
m = new URL(url);
i = (InputStream) m.getContent();
byte[] swapStream ;
swapStream=readStream(i);
InputStream is = new ByteArrayInputStream(swapStream);
d = Drawable.createFromStream(is, "src");
is = new ByteArrayInputStream(swapStream);
images.write2SDFromInput("album/", imgename+".temp", is);
//File files =new File(SDPATH+"yqq/album/"+ imgename+".temp");
//File nfile = new File(SDPATH+"yqq/album/"+imgename);
//files.renameTo(nfile);
moveFile(SDPATH+"yqq/album/"+ imgename+".temp",SDPATH+"yqq/album/"+imgename);
} catch (MalformedURLException e1) {
e1.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//}
}
return d;
}
public static byte[] readStream(InputStream inStream) throws Exception{
ByteArrayOutputStream outStream = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = 0;
while( (len=inStream.read(buffer)) != -1){
outStream.write(buffer, 0, len);
}
outStream.close();
inStream.close();
return outStream.toByteArray();
}
//从本地SD卡中读取已有的图片
public static FileInputStream readimage(String name,Activity thisActivity)
{
InputStream temp;
if(android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))
{
SDPATH = Environment.getExternalStorageDirectory() + "/yqq/";
}
else
{
SDPATH= thisActivity.getFilesDir().toString() + "/yqq/";
}
File file = new File(SDPATH +"album/"+ name);
FileInputStream fis = null;
try {
fis = new FileInputStream(file);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return fis;
}
public static boolean moveFile(String srcFileName, String destDirName) {
File srcFile = new File(srcFileName);
if(!srcFile.exists() || !srcFile.isFile())
return false;
try {
int bytesum = 0;
int byteread = 0;
File oldfile = new File(srcFileName);
if (oldfile.exists()) { //文件存在时
InputStream inStream = new FileInputStream(srcFileName); //读入原文件
FileOutputStream fs = new FileOutputStream(destDirName);
byte[] buffer = new byte[1444];
int length;
while ( (byteread = inStream.read(buffer)) != -1) {
bytesum += byteread; //字节数 文件大小
System.out.println(bytesum);
fs.write(buffer, 0, byteread);
}
inStream.close();
}
}
catch (Exception e) {
return false;
}
return true;
}
//类接口
public interface ImageCallback {
public void imageLoaded(Drawable imageDrawable, String imageUrl);
}
}使用示例：
Drawable cachedImage = asyncImageLoader.loadDrawable(url,
new ImageCallback() {
public void imageLoaded(Drawable imageDrawable,
String imageUrl) {
if (imageDrawable != null) {
adv_image.setImageDrawable(imageDrawable);
int screenWidth = getWindowManager()
.getDefaultDisplay().getWidth();
double bl = (double) imageDrawable
.getMinimumHeight()
/ imageDrawable.getMinimumWidth();
int height = (int) (screenWidth * bl);
adv_image
.setLayoutParams(new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.MATCH_PARENT,
height));
;
waiting_bar.setVisibility(View.GONE);
}
// imageViewByTag.setImageDrawable(imageDrawable);
}
});
if (cachedImage != null) {
adv_image.setImageDrawable(cachedImage);
waiting_bar.setVisibility(View.GONE);
int screenWidth = getWindowManager().getDefaultDisplay()
.getWidth();
double bl = (double) cachedImage.getMinimumHeight()
/ cachedImage.getMinimumWidth();
int height = (int) (screenWidth * bl);
adv_image.setLayoutParams(new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.MATCH_PARENT, height));
}
} else {
// adv_image.setImageResource(R.drawable.no_pic);
waiting_bar.setVisibility(View.GONE);
}
图片 缓存
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