Android 如果新图像名称相同,我的imageloder不会更改图像
下面是我的imageloader代码,如果新图像是不同的名称,该代码运行良好,但如果新图像是相同的名称,则不更改图像显示旧图像仅假设我有图像名称,我的图像显示完美,如果我在url中添加具有相同名称的新图像并删除以前的代码,则再次显示以前的图像由于缓存原因而不显示新图像这个代码中的问题请帮助我Android 如果新图像名称相同,我的imageloder不会更改图像,android,Android,下面是我的imageloader代码,如果新图像是不同的名称,该代码运行良好,但如果新图像是相同的名称,则不更改图像显示旧图像仅假设我有图像名称,我的图像显示完美,如果我在url中添加具有相同名称的新图像并删除以前的代码,则再次显示以前的图像由于缓存原因而不显示新图像这个代码中的问题请帮助我 ImageLoader2 imgLoader; String url1 = school2.getJSONObject(0).getString("image");
ImageLoader2 imgLoader;
String url1 = school2.getJSONObject(0).getString("image");
imgLoader.DisplayImage(url1, img1);
public class ImageLoader2 {
MemoryCache2 memoryCache=new MemoryCache2();
FileCache2 fileCache;
private Map<ImageView, String> imageViews=Collections.synchronizedMap(new
WeakHashMap<ImageView, String>());
ExecutorService executorService;
public ImageLoader2(Context context){
fileCache=new FileCache2(context);
executorService=Executors.newFixedThreadPool(5);
}
final int stub_id=R.drawable.ic_launcher;
public void DisplayImage(String url, ImageView imageView)
{
imageViews.put(imageView, url);
Bitmap bitmap=memoryCache.get(url);
if(bitmap!=null)
imageView.setImageBitmap(bitmap);
else
{
queuePhoto(url, imageView);
imageView.setImageResource(stub_id);
}
}
private void queuePhoto(String url, ImageView imageView)
{
PhotoToLoad p=new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url)
{
File f=fileCache.getFile(url);
//from SD cache
Bitmap b = decodeFile(f);
if(b!=null)
return b;
//from web
try {
Bitmap bitmap=null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is=conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
bitmap = decodeFile(f);
return bitmap;
} catch (Throwable ex){
ex.printStackTrace();
if(ex instanceof OutOfMemoryError)
memoryCache.clear();
return null;
}
}
//decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f){
try {
//decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f),null,o);
//Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE=70;
int width_tmp=o.outWidth, height_tmp=o.outHeight;
int scale=1;
while(true){
if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
break;
width_tmp/=2;
height_tmp/=2;
scale*=2;
}
//decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize=scale;
return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
} catch (FileNotFoundException e) {}
return null;
}
//Task for the queue
private class PhotoToLoad
{
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i){
url=u;
imageView=i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad){
this.photoToLoad=photoToLoad;
}
@Override
public void run() {
if(imageViewReused(photoToLoad))
return;
Bitmap bmp=getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if(imageViewReused(photoToLoad))
return;
BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad);
Activity a=(Activity)photoToLoad.imageView.getContext();
a.runOnUiThread(bd);
}
}
boolean imageViewReused(PhotoToLoad photoToLoad){
String tag=imageViews.get(photoToLoad.imageView);
if(tag==null || !tag.equals(photoToLoad.url))
return true;
return false;
}
//Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable
{
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p){bitmap=b;photoToLoad=p;}
public void run()
{
if(imageViewReused(photoToLoad))
return;
if(bitmap!=null)
photoToLoad.imageView.setImageBitmap(bitmap);
else
photoToLoad.imageView.setImageResource(stub_id);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
}
public class MemoryCache2 {
private static final String TAG = "MemoryCache";
private Map<String, Bitmap> cache=Collections.synchronizedMap(
new LinkedHashMap<String, Bitmap>(10,1.5f,true));
private long size=0;//current allocated size
private long limit=1000000;//max memory in bytes
public MemoryCache2(){
//use 25% of available heap size
setLimit(Runtime.getRuntime().maxMemory()/4);
}
public void setLimit(long new_limit){
limit=new_limit;
Log.i(TAG, "MemoryCache will use up to "+limit/1024./1024.+"MB");
}
public Bitmap get(String id){
try{
if(!cache.containsKey(id))
return null;
return cache.get(id);
}catch(NullPointerException ex){
ex.printStackTrace();
return null;
}
}
public void put(String id, Bitmap bitmap){
try{
if(cache.containsKey(id))
size-=getSizeInBytes(cache.get(id));
cache.put(id, bitmap);
size+=getSizeInBytes(bitmap);
checkSize();
}catch(Throwable th){
th.printStackTrace();
}
}
private void checkSize() {
Log.i(TAG, "cache size="+size+" length="+cache.size());
if(size>limit){
Iterator<Entry<String, Bitmap>> iter=cache.entrySet().iterator();
while(iter.hasNext()){
Entry<String, Bitmap> entry=iter.next();
size-=getSizeInBytes(entry.getValue());
iter.remove();
if(size<=limit)
break;
}
Log.i(TAG, "Clean cache. New size "+cache.size());
}
}
public void clear() {
try{
cache.clear();
size=0;
}catch(NullPointerException ex){
ex.printStackTrace();
}
}
long getSizeInBytes(Bitmap bitmap) {
if(bitmap==null)
return 0;
return bitmap.getRowBytes() * bitmap.getHeight();
}
}
private File cacheDir;
public FileCache2(Context context){
//Find the dir to save cached images
if (android.os.Environment.getExternalStorageState().equals
(android.os.Environment.MEDIA_MOUNTED))
cacheDir=new
File(android.os.Environment.getExternalStorageDirectory(),"TTImages_cache");
else
cacheDir=context.getCacheDir();
if(!cacheDir.exists())
cacheDir.mkdirs();
}
public File getFile(String url){
//I identify images by hashcode. Not a perfect solution, good for the demo.
String filename=String.valueOf(url.hashCode());
//Another possible solution (thanks to grantland)
//String filename = URLEncoder.encode(url);
File f = new File(cacheDir, filename);
return f;
}
public void clear(){
File[] files=cacheDir.listFiles();
if(files==null)
return;
for(File f:files)
f.delete();
}
}
imageloader2imgloader;
字符串url1=school2.getJSONObject(0.getString(“图像”);
显示图像(url1,img1);
公共类ImageLoader2{
MemoryCache2 memoryCache=新的MemoryCache2();
文件缓存2文件缓存;
private Map ImageView=Collections.synchronizedMap(新建)
WeakHashMap());
执行服务执行服务;
公共图像加载程序2(上下文){
fileCache=newfilecache2(上下文);
executorService=Executors.newFixedThreadPool(5);
}
最终int stub_id=R.drawable.ic_启动器;
public void DisplayImage(字符串url,ImageView)
{
put(imageView,url);
位图位图=memoryCache.get(url);
if(位图!=null)
设置图像位图(位图);
其他的
{
队列照片(url、imageView);
setImageResource(存根id);
}
}
私有void队列照片(字符串url,ImageView)
{
PhotoToLoad p=新的PhotoToLoad(url,imageView);
executorService.submit(新的PhotoLoader(p));
}
私有位图getBitmap(字符串url)
{
文件f=fileCache.getFile(url);
//从SD缓存
位图b=解码文件(f);
如果(b!=null)
返回b;
//从网络
试一试{
位图=空;
URL imageUrl=新URL(URL);
HttpURLConnection conn=(HttpURLConnection)imageUrl.openConnection();
连接设置连接超时(30000);
连接设置读取超时(30000);
conn.setInstanceFollowRedirects(真);
InputStream is=conn.getInputStream();
OutputStream os=新文件OutputStream(f);
Utils.CopyStream(is,os);
os.close();
位图=解码文件(f);
返回位图;
}捕获(可丢弃的ex){
例如printStackTrace();
if(ex instanceof OutOfMemoryError)
memoryCache.clear();
返回null;
}
}
//对图像进行解码和缩放以减少内存消耗
私有位图解码文件(文件f){
试一试{
//解码图像大小
BitmapFactory.Options o=新的BitmapFactory.Options();
o、 inJustDecodeBounds=true;
解码流(新的FileInputStream(f),null,o);
//找到正确的刻度值。它应该是2的幂。
所需的最终int_尺寸=70;
内部宽度=o.向外宽度,高度=o.向外高度;
int标度=1;
while(true){
如果(宽度_tmp/2使用以下代码加载图像:
使用Android查询。AQuery提供了cahce启用或禁用选项,它比任何ImageLoader类都更快、更准确
您可以从以下链接找到aQuery jar文件:
私用水渠;
AndroidQuery=new AQuery(getActivity())
AndroidQuery.id(您的imageview).image(您的图像值,true,true,默认图标(可选));我已经给了它:
根据下一行给出的代码:
String url1 = school2.getJSONObject(0).getString("image");
**imgLoader.DisplayImage(url1, img1);**
而不是在下面一行:
String url1 = school2.getJSONObject(0).getString("image");
**imgLoader.DisplayImage(url1, img1);**
替换为:
androidAQuery.id(image1).image(url1, true, true,default icon(optional));
Initialize aQuery in your onCreate():
private AQuery androidAQuery; androidAQuery = new AQuery(getActivity());
这是一个工作示例,您只需要将两行代码放入image download和display.androidAQuery.id(您的imageview).image(您可下载的ImageURL、内存缓存(true或false)、文件缓存(true或false)、默认图标(可选));您只需要下载jar文件并将其设置在项目的构建路径上,就完成了。编写程序并输入您所说的im confuseprivate AQuery AndroidQuery;AndroidQuery=new AQuery(getActivity());AndroidQuery.id(您的imageview).image(您的图像值,true,true,默认图标(可选));我已经通过编程编写了它,您只需在希望显示图像的位置编写这两行代码。而不是这一行:String url1=school2.getJSONObject(0.getString(“图像”);imgLoader.DisplayImage(url1,img1);在下面编写代码:private AQuery androidAQuery;androidAQuery=new AQuery(getActivity());AndroidQuery.id(image1).image(url1,true,true);aQuery库在哪里?它会像图像加载器一样自动压缩位图?我在可选中写什么?默认的android图标?这段代码中的image1是什么AndroidQuery.id(image1).image(url1,true,true,默认图标(可选));您的ImageView,我在您的代码中看到过:String url1=school2.getJSONObject(0.getString(“image”);imgLoader.DisplayImage(url1,img1);默认图标用于,当您的图像正在下载过程中时,在此之前将显示一个默认图像,但当您的图像将在那时下载时,它将替换为原始的.androidquery.id(img1).image(url1,true,true,Default icon(可选));默认和(可选显示错误)