Android 异步获取图片并缓存到本地

publicclassAsyncBitmapLoader

{

/**

*内存图片软引用缓冲

*/

privateHashMap<String,SoftReference<Bitmap>>imageCache=null;

publicAsyncBitmapLoader()

{

imageCache=newHashMap<String,SoftReference<Bitmap>>();

}

publicBitmaploadBitmap(finalImageViewimageView,finalStringimageURL,finalImageCallBackimageCallBack)

{

//在内存缓存中，则返回Bitmap对象

if(imageCache.containsKey(imageURL))

{

SoftReference<Bitmap>reference=imageCache.get(imageURL);

Bitmapbitmap=reference.get();

if(bitmap!=null)

{

returnbitmap;

}

}

else

{

/**

*加上一个对本地缓存的查找

*/

StringbitmapName=imageURL.substring(imageURL.lastIndexOf("/")+1);

FilecacheDir=newFile("/mnt/sdcard/test/");

File[]cacheFiles=cacheDir.listFiles();

inti=0;

if(null!=cacheFiles){

for(;i<cacheFiles.length;i++)

{

if(bitmapName.equals(cacheFiles[i].getName()))

{

break;

}

}

if(i<cacheFiles.length)

{

returnBitmapFactory.decodeFile("/mnt/sdcard/test/"+bitmapName);

}

}

}

finalHandlerhandler=newHandler()

{

/*(non-Javadoc)

*@seeandroid.os.Handler#handleMessage(android.os.Message)

*/

@Override

publicvoidhandleMessage(Messagemsg)

{

//TODOAuto-generatedmethodstub

imageCallBack.imageLoad(imageView,(Bitmap)msg.obj);

}

};

//如果不在内存缓存中，也不在本地（被jvm回收掉），则开启线程下载图片

newThread()

{

/*(non-Javadoc)

*@seejava.lang.Thread#run()

*/

@Override

publicvoidrun()

{

//TODOAuto-generatedmethodstub

InputStreambitmapIs=HttpUtils.getStreamFromURL(imageURL);

Bitmapbitmap=BitmapFactory.decodeStream(bitmapIs);

imageCache.put(imageURL,newSoftReference<Bitmap>(bitmap));

Messagemsg=handler.obtainMessage(0,bitmap);

handler.sendMessage(msg);

Filedir=newFile("/mnt/sdcard/test/");

if(!dir.exists())

{

dir.mkdirs();

}

FilebitmapFile=newFile("/mnt/sdcard/test/"+

imageURL.substring(imageURL.lastIndexOf("/")+1));

if(!bitmapFile.exists())

{

try

{

bitmapFile.createNewFile();

}

catch(IOExceptione)

{

//TODOAuto-generatedcatchblock

e.printStackTrace();

}

}

FileOutputStreamfos;

try

{

fos=newFileOutputStream(bitmapFile);

bitmap.compress(Bitmap.CompressFormat.PNG,

100,fos);

fos.close();

}

catch(FileNotFoundExceptione)

{

//TODOAuto-generatedcatchblock

e.printStackTrace();

}

catch(IOExceptione)

{

//TODOAuto-generatedcatchblock

e.printStackTrace();

}

}

}.start();

returnnull;

}

publicinterfaceImageCallBack

{

publicvoidimageLoad(ImageViewimageView,Bitmapbitmap);

}

}