缓存接口

ImageCache：

public interface ImageCache{	public Bitmap get(String url);	public void put(String url,Bitmap bitmap);}复制代码

内存缓存

MemoryCache：

public class MemoryCache implements ImageCache{	private LruCache
    
      mMemoryCache;	public MemoryCache()	{		initImageCache();	}	private void initImageCache()	{		//计算可使用的最大内存		final int maxMemory = (int)(Runtime.getRuntime().maxMemory() / 1024);		//取1/4作为缓存		final int cacheSize = maxMemory / 4;		mMemoryCache = new LruCache
     
      (cacheSize)		{			@Override			protected int sizeOf(String key, Bitmap value)			{				return value.getRowBytes() * value.getHeight() / 4;			}		};	}	@Override	public Bitmap get(String url)	{		return mMemoryCache.get(url);	}	@Override	public void put(String url, Bitmap bitmap)	{		mMemoryCache.put(url,bitmap);	}}复制代码
     
    

磁盘缓存

DiskCache ：

public class DiskCache implements ImageCache{	static String cacheDir = "sdcard/cache/";	@Override	public Bitmap get(String url)	{		return BitmapFactory.decodeFile(cacheDir+url);	}	@Override	public void put(String url, Bitmap bmp)	{		FileOutputStream fileOutputStream = null;		try		{			fileOutputStream = new FileOutputStream(cacheDir + url);			bmp.compress(Bitmap.CompressFormat.PNG, 100, fileOutputStream);		}		catch(Exception e)		{			e.printStackTrace();		}		finally		{			CloseUtils.closeQuitely(fileOutputStream);			if(fileOutputStream != null)			{				try				{					fileOutputStream.close();				}				catch(IOException e)				{					e.printStackTrace();				}			}		}	}}复制代码

流工具

CloseUtils：

public class CloseUtils{	private CloseUtils(){}	/**	 * 关闭closeable对象	 * @param closeable	 */	public static void closeQuitely(Closeable closeable){		if(closeable != null){			try			{				closeable.close();			}			catch(IOException e)			{				e.printStackTrace();			}		}	}}复制代码

双缓存实现

DoubleCache ：

/** * 双缓存，获取图片先从内存，内存没有在从sdcard获取 * 缓存时在内存和sdcard各缓存一份 */public class DoubleCache implements ImageCache{	private MemoryCache mMemoryCache = new MemoryCache();	private DiskCache mDiskCache = new DiskCache();	@Override	public Bitmap get(String url)	{		Bitmap bitmap = mMemoryCache.get(url);		if(bitmap == null){			bitmap = mDiskCache.get(url);		}		return bitmap;	}	@Override	public void put(String url, Bitmap bitmap)	{		mMemoryCache.put(url,bitmap);		mDiskCache.put(url,bitmap);	}}复制代码

图片加载器的实现

ImageLoader：

public class ImageLoader{	//内存缓存	private ImageCache mImageCache = new MemoryCache();	//线程池，个数为cpu的数量	private ExecutorService mExecutorService = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());	/**	 * 注入缓存实现	 * @param cache	 */	public void setImageCache(ImageCache cache){		this.mImageCache = cache;	}	//加载图片	public void displayImage(String url, ImageView imageView){		Bitmap bitmap = mImageCache.get(url);		if(bitmap != null){			imageView.setImageBitmap(bitmap);			return;		}		//没有缓存提交到线程池下载图片		submitLoadRequest(url,imageView);	}	private void submitLoadRequest(final String url, final ImageView imageView)	{		imageView.setTag(url);		mExecutorService.submit(new Runnable()		{			@Override			public void run()			{				Bitmap bitmap = downloadImage(url);				if(bitmap == null){					return;				}				if(imageView.getTag().equals(url)){					imageView.setImageBitmap(bitmap);				}				mImageCache.put(url,bitmap);			}		});	}	/**	 * 下载图片	 * @param imageUrl	 * @return	 */	private Bitmap downloadImage(String imageUrl)	{		Bitmap mBitmap = null;		try		{			URL url = new URL(imageUrl);			final HttpURLConnection conn = (HttpURLConnection)url.openConnection();			mBitmap = BitmapFactory.decodeStream(conn.getInputStream());			conn.disconnect();		}		catch(Exception e)		{			e.printStackTrace();		}		return mBitmap;	}}复制代码