Picasso图片库缓存

使用方法非常简单就一句话

Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView); 

点击下载Picasso的Jar文件

Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView)的过程：

public static Picasso with(Context context) {  
        if (singleton == null) {  
            singleton = new Builder(context).build();  
        }  
        return singleton;  
    }  
      
    public Picasso build() {  
            Context context = this.context;  
  
            if (downloader == null) {  
                downloader = Utils.createDefaultDownloader(context);  
            }  
            if (cache == null) {  
                cache = new LruCache(context);  
            }  
            if (service == null) {  
                service = new PicassoExecutorService();  
            }  
            if (transformer == null) {  
                transformer = RequestTransformer.IDENTITY;  
            }  
  
            Stats stats = new Stats(cache);  
  
            Dispatcher dispatcher = new Dispatcher(context, service, HANDLER,  
                    downloader, cache, stats);  
  
            return new Picasso(context, dispatcher, cache, listener,  
                    transformer, stats, debugging);  
        }