Picasso使用的方法汇总：

Picasso.with(context).load("http://i.imgur.com/DvpvklR.png").into(imageView);Picasso.with(context).load(url).into(view);Picasso.with(context).load(url) .resize(50, 50).centerCrop().into(imageView)//这里的placeholder将resource传入通过getResource.getDrawable取资源，所以可以是张图片也可以是color idPicasso.with(context).load(url).placeholder(R.drawable.user_placeholder).error(R.drawable.user_placeholder_error).into(imageView);Picasso.with(context).load(R.drawable.landing_screen).into(imageView1);Picasso.with(context).load("file:///android_asset/DvpvklR.png").into(imageView2);Picasso.with(context).load(new File(...)).into(imageView3);//这里显示notification的图片Picasso.with(activity).load(Data.URLS[new Random().nextInt(Data.URLS.length)]).resizeDimen(R.dimen.notification_icon_width_height,R.dimen.notification_icon_width_height).into(remoteViews, R.id.photo, NOTIFICATION_ID, notification);//这里是通过设置tag标签，就是当前传过来的context，这样就可以根据这个context tag来pause和resume显示了Picasso.with(context).load(url).placeholder(R.drawable.placeholder).error(R.drawable.error).fit().tag(context).into(view);//监听onScrollStateChanged的时候调用执行picasso.resumeTag(context);picasso.pauseTag(context);Picasso.with(context).load(contactUri).placeholder(R.drawable.contact_picture_placeholder).tag(context).into(holder.icon);//这个onpause方法里的这段代码还是很有意思的@Override protected void onPause() {    super.onPause();    if (isFinishing()) {      // Always cancel the request here, this is safe to call even if the image has been loaded.      // This ensures that the anonymous callback we have does not prevent the activity from      // being garbage collected. It also prevents our callback from getting invoked even after the      // activity has finished.      Picasso.with(this).cancelRequest(imageView);    }  }// Trigger the download of the URL asynchronously into the image view.    Picasso.with(context)        .load(url)        .placeholder(R.drawable.placeholder)        .error(R.drawable.error)        .resizeDimen(R.dimen.list_detail_image_size, R.dimen.list_detail_image_size)        .centerInside()        .tag(context)        .into(holder.image);//Picasso.with使用的是单例模式Picasso.with(this).cancelTag(this);