占位符和错误处理

Picasso 支持下载和错误占位符作为可选功能。它还提供了处理下载结果的回调。

Picasso.with(context)
  .load("YOUR IMAGE URL HERE")
  .placeholder(Your Drawable Resource)   //this is optional the image to display while the url image is downloading
  .error(Your Drawable Resource)         //this is also optional if some error has occurred in downloading the image this image would be displayed
  .into(imageView, new Callback(){
     @Override
        public void onSuccess() {}

        @Override
        public void onError() {}
   });

在显示错误占位符之前，将重试请求三次。