assets: will not generate the corresponding tag under r.java file, assets folder is not created by default need to create their own folder and resource folder with the same parent directory, using the AssetsManager class to access, stored here when running the packaging of resources will be entered into the program installation package.
resource : the tag will be generated under the r.java file. The resource here will determine what is used when running the packaging operation. The file resources that are not used will not be packaged into the installation package . The file using resource is called by the R class according to the path