content provider其中操作文件的函数
此类函数还是有杀伤力的
1、openAssetFile(Uri uri, String mode)
This is like openFile(Uri, String), but can be implemented by providers that need to be able to return sub-sections of files, often assets inside of their .apk.
2、openFile(Uri uri, String mode)
Override this to handle requests to open a file blob.
3、openTypedAssetFile(Uri uri, String mimeTypeFilter, Bundle opts)
Called by a client to open a read-only stream containing data of a particular MIME type.
http://www.grokkingandroid.com/handling-binary-data-with-contentproviders/
