How to setup imports for a dart/polymer project (in general and for BWU-datagrid)

Question

I've tried examples from Learning Dart, the Dart website, Up and Running and I can't get this to work. I've read and tried everything I know to and I still do not understand dart imports.

I am simply trying to setup my own bwu_datagrid and I finding the imports to be impossible because when I do what is suggested or I run the exact code from say the Learning Dart examples and it doesn't work.

So can someone explain to me, in detail, what I need to do to make a dart project where a bwu_datagrid is rendered on screen without error.

my project structure is:

• /root
  • /packages
    • /bwu_datagrid
    • /polymer
    • ...other packages
  • /lib
    • /src
      • some_part.dart
    • some_library.dart
  • /web
    • index.html

Answer 1

There are different types of imports:

• import 'dart:blah'; Imports from the Dart SDK, eg. dart:html
• import 'package:blah/something.dart'; Imports from a package that you've included via Pub (in your pubspec.yaml), which will appear as a symlink inside your packages folders (which get symlinked in several places, like bin\packages and web\packages
• import 'path/file.dart'; Imports a file from the file system using a relative path

Something that confused me at first, is that if you want to import something from your own project without putting a path that's relative to where the including file is, you can import using a package: prefix and your own project name. This works, because Pub creates a symlink for your own project inside the packages folder.

Eg.:

my_project\web\packages\my_project is a symlink back to my_project\lib so that you can do:

import 'package:my_project/my_stuff.dart';

So, in order to import something from bwu_datagrid, which is a pub package, you need to do:

import 'package:bwu_datagrid/somefile.dart';

You need to replace somefile.dart with the correct file that you need to include, as you do not import "packages" directly; but rather files from within them.