BJUG9

This app is a demo for the "Work with the OS, not against it" section of the "Building Good Android Apps" talk at BJUG#9.

The purpose of this app is to demonstrate in a simple way how you can use features that the Android OS provides you with in order to create a better user experience. It does this by showing a simple ListView, allowing you to switch between four ListAdapters, each one having 10,000 items:

1. BadAdapter is what would be your first attempt at writing a list adpater. It's bad because it creates a View object (by inflating a layout file) for every list item, not taking advantage of the provided convertView.
2. GoodAdapter uses the convertView object, thus greatly reducing the number of objects created by the adapter. This sensibly improves the performance of the app.
3. AwesomeAdapter implements a trick using the setTag() and getTag() methods present on the View object so that it can greatly reduce the number of calls to findViewById(), which is pretty expensive.
4. TwoToneAdapter shows that you don't need to throw these optimizations away when you're doing something more complicated, like having multiple view types in your adapter. All you need to do is implement a couple extra methods so that Android knows what your intentions are.

Building

If you're feeling adventurous, playing with the code is pretty straightforward. Install the Android SDK (if you haven't done so already) and it should be a simple matter of File > Import > General > Existing Projects into Workspace.