any good recommendation of a physical android device for testing purpose?
I am looking for a device like iPod touch in Apple camp that help iOS developer to test their stuff. I know there is Nexus One, but that thing is pretty expensive and i don't really care about the phone stuff, but something that can let developers test accelerometer, touch screen, orientation etc.
any idea?
You could try the official Android unlocked dev phones
But really, you'll want try to get a consumer-grade phone with 2.2 and 1.6, because those are the two main 'camps' I believe in terms of compatibility. Most devices that can run 2.1 will be able to run 2.2, and will eventually update, but a lot of devices running 1.6 won't ever get upgrades IMO. And 1.5 requires a lot of hacks to get things compatible with newer standards.
Here's the official historical distrubution of android versions
How much are you willing to spend? You could get a used Motorola Droid off eBay for maybe $250. If you will never, ever care about the phone features (using it as a phone), you can get a Motorola Droid with a banned ESN (i.e. Verizon will not let it on the cell network) for even less.
Otherwise, the Archos tablets/media players are in the $200-300 range. They can not access the Google Android Marketplace without some sort of hackery, if I recall.
Android devices come with different screen sizes and resolutions so you need to test your device on a number of emulator configurations. For usability testing real device is a must though.
Tablets are not well-suited for testing cause they often have non-standard screen size and resolution. So phone is your only choice. Now you need to choose the phone that allows rooting (some phones such as Motorola Droid series make rooting harder). Finally, take a phone with the latest version which is FroYo (Android 2.2).
If you plan targeting some specific devices, then take that device of course.
If you don't want to spend money, just use the emulator. It's just fine.
If you really want to test the app, get an htc hero with 1.5. It the most incompatible phone I have ever worked with.
I see two ways to choose android device for you:
A. If you haven't statistic from previous version of app.
You should buy device from potentially most popular group of devices for your future app. Currently the most popular devices with Api level 10, screen size normal and hight dpi. See developer.android.com/about/dashboards/index.html
Steps:
B. If you have statistic for your app.
You should find device to cover as more android users as possible for your project.
Steps:
So you should buy device from step 4, which will cover more android users than other.
