I started developing android applications. And am testing with the android emulator. Do I really need android phone before releasing it for public usage?
Short answer No. You can test and build a android application package with the SDK and an emulator. But I would say there are usually many things which it would be wise to test on a device.
Personally I have noticed that the emulator does not give a good indication of response times for UI controls. It is usually necessary to move functionality which has long processing times into background threads to maintain user interactivity without the 'force close' pop-up. Testing the effectiveness of your UI responsiveness must be done on a phone to be meaningful.
Network connectivity is another aspect which can be vastly different on a phone, 3G or wifi.
Device sizes and Android platform versions can be tested effectively on the emulator.
Some phone allow hot-swapping of the SD card (replacing the SDcard without turning off the phone). I am not sure how to replicate this on the emulator.
There may be many more things which may only become apparent when using your application on a real device. I would strongly suggest to always test under real conditions when feasible for any commercial project.
It depends on what type of application you're developing, for serious ones you need at least one device to test it on. For complex applications you would need a range of devices, for example with or without hardware keyboard, different navigational button etc. For basic, simple applications you'll probably do fine with just the emulator.
From a technical perspective there's no reason why you can't develop purely on the emulator. You're not going to be able to test on every available device, so there's always going to be possibility of device specific bugs that you've missed.
However, I'd strongly recommend getting an actual phone to test your application on.
For me the biggest difference between an actual device and the emulator is the difference between using the interface with your fingers and using a mouse. Interactions which make sense in the emulator sometimes don't work as well when you start using touch on the screen. So if you develop purely on an emulator you'll won't lots of little improvements to your UI that would obvious when you used your app on a phone.
You can't feel a real app in your hands until you have a real phone. (I'm telling you as an Android developer)
So, developing w/o real phone is possible, but real phone gives you a lot more experience, fun & usefulness.
I would imagine with games you would definitely need to test on real devices.
Thanks to you all. I am going to get HTC Legend and test it, so that I can hope that my apps can be used by others :)
You guys suggest me HTC Desire or HTC Legend?