I am new to Android App Development. (Did a year back but completely forgot)
A year back I had created a Virtual Device and I had setup the Emulator using the AVD Manager. Back then, it only asked me to choose the Target and I chose 2.2 everytime so that it supported in the latest versions too.
One year down the lane, the problem I am facing is, it is asking me to choose a target device too. I use a Galaxy Fit but there are other people with different handsets and resolutions for tablets, smartphones, notes, etc. I referred to all the tutorials on YouTube, Google and the Android Documentation itself, it only gives information about the old setup, the one without Device information.
I want to know which device to choose so that my app can be compatible on all devices and screen sizes(I chose Android 2.2 for the target) because without choosing the Device, the OK button is not getting activated.
Thank You
Making an app to be compatible with all devices depends on how you design your app, not on the virtual device chosen.
Some recommended Android documentation on how to polish your app for different screens can be found here.
Regarding sensors or other features that may be present or not in some devices, you should check if they are available before making use of them.
If you follow those, you are probably in a good position to be compatible with the phones that support the minimum API set you have chosen.
However, testing in different virtual devices can help you verify that your app is compatible in different real devices.
By the way, the device option when creating an AVD is for creating an AVD that matches a specific device (there is a question about it here). However for compatibility, you do not need to test specific devices, but a wide range of features values (resolution, screens, and on)