I have noticed on the official Android blog that WiFi Direct APIs are supported on google phone which are having versions 4.0 or later. Also I have seen the code to access WiFi Direct API. But I have doubt that on some blogs people have written that some 2.3 version android devices also support WiFi Direct. So same code we are writing for 4.0 or later , will work on the 2.3 version android devices which support WiFi Direct?. I have failed to find the code which is compatible to android version 2.3
Again I have noticed ,Alternate solution for this is "AllJoyn" (https://www.alljoyn.org/) , but don't know that is it the right way to use WiFi Direct ?
Can anybody please help me ?
The fact that a device supports WiFi Direct (eg: version 2.3) doesn't necessarily mean that you have access to the WiFi Direct API (available from 4.0)
On the version 2.3 examples, consider that the feature is there but the app developer can't directly interact with it. I think that on the blogs you are talking about, the guys have just enabled the WiFi Direct on 2.3 but don't do anything by code. If you want to do something by code with WiFi Direct, you need a device WD enabled and which runs on 4.0 at least so you have access to the API.
AllJoyn won't solve your problem. AllJoyn provides a layer on top of the transport APIs so the developer doesn't have to care if the data will be transferred via Bluetooth, WIFi legacy or WiFi Direct.
来源：https://stackoverflow.com/questions/12000286/wifi-direct-for-android-version-2-3