Some phones have Wifi Direct apps while having Android OS 2.3.x. But Wifi direct APIs is supported by Android 4.0 or later.
So Can I develop(code) for Wifi direct with Android 2.3, is there any such library or way to do so (for e.g using NDK or else)? Pls give the links or detail! Thanks.
You should see the following links:
WiFi Direct for Android Version 2.3+.
can we have wifi direct api working in 2.3 version.
The answer is NO. You can use built-in wifi direct apps in devices with Android 2.3. Note that in official website, Google only supports Wifi Direct API from Android 4.0.