Does Wi-Fi connection override data connection in Android 4.0 having both on?
Does data connection not get used even though it is enabled, when connected to Wi-Fi router?
Please support your response with a reputable web reference.
Yes. If WiFi is available, Android will use it rather than the mobile-based data connection.
Please support your affirmation with a web article
Sorry, haven't got a web article, but I do have experience of this...
And think about it: given that 3G is available most of the time and in most locations, if there was no prioritisation of WiFi, when would it ever get used?
As Jan mentions, Wi-Fi typically takes priority, but sometimes if the connection isn't working properly, cellular data could be used at the same time or instead, even with Wi-Fi connectivity. This has actually happened to me on several occasions, though I'm having other issues with my rooted phone, as well. Typically, though, this issue did not occur for most users.
Thanks. You mention "isn't working properly". Please tell does this mean low strength or signal stoppage?
The default policy within Android gives WiFi the highest priority. So if you are connected to a WiFi it should get used instead of the mobile data.
However, apps can force a different priority using the ConnectivityManager class.
Thanks. You mention "highest priority". Does this infer that if WiFi signal becomes low , the Data connection overrides Wi-Fi? If yes , what is the Wi-Fi signal strength cut-of point for the reverse overriding?
No, priority has nothing to do with signal strength or anything other technical. It's simply about the availability.
Even if your WiFi signal is so weak you only get 1Mbit speed and it takes 30 seconds to load up Google it will still be preferred over e.g. a 3G or HSPA connection by default.