how to check wifi or 3g network is available on android device

I use this:

/**
 * Checks if we have a valid Internet Connection on the device.
 * @param ctx
 * @return True if device has internet
 *
 * Code from: http://www.androidsnippets.org/snippets/131/
 */
public static boolean haveInternet(Context ctx) {

    NetworkInfo info = (NetworkInfo) ((ConnectivityManager) ctx
            .getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();

    if (info == null || !info.isConnected()) {
        return false;
    }
    if (info.isRoaming()) {
        // here is the roaming option you can change it if you want to
        // disable internet while roaming, just return false
        return false;
    }
    return true;
}

You also need

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

in AndroidMainfest.xml

To get the network type you can use this code snippet:

ConnectivityManager conMan = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

//mobile
State mobile = conMan.getNetworkInfo(0).getState();

//wifi
State wifi = conMan.getNetworkInfo(1).getState();

and then use it like that:

if (mobile == NetworkInfo.State.CONNECTED || mobile == NetworkInfo.State.CONNECTING) {
    //mobile
} else if (wifi == NetworkInfo.State.CONNECTED || wifi == NetworkInfo.State.CONNECTING) {
    //wifi
}

To get the type of the mobile network I would try TelephonyManager#getNetworkType or NetworkInfo#getSubtypeName