Android: How to check whether 3G is enabled or not

问题:

I need to know whether 3G connectivity is permitted on the device or not. I don't want to know what current network state is, because if you set "Network Mode" setting in "Mobile network settings" screen to "Automatic" network state could be either 2G or 3G. I just want to know which setting is selected there - 2G, 3G or Automatic (latter two mean the same for me).

Both telephonyManager.getNetworkType() and ConnectivityManage.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState()

are returning current network state, which can lead me in a wrong direction, because if current state is 2G it could mean that 3G is disabled or just that 3G mode is unavailable at the specific location.

回答1:

Updated after test on LG GT540 phone:

You can use Settings.Secure to read preferred network mode, as in this code:

ContentResolver cr = getContentResolver();
int value = Secure.getInt(cr, "preferred_network_mode");

On my LG GT540 with CM 7.1 firmware, I have four options:

• GSM/WCDM (auto) - the code above returns 3
• WCDMA only - the code above returns 2
• GSM only - the code above returns 1
• GMS/WCDMA (WCMDA preferred) - the code above returns 0

Naturally, GSM is 2G and WCDMA is 3G. Note that this does not provide you with information on which connection is currently active (provided you allow both). For that, see @VikashKLumar's answer.

回答2:

you can check the 3G by using

boolean is3G3 = (telephonyManager.getNetworkType() == TelephonyManager.NETWORK_TYPE_HSUPA);
boolean is3G2 = (telephonyManager.getNetworkType() == TelephonyManager.NETWORK_TYPE_HSPA);
boolean is3G = (telephonyManager.getNetworkType() == TelephonyManager.NETWORK_TYPE_HSDPA);

These networks are 3G networks.

回答3:

Just dial ×#×#4636#×#× go into phone information and see down if there is GSM only your phone would not support 3G and if It's WCDMA prefferd your phone can use 3G

回答4:

/**
 * 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