Detecting “use only 2G networks” setting

Question

Is there a way of returning the value of Android\'s mobile network setting for \"use only 2G networks\"?

The app being developed measures the internet speed at a certain

Answer 1

For a small subset of devices (specifically for the LG Optimus 2X Speed, LG-P990), an answer seems to be:

int enabled = Settings.Secure.getInt(getContentResolver(),
        "preferred_network_mode", -1);
Log.d("MYAPP", "2G only enabled: " + enabled);

Where the "use only 2G networks" setting is specified as:

• 0 indicates the setting is disabled
• 1 indicates the setting is enabled
• -1 indicates the setting is not set (some devices?)

How I discovered this? I gathered all the key/value pairs from Settings.Secure using the following:

ContentResolver cr = getContentResolver();
Cursor cursor = cr.query(Settings.Secure.CONTENT_URI, null, null, null, null);
if (cursor.moveToFirst()) {
    while (!cursor.isAfterLast()) {
        Log.d("MYAPP", "cursor: "
                + cursor.getString(0) + ", "
                + cursor.getString(1) + ", "
                + cursor.getString(2));
        cursor.moveToNext();
    }
}

I compared results between enabling and disabling the setting, and sure enough I got:

07-08 00:15:20.991: DEBUG/MYAPP(13813): cursor: 5154, preferred_network_mode, 1

Do NOT use the index column (5154 in the example above), as I've noticed it changes between toggling the setting.

Although this correlates with some documentation for Settings.Secure I found online, this value isn't respected by all phones.

If your device returns -1, perhaps listing the key value pairs will reveal which setting you need. Please comment if you encounter it!

Answer 2

As far as I can tell, there is no documented way of getting value for that setting. But there is a Use2GOnlyCheckBoxPreference class that can be used as an example. It uses internal Phone and PhoneFactory classes to obtain the current value of prefer_2g setting.

You can use Phone and PhoneFactory classes via reflection. But of cause this is undocumented and is on your own risk. Here is relevant code from Use2GOnlyCheckBoxPreference:

import com.android.internal.telephony.Phone;
import com.android.internal.telephony.PhoneFactory;

public class Use2GOnlyCheckBoxPreference extends CheckBoxPreference {

    private Phone mPhone;
    private MyHandler mHandler;

    public Use2GOnlyCheckBoxPreference(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mPhone = PhoneFactory.getDefaultPhone();
        mHandler = new MyHandler();
        mPhone.getPreferredNetworkType(
                mHandler.obtainMessage(MyHandler.MESSAGE_GET_PREFERRED_NETWORK_TYPE));
    }

    private class MyHandler extends Handler {

        private static final int MESSAGE_GET_PREFERRED_NETWORK_TYPE = 0;

        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case MESSAGE_GET_PREFERRED_NETWORK_TYPE:
                    handleGetPreferredNetworkTypeResponse(msg);
                    break;
            }
        }

        private void handleGetPreferredNetworkTypeResponse(Message msg) {
            AsyncResult ar = (AsyncResult) msg.obj;

            if (ar.exception == null) {
                int type = ((int[])ar.result)[0];
                Log.i(LOG_TAG, "get preferred network type="+type);
                setChecked(type == Phone.NT_MODE_GSM_ONLY);
            } else {
                // Weird state, disable the setting
                Log.i(LOG_TAG, "get preferred network type, exception="+ar.exception);
                setEnabled(false);
            }
        }
    }   
}