Android 3G/2G control API?

On Android settings, under Wireless controls->Mobile networks there is a setting "Use only 2G networ开发者_StackOverflowks".

In the Android SDK reference, under android.telephony.TelephonyManager, there doesn't seem to be anything to control the network type.

What APIs does this setting actually call?

It appears to call com.android.internal.telephony.Phone.setPreferredNetworkType(). Since it is "internal", it isn't available to applications via the SDK.

See:

https://android.googlesource.com/platform/packages/apps/Phone/+/master/src/com/android/phone/Use2GOnlyCheckBoxPreference.java