Android telephony Manager gives you access to information about the device's telephonic services. The methods in this class can be used by applications to determine telephone services and statuses, as well as to access specific forms of subscriber data. Applications can additionally register a listener to be notified of changes in the telephony state.
For all calls, the returning TelephonyManager will utilise the default subscription. For calling any API related to a specific subscription, use the method: createForSubscriptionId (int). For example, telephonyManager = defaultSubTelephonyManager.createForSubscriptionId(subId);
It's worth noting that some telephonic data is password-protected. Unless the right permissions are indicated in your manifest file, your application will not be able to access the protected information. Permissions are noted in the means by which you access the protected information when they apply.
TelephonyManager is designed to work with devices that have FEATURE TELEPHONY enabled. The behavior is unreliable on devices that do not support this functionality.
TelephonyManager (Int Ptr, JnuHandleOwnership): It is a constructor which is used for the creation of managed representations of the JNI objects. These are called by the runtime.
Here are the key fields available in the Android Telephony manager: