How to monitor SIM state change

Question

I'd like to be able to do some stuff when the SIM state change, i.e. play a sound when SIM PIN is required, but I think there are no Broadcast events that can be intercepted by a broadcast receiver for this... registering for android.intent.action.PHONE_STATE does only tell you when the CALL-STATE changes.. An alternative can be starting a service that registers a PhoneStateListener and reacts upon a LISTEN_SERVICE_STATE (when the state is OUT-OF-STATE it can get the SIM state from the TelephonyManager and look if the state is SIM_STATE_PIN_REQUIRED). So, my questions are:

1) Is there any broadcast intent that I can use to intercept a SIM state change or a Service State change?

2) is it a bad idea to install a PhoneStateListener within a Service and use it to deliver intents to the Service itself upon the notification of a phone state changed received by the PhoneStateListener?

Solution 1

The Intent android.intent.action.SIM_STATE_CHANGED is broadcast when the SIM state changes. For example, on my HTC Desire with a T-Mobile SIM card, if I put the device into flight mode the following Intent is broadcast:

• Intent: android.intent.action.SIM_STATE_CHANGED with extras: ss = NOT_READY, reason = null

If I then take it out of flight mode, the following Intents are broadcast:

• Intent: android.intent.action.SIM_STATE_CHANGED with extras: ss = LOCKED, reason = PIN
• Intent: android.intent.action.SIM_STATE_CHANGED with extras: ss = READY, reason = null
• Intent: android.intent.action.SIM_STATE_CHANGED with extras: ss = IMSI, reason = null
• Intent: android.intent.action.SIM_STATE_CHANGED with extras: ss = LOADED, reason = null

It is possible that different manufacturers and different models behave differently. As they say, "Your mileage may vary".

Solution 2

David's answer is spot on. I wanted to add some example code to help people get started with implementing such a state monitor.

/**
 * Handles broadcasts related to SIM card state changes.
 * <p>
 * Possible states that are received here are:
 * <p>
 * Documented:
 * ABSENT
 * NETWORK_LOCKED
 * PIN_REQUIRED
 * PUK_REQUIRED
 * READY
 * UNKNOWN
 * <p>
 * Undocumented:
 * NOT_READY (ICC interface is not ready, e.g. radio is off or powering on)
 * CARD_IO_ERROR (three consecutive times there was a SIM IO error)
 * IMSI (ICC IMSI is ready in property)
 * LOADED (all ICC records, including IMSI, are loaded)
 * <p>
 * Note: some of these are not documented in
 * https://developer.android.com/reference/android/telephony/TelephonyManager.html
 * but they can be found deeper in the source code, namely in com.android.internal.telephony.IccCardConstants.
 */
public class SimStateChangedReceiver extends BroadcastReceiver {

    /**
     * This refers to com.android.internal.telehpony.IccCardConstants.INTENT_KEY_ICC_STATE.
     * It seems not possible to refer it through a builtin class like TelephonyManager, so we
     * define it here manually.
     */
    private static final String EXTRA_SIM_STATE = "ss";

    @Override
    public void onReceive(Context context, Intent intent) {

        String state = intent.getExtras().getString(EXTRA_SIM_STATE);
        if (state == null) {
            return;
        }

        // Do stuff depending on state   
        switch (state) {      
            case "ABSENT": break;
            case "NETWORK_LOCKED": break;
            // etc.
        }
    }
}

Solution 3

The second approach of having a PhoneStateListener in a Service that listens for onServiceStateChanged() worked for me. I believe that on some devices you will not get the internal broadcast android.intent.action.SIM_STATE_CHANGED.