Merge changes from topic "satellite-state-change-listener" into main

* changes:
  Add READ_BASIC_PHONE_STATE permission to Shell for CTS
  Implements satellite state change listener APIs
  Introduce satellite state change listener APIs
  Expose SatelliteManager as public manager class
diff --git a/core/api/current.txt b/core/api/current.txt
index 4b90f72..39d086a 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -10949,6 +10949,7 @@
     field public static final int RECEIVER_VISIBLE_TO_INSTANT_APPS = 1; // 0x1
     field public static final String RESTRICTIONS_SERVICE = "restrictions";
     field public static final String ROLE_SERVICE = "role";
+    field @FlaggedApi("com.android.internal.telephony.flags.satellite_state_change_listener") public static final String SATELLITE_SERVICE = "satellite";
     field public static final String SEARCH_SERVICE = "search";
     field @FlaggedApi("android.os.security_state_service") public static final String SECURITY_STATE_SERVICE = "security_state";
     field public static final String SENSOR_SERVICE = "sensor";
@@ -47866,6 +47867,19 @@
 
 }
 
+package android.telephony.satellite {
+
+  @FlaggedApi("com.android.internal.telephony.flags.satellite_state_change_listener") public final class SatelliteManager {
+    method @FlaggedApi("com.android.internal.telephony.flags.satellite_state_change_listener") @RequiresPermission(anyOf={android.Manifest.permission.READ_BASIC_PHONE_STATE, "android.permission.READ_PRIVILEGED_PHONE_STATE", android.Manifest.permission.READ_PHONE_STATE, "carrier privileges"}) public void registerStateChangeListener(@NonNull java.util.concurrent.Executor, @NonNull android.telephony.satellite.SatelliteStateChangeListener);
+    method @FlaggedApi("com.android.internal.telephony.flags.satellite_state_change_listener") @RequiresPermission(anyOf={android.Manifest.permission.READ_BASIC_PHONE_STATE, "android.permission.READ_PRIVILEGED_PHONE_STATE", android.Manifest.permission.READ_PHONE_STATE, "carrier privileges"}) public void unregisterStateChangeListener(@NonNull android.telephony.satellite.SatelliteStateChangeListener);
+  }
+
+  @FlaggedApi("com.android.internal.telephony.flags.satellite_state_change_listener") public interface SatelliteStateChangeListener {
+    method public void onEnabledStateChanged(boolean);
+  }
+
+}
+
 package android.text {
 
   @Deprecated public class AlteredCharSequence implements java.lang.CharSequence android.text.GetChars {
diff --git a/core/api/system-current.txt b/core/api/system-current.txt
index e202bfb..e4d5589 100644
--- a/core/api/system-current.txt
+++ b/core/api/system-current.txt
@@ -18253,7 +18253,7 @@
     method @FlaggedApi("com.android.internal.telephony.flags.oem_enabled_satellite_flag") public void onSatelliteDatagramReceived(long, @NonNull android.telephony.satellite.SatelliteDatagram, int, @NonNull java.util.function.Consumer<java.lang.Void>);
   }
 
-  public final class SatelliteManager {
+  @FlaggedApi("com.android.internal.telephony.flags.satellite_state_change_listener") public final class SatelliteManager {
     method @FlaggedApi("com.android.internal.telephony.flags.carrier_enabled_satellite_flag") @RequiresPermission(android.Manifest.permission.SATELLITE_COMMUNICATION) public void addAttachRestrictionForCarrier(int, int, @NonNull java.util.concurrent.Executor, @NonNull java.util.function.Consumer<java.lang.Integer>);
     method @FlaggedApi("com.android.internal.telephony.flags.oem_enabled_satellite_flag") @RequiresPermission(android.Manifest.permission.SATELLITE_COMMUNICATION) public void deprovisionService(@NonNull String, @NonNull java.util.concurrent.Executor, @NonNull java.util.function.Consumer<java.lang.Integer>);
     method @FlaggedApi("com.android.internal.telephony.flags.carrier_enabled_satellite_flag") @NonNull @RequiresPermission(android.Manifest.permission.SATELLITE_COMMUNICATION) public java.util.Set<java.lang.Integer> getAttachRestrictionReasonsForCarrier(int);
diff --git a/core/java/android/content/Context.java b/core/java/android/content/Context.java
index 1d26b77..186f7b3 100644
--- a/core/java/android/content/Context.java
+++ b/core/java/android/content/Context.java
@@ -6677,8 +6677,8 @@
      *
      * @see #getSystemService(String)
      * @see android.telephony.satellite.SatelliteManager
-     * @hide
      */
+    @FlaggedApi(com.android.internal.telephony.flags.Flags.FLAG_SATELLITE_STATE_CHANGE_LISTENER)
     public static final String SATELLITE_SERVICE = "satellite";
 
     /**
diff --git a/core/java/android/telephony/TelephonyRegistryManager.java b/core/java/android/telephony/TelephonyRegistryManager.java
index 4d50a45..1dab2cf 100644
--- a/core/java/android/telephony/TelephonyRegistryManager.java
+++ b/core/java/android/telephony/TelephonyRegistryManager.java
@@ -47,6 +47,8 @@
 import android.telephony.ims.ImsCallSession;
 import android.telephony.ims.ImsReasonInfo;
 import android.telephony.ims.MediaQualityStatus;
+import android.telephony.satellite.SatelliteStateChangeListener;
+import android.util.ArrayMap;
 import android.util.ArraySet;
 import android.util.Log;
 
@@ -55,12 +57,14 @@
 import com.android.internal.telephony.ICarrierConfigChangeListener;
 import com.android.internal.telephony.ICarrierPrivilegesCallback;
 import com.android.internal.telephony.IOnSubscriptionsChangedListener;
+import com.android.internal.telephony.ISatelliteStateChangeListener;
 import com.android.internal.telephony.ITelephonyRegistry;
 import com.android.server.telecom.flags.Flags;
 
 import java.lang.ref.WeakReference;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
 import java.util.WeakHashMap;
@@ -1482,6 +1486,111 @@
                 pkgName, attributionTag, callback, new int[0], notifyNow);
     }
 
+    @NonNull
+    @GuardedBy("sSatelliteStateChangeListeners")
+    private static final Map<SatelliteStateChangeListener,
+                WeakReference<SatelliteStateChangeListenerWrapper>>
+            sSatelliteStateChangeListeners = new ArrayMap<>();
+
+    /**
+     * Register a {@link SatelliteStateChangeListener} to receive notification when Satellite state
+     * has changed.
+     *
+     * @param executor The {@link Executor} where the {@code listener} will be invoked
+     * @param listener The listener to monitor the satellite state change
+     * @hide
+     */
+    public void addSatelliteStateChangeListener(@NonNull @CallbackExecutor Executor executor,
+            @NonNull SatelliteStateChangeListener listener) {
+        if (listener == null || executor == null) {
+            throw new IllegalArgumentException("Listener and executor must be non-null");
+        }
+
+        synchronized (sSatelliteStateChangeListeners) {
+            WeakReference<SatelliteStateChangeListenerWrapper> existing =
+                    sSatelliteStateChangeListeners.get(listener);
+            if (existing != null && existing.get() != null) {
+                Log.d(TAG, "addSatelliteStateChangeListener: listener already registered");
+                return;
+            }
+            SatelliteStateChangeListenerWrapper wrapper =
+                    new SatelliteStateChangeListenerWrapper(executor, listener);
+            try {
+                sRegistry.addSatelliteStateChangeListener(
+                        wrapper,
+                        mContext.getOpPackageName(),
+                        mContext.getAttributionTag());
+                sSatelliteStateChangeListeners.put(listener, new WeakReference<>(wrapper));
+            } catch (RemoteException e) {
+                throw e.rethrowFromSystemServer();
+            }
+        }
+    }
+
+    /**
+     * Unregister a {@link SatelliteStateChangeListener} to stop receiving notification when
+     * satellite state has changed.
+     *
+     * @param listener The listener previously registered with addSatelliteStateChangeListener.
+     * @hide
+     */
+    public void removeSatelliteStateChangeListener(@NonNull SatelliteStateChangeListener listener) {
+        if (listener == null) {
+            throw new IllegalArgumentException("listener must be non-null");
+        }
+
+        synchronized (sSatelliteStateChangeListeners) {
+            WeakReference<SatelliteStateChangeListenerWrapper> ref =
+                    sSatelliteStateChangeListeners.get(listener);
+            if (ref == null) return;
+            SatelliteStateChangeListenerWrapper wrapper = ref.get();
+            if (wrapper == null) return;
+            try {
+                sRegistry.removeSatelliteStateChangeListener(wrapper, mContext.getOpPackageName());
+                sSatelliteStateChangeListeners.remove(listener);
+            } catch (RemoteException e) {
+                throw e.rethrowFromSystemServer();
+            }
+        }
+    }
+
+    /**
+     * Notify the registrants that the satellite state has changed.
+     *
+     * @param isEnabled True if the satellite modem is enabled, false otherwise
+     * @hide
+     */
+    public void notifySatelliteStateChanged(boolean isEnabled) {
+        try {
+            sRegistry.notifySatelliteStateChanged(isEnabled);
+        } catch (RemoteException ex) {
+            // system process is dead
+            throw ex.rethrowFromSystemServer();
+        }
+    }
+
+    private static class SatelliteStateChangeListenerWrapper extends
+            ISatelliteStateChangeListener.Stub implements ListenerExecutor {
+        @NonNull private final WeakReference<SatelliteStateChangeListener> mListener;
+        @NonNull private final Executor mExecutor;
+
+        SatelliteStateChangeListenerWrapper(@NonNull Executor executor,
+                @NonNull SatelliteStateChangeListener listener) {
+            mExecutor = executor;
+            mListener = new WeakReference<>(listener);
+        }
+
+        @Override
+        public void onSatelliteEnabledStateChanged(boolean isEnabled) {
+            Binder.withCleanCallingIdentity(
+                    () ->
+                            executeSafely(
+                                    mExecutor,
+                                    mListener::get,
+                                    sscl -> sscl.onEnabledStateChanged(isEnabled)));
+        }
+    }
+
     private static class CarrierPrivilegesCallbackWrapper extends ICarrierPrivilegesCallback.Stub
             implements ListenerExecutor {
         @NonNull private final WeakReference<CarrierPrivilegesCallback> mCallback;
diff --git a/core/java/com/android/internal/telephony/ISatelliteStateChangeListener.aidl b/core/java/com/android/internal/telephony/ISatelliteStateChangeListener.aidl
new file mode 100644
index 0000000..4d195c2
--- /dev/null
+++ b/core/java/com/android/internal/telephony/ISatelliteStateChangeListener.aidl
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.internal.telephony;
+
+oneway interface ISatelliteStateChangeListener {
+    void onSatelliteEnabledStateChanged(boolean isEnabled);
+}
\ No newline at end of file
diff --git a/core/java/com/android/internal/telephony/ITelephonyRegistry.aidl b/core/java/com/android/internal/telephony/ITelephonyRegistry.aidl
index ca75abd..1c76a6c 100644
--- a/core/java/com/android/internal/telephony/ITelephonyRegistry.aidl
+++ b/core/java/com/android/internal/telephony/ITelephonyRegistry.aidl
@@ -38,6 +38,7 @@
 import com.android.internal.telephony.ICarrierPrivilegesCallback;
 import com.android.internal.telephony.IPhoneStateListener;
 import com.android.internal.telephony.IOnSubscriptionsChangedListener;
+import com.android.internal.telephony.ISatelliteStateChangeListener;
 
 interface ITelephonyRegistry {
     void addOnSubscriptionsChangedListener(String pkg, String featureId,
@@ -124,4 +125,8 @@
     void notifyCarrierRoamingNtnModeChanged(int subId, in boolean active);
     void notifyCarrierRoamingNtnEligibleStateChanged(int subId, in boolean eligible);
     void notifyCarrierRoamingNtnAvailableServicesChanged(int subId, in int[] availableServices);
+
+    void addSatelliteStateChangeListener(ISatelliteStateChangeListener listener, String pkg, String featureId);
+    void removeSatelliteStateChangeListener(ISatelliteStateChangeListener listener, String pkg);
+    void notifySatelliteStateChanged(boolean isEnabled);
 }
diff --git a/packages/Shell/AndroidManifest.xml b/packages/Shell/AndroidManifest.xml
index 05c5e5d..1919572 100644
--- a/packages/Shell/AndroidManifest.xml
+++ b/packages/Shell/AndroidManifest.xml
@@ -951,6 +951,9 @@
     <!-- Permission required for CTS test - CtsAppTestCases -->
     <uses-permission android:name="android.permission.KILL_UID" />
 
+    <!-- Permission required for CTS test - CtsTelephonyTestCases -->
+    <uses-permission android:name="android.permission.READ_BASIC_PHONE_STATE" />
+
     <application
         android:label="@string/app_label"
         android:theme="@android:style/Theme.DeviceDefault.DayNight"
diff --git a/services/core/java/com/android/server/TelephonyRegistry.java b/services/core/java/com/android/server/TelephonyRegistry.java
index 363807d..72a9a2d 100644
--- a/services/core/java/com/android/server/TelephonyRegistry.java
+++ b/services/core/java/com/android/server/TelephonyRegistry.java
@@ -102,6 +102,7 @@
 import com.android.internal.telephony.ICarrierPrivilegesCallback;
 import com.android.internal.telephony.IOnSubscriptionsChangedListener;
 import com.android.internal.telephony.IPhoneStateListener;
+import com.android.internal.telephony.ISatelliteStateChangeListener;
 import com.android.internal.telephony.ITelephonyRegistry;
 import com.android.internal.telephony.TelephonyPermissions;
 import com.android.internal.telephony.flags.Flags;
@@ -126,6 +127,7 @@
 import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.stream.Collectors;
 
 /**
@@ -164,6 +166,7 @@
         IOnSubscriptionsChangedListener onOpportunisticSubscriptionsChangedListenerCallback;
         ICarrierPrivilegesCallback carrierPrivilegesCallback;
         ICarrierConfigChangeListener carrierConfigChangeListener;
+        ISatelliteStateChangeListener satelliteStateChangeListener;
 
         int callerUid;
         int callerPid;
@@ -196,6 +199,10 @@
             return carrierConfigChangeListener != null;
         }
 
+        boolean matchSatelliteStateChangeListener() {
+            return satelliteStateChangeListener != null;
+        }
+
         boolean canReadCallLog() {
             try {
                 return TelephonyPermissions.checkReadCallLog(
@@ -215,6 +222,7 @@
                     + onOpportunisticSubscriptionsChangedListenerCallback
                     + " carrierPrivilegesCallback=" + carrierPrivilegesCallback
                     + " carrierConfigChangeListener=" + carrierConfigChangeListener
+                    + " satelliteStateChangeListener=" + satelliteStateChangeListener
                     + " subId=" + subId + " phoneId=" + phoneId + " events=" + eventList + "}";
         }
     }
@@ -433,6 +441,10 @@
 
     private List<IntArray> mCarrierRoamingNtnAvailableServices;
 
+    // Local cache to check if Satellite Modem is enabled
+    private AtomicBoolean mIsSatelliteEnabled;
+    private AtomicBoolean mWasSatelliteEnabledNotified;
+
     /**
      * Per-phone map of precise data connection state. The key of the map is the pair of transport
      * type and APN setting. This is the cache to prevent redundant callbacks to the listeners.
@@ -871,6 +883,9 @@
         mCarrierRoamingNtnMode = new boolean[numPhones];
         mCarrierRoamingNtnEligible = new boolean[numPhones];
         mCarrierRoamingNtnAvailableServices = new ArrayList<>();
+        mIsSatelliteEnabled = new AtomicBoolean();
+        mWasSatelliteEnabledNotified = new AtomicBoolean();
+
 
         for (int i = 0; i < numPhones; i++) {
             mCallState[i] =  TelephonyManager.CALL_STATE_IDLE;
@@ -3425,6 +3440,94 @@
     }
 
     @Override
+    public void addSatelliteStateChangeListener(@NonNull ISatelliteStateChangeListener listener,
+            @NonNull String pkg, @Nullable String featureId) {
+        final int callerUserId = UserHandle.getCallingUserId();
+        mAppOps.checkPackage(Binder.getCallingUid(), pkg);
+        enforceCallingOrSelfAtLeastReadBasicPhoneStatePermission(pkg, featureId,
+                "addSatelliteStateChangeListener");
+        if (VDBG) {
+            log("addSatelliteStateChangeListener pkg=" + pii(pkg)
+                    + " uid=" + Binder.getCallingUid()
+                    + " myUserId=" + UserHandle.myUserId() + " callerUerId" + callerUserId
+                    + " listener=" + listener + " listener.asBinder=" + listener.asBinder());
+        }
+
+        synchronized (mRecords) {
+            final IBinder b = listener.asBinder();
+            boolean doesLimitApply = doesLimitApplyForListeners(Binder.getCallingUid(),
+                    Process.myUid());
+            Record r = add(b, Binder.getCallingUid(), Binder.getCallingPid(), doesLimitApply);
+
+            if (r == null) {
+                loge("addSatelliteStateChangeListener: can not create Record instance!");
+                return;
+            }
+
+            r.context = mContext;
+            r.satelliteStateChangeListener = listener;
+            r.callingPackage = pkg;
+            r.callingFeatureId = featureId;
+            r.callerUid = Binder.getCallingUid();
+            r.callerPid = Binder.getCallingPid();
+            r.eventList = new ArraySet<>();
+            if (DBG) {
+                log("addSatelliteStateChangeListener:  Register r=" + r);
+            }
+
+            // Always notify registrants on registration if it has been notified before
+            if (mWasSatelliteEnabledNotified.get() && r.matchSatelliteStateChangeListener()) {
+                try {
+                    r.satelliteStateChangeListener.onSatelliteEnabledStateChanged(
+                            mIsSatelliteEnabled.get());
+                } catch (RemoteException e) {
+                    throw new RuntimeException(e);
+                }
+            }
+        }
+    }
+
+    @Override
+    public void removeSatelliteStateChangeListener(@NonNull ISatelliteStateChangeListener listener,
+            @NonNull String pkg) {
+        if (DBG) log("removeSatelliteStateChangeListener listener=" + listener + ", pkg=" + pkg);
+        mAppOps.checkPackage(Binder.getCallingUid(), pkg);
+        enforceCallingOrSelfAtLeastReadBasicPhoneStatePermission(pkg, null,
+                "removeSatelliteStateChangeListener");
+        remove(listener.asBinder());
+    }
+
+    @Override
+    public void notifySatelliteStateChanged(boolean isEnabled) {
+        if (!checkNotifyPermission("notifySatelliteStateChanged")) {
+            loge("notifySatelliteStateChanged: Caller has no notify permission!");
+            return;
+        }
+        if (VDBG) {
+            log("notifySatelliteStateChanged: isEnabled=" + isEnabled);
+        }
+
+        mWasSatelliteEnabledNotified.set(true);
+        mIsSatelliteEnabled.set(isEnabled);
+
+        synchronized (mRecords) {
+            mRemoveList.clear();
+            for (Record r : mRecords) {
+                // Listeners are "global", neither per-slot nor per-sub, so no idMatch check here
+                if (!r.matchSatelliteStateChangeListener()) {
+                    continue;
+                }
+                try {
+                    r.satelliteStateChangeListener.onSatelliteEnabledStateChanged(isEnabled);
+                } catch (RemoteException re) {
+                    mRemoveList.add(r.binder);
+                }
+            }
+            handleRemoveListLocked();
+        }
+    }
+
+    @Override
     public void notifyMediaQualityStatusChanged(int phoneId, int subId, MediaQualityStatus status) {
         if (!checkNotifyPermission("notifyMediaQualityStatusChanged()")) {
             return;
@@ -4622,4 +4725,32 @@
         if (packageNames.isEmpty() || Build.IS_DEBUGGABLE) return packageNames.toString();
         return "[***, size=" + packageNames.size() + "]";
     }
+
+    /**
+     * The method enforces the calling package at least has READ_BASIC_PHONE_STATE permission.
+     * That is, calling package either has READ_PRIVILEGED_PHONE_STATE, READ_PHONE_STATE or Carrier
+     * Privileges on ANY active subscription, or has READ_BASIC_PHONE_STATE permission.
+     */
+    private void enforceCallingOrSelfAtLeastReadBasicPhoneStatePermission(String pkgName,
+            String featureId, String message) {
+        // Check if calling app has READ_PHONE_STATE on ANY active subscription
+        boolean hasReadPhoneState = false;
+        SubscriptionManager sm = mContext.getSystemService(SubscriptionManager.class);
+        if (sm != null) {
+            for (int subId : sm.getActiveSubscriptionIdList()) {
+                if (TelephonyPermissions.checkCallingOrSelfReadPhoneStateNoThrow(mContext, subId,
+                        pkgName, featureId, message)) {
+                    hasReadPhoneState = true;
+                    break;
+                }
+            }
+        }
+
+        // If yes, pass. If not, then enforce READ_BASIC_PHONE_STATE permission
+        if (!hasReadPhoneState) {
+            mContext.enforceCallingOrSelfPermission(
+                    Manifest.permission.READ_BASIC_PHONE_STATE,
+                    message);
+        }
+    }
 }
diff --git a/telephony/java/android/telephony/satellite/SatelliteManager.java b/telephony/java/android/telephony/satellite/SatelliteManager.java
index e332d0f..be02232 100644
--- a/telephony/java/android/telephony/satellite/SatelliteManager.java
+++ b/telephony/java/android/telephony/satellite/SatelliteManager.java
@@ -26,6 +26,7 @@
 import android.annotation.RequiresFeature;
 import android.annotation.RequiresPermission;
 import android.annotation.SystemApi;
+import android.annotation.SystemService;
 import android.content.Context;
 import android.content.pm.PackageManager;
 import android.os.Binder;
@@ -39,6 +40,7 @@
 import android.telephony.TelephonyCallback;
 import android.telephony.TelephonyFrameworkInitializer;
 import android.telephony.TelephonyManager;
+import android.telephony.TelephonyRegistryManager;
 
 import com.android.internal.telephony.IIntegerConsumer;
 import com.android.internal.telephony.ITelephony;
@@ -61,13 +63,19 @@
 import java.util.stream.Collectors;
 
 /**
- * Manages satellite operations such as provisioning, pointing, messaging, location sharing, etc.
- * To get the object, call {@link Context#getSystemService(String)}.
+ * Manages satellite states such as monitoring enabled state and operations such as provisioning,
+ * pointing, messaging, location sharing, etc.
  *
- * @hide
+ * <p>To get the object, call {@link Context#getSystemService(String)} with
+ * {@link Context#SATELLITE_SERVICE}.
+ *
+ * <p>SatelliteManager is intended for use on devices with feature
+ * {@link PackageManager#FEATURE_TELEPHONY_SATELLITE}. On devices without the feature, the behavior
+ * is not reliable.
  */
+@SystemService(Context.SATELLITE_SERVICE)
+@FlaggedApi(Flags.FLAG_SATELLITE_STATE_CHANGE_LISTENER)
 @RequiresFeature(PackageManager.FEATURE_TELEPHONY_SATELLITE)
-@SystemApi
 public final class SatelliteManager {
     private static final String TAG = "SatelliteManager";
 
@@ -103,6 +111,8 @@
      */
     @Nullable private final Context mContext;
 
+    private TelephonyRegistryManager mTelephonyRegistryMgr;
+
     /**
      * Create an instance of the SatelliteManager.
      *
@@ -736,6 +746,65 @@
             "android.telephony.METADATA_SATELLITE_MANUAL_CONNECT_P2P_SUPPORT";
 
     /**
+     * Registers a {@link SatelliteStateChangeListener} to receive callbacks when the satellite
+     * state may have changed.
+     *
+     * <p>The callback method is immediately triggered with latest state on invoking this method if
+     * the state change has been notified before.
+     *
+     * @param executor The {@link Executor} where the {@code listener} will be invoked
+     * @param listener The listener to monitor the satellite state change
+     *
+     * @see SatelliteStateChangeListener
+     * @see TelephonyManager#hasCarrierPrivileges()
+     */
+    @FlaggedApi(Flags.FLAG_SATELLITE_STATE_CHANGE_LISTENER)
+    @RequiresPermission(anyOf = {android.Manifest.permission.READ_BASIC_PHONE_STATE,
+            android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE,
+            android.Manifest.permission.READ_PHONE_STATE,
+            "carrier privileges"})
+    public void registerStateChangeListener(@NonNull @CallbackExecutor Executor executor,
+            @NonNull SatelliteStateChangeListener listener) {
+        if (mContext == null) {
+            throw new IllegalStateException("Telephony service is null");
+        }
+
+        mTelephonyRegistryMgr = mContext.getSystemService(TelephonyRegistryManager.class);
+        if (mTelephonyRegistryMgr == null) {
+            throw new IllegalStateException("Telephony registry service is null");
+        }
+        mTelephonyRegistryMgr.addSatelliteStateChangeListener(executor, listener);
+    }
+
+    /**
+     * Unregisters the {@link SatelliteStateChangeListener} previously registered with
+     * {@link #registerStateChangeListener(Executor, SatelliteStateChangeListener)}.
+     *
+     * <p>It will be a no-op if the {@code listener} is not currently registered.
+     *
+     * @param listener The listener to unregister
+     *
+     * @see SatelliteStateChangeListener
+     * @see TelephonyManager#hasCarrierPrivileges()
+     */
+    @FlaggedApi(Flags.FLAG_SATELLITE_STATE_CHANGE_LISTENER)
+    @RequiresPermission(anyOf = {android.Manifest.permission.READ_BASIC_PHONE_STATE,
+            android.Manifest.permission.READ_PRIVILEGED_PHONE_STATE,
+            android.Manifest.permission.READ_PHONE_STATE,
+            "carrier privileges"})
+    public void unregisterStateChangeListener(@NonNull SatelliteStateChangeListener listener) {
+        if (mContext == null) {
+            throw new IllegalStateException("Telephony service is null");
+        }
+
+        mTelephonyRegistryMgr = mContext.getSystemService(TelephonyRegistryManager.class);
+        if (mTelephonyRegistryMgr == null) {
+            throw new IllegalStateException("Telephony registry service is null");
+        }
+        mTelephonyRegistryMgr.removeSatelliteStateChangeListener(listener);
+    }
+
+    /**
      * Request to enable or disable the satellite modem and demo mode.
      * If satellite modem and cellular modem cannot work concurrently,
      * then this will disable the cellular modem if satellite modem is enabled,
diff --git a/telephony/java/android/telephony/satellite/SatelliteStateChangeListener.java b/telephony/java/android/telephony/satellite/SatelliteStateChangeListener.java
new file mode 100644
index 0000000..3aa910d
--- /dev/null
+++ b/telephony/java/android/telephony/satellite/SatelliteStateChangeListener.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.telephony.satellite;
+
+import android.annotation.FlaggedApi;
+
+import com.android.internal.telephony.flags.Flags;
+
+import java.util.concurrent.Executor;
+
+/**
+ * A listener interface to monitor satellite state change events.
+ *
+ * <p>Call
+ * {@link SatelliteManager#registerStateChangeListener(Executor, SatelliteStateChangeListener)}
+ * to monitor. Call
+ * {@link SatelliteManager#unregisterStateChangeListener(SatelliteStateChangeListener)} to cancel.
+ *
+ * @see SatelliteManager#registerStateChangeListener(Executor, SatelliteStateChangeListener)
+ * @see SatelliteManager#unregisterStateChangeListener(SatelliteStateChangeListener)
+ */
+@FlaggedApi(Flags.FLAG_SATELLITE_STATE_CHANGE_LISTENER)
+public interface SatelliteStateChangeListener {
+    /**
+     * Called when satellite modem enabled state may have changed.
+     *
+     * <p>Note:there is no guarantee that this callback will only be invoked upon a change of state.
+     * In other word, in some cases, the callback may report with the same enabled states. It is the
+     * caller's responsibility to filter uninterested states.
+     *
+     * <p>Note:satellite enabled state is a device state that is NOT associated with subscription or
+     * SIM slot.
+     *
+     * @param isEnabled {@code true} means satellite modem is enabled.
+     */
+    void onEnabledStateChanged(boolean isEnabled);
+}