commit 660e7164c78358523abb46337f17881d299b59cb
author Jeremy Goldman <goldmanj@google.com> Mon Apr 19 16:53:07 2021 +0800
committer Jeremy Goldman <goldmanj@google.com> Tue Apr 20 11:33:17 2021 +0800
tree 8f5f7d7bda76a8b3331eac7d2f311f487224f542
parent 6de2953232bd8035cbc5db06e6743abca64499b3

Check if the SubscriptionsChangeListener has been started before stop

calling mContext.unregisterReceiver on an unregistered broadcast
receiver will result in an exception. To make the
SubscriptionsChangeListener safe from this kind of error, add a check to
see whether start has been called before implementing stop's
functionality.

Bug: 184662284
Bug: 184521296
Test: atest -c SettingsUnitTests
Change-Id: Ic13911ee7573666f5d42ab4612c025968984ba47

src/com/android/settings/network/SubscriptionsChangeListener.java

diff --git a/src/com/android/settings/network/SubscriptionsChangeListener.java b/src/com/android/settings/network/SubscriptionsChangeListener.java
index 192ee53..e13f85c 100644
--- a/src/com/android/settings/network/SubscriptionsChangeListener.java
+++ b/src/com/android/settings/network/SubscriptionsChangeListener.java
@@ -27,12 +27,15 @@
 import android.provider.Settings;
 import android.telephony.SubscriptionManager;
 import android.telephony.SubscriptionManager.OnSubscriptionsChangedListener;
+import android.util.Log;
 
 import com.android.internal.telephony.TelephonyIntents;
 
 /** Helper class for listening to changes in availability of telephony subscriptions */
 public class SubscriptionsChangeListener extends ContentObserver {
 
+    private static final String TAG = "SubscriptionsChangeListener";
+
     public interface SubscriptionsChangeListenerClient {
         void onAirplaneModeChanged(boolean airplaneModeEnabled);
         void onSubscriptionsChanged();
@@ -44,6 +47,7 @@
     private OnSubscriptionsChangedListener mSubscriptionsChangedListener;
     private Uri mAirplaneModeSettingUri;
     private BroadcastReceiver mBroadcastReceiver;
+    private boolean mRunning = false;
 
     public SubscriptionsChangeListener(Context context, SubscriptionsChangeListenerClient client) {
         super(new Handler(Looper.getMainLooper()));
@@ -75,12 +79,19 @@
         final IntentFilter radioTechnologyChangedFilter = new IntentFilter(
                 TelephonyIntents.ACTION_RADIO_TECHNOLOGY_CHANGED);
         mContext.registerReceiver(mBroadcastReceiver, radioTechnologyChangedFilter);
+        mRunning = true;
     }
 
     public void stop() {
-        mSubscriptionManager.removeOnSubscriptionsChangedListener(mSubscriptionsChangedListener);
-        mContext.getContentResolver().unregisterContentObserver(this);
-        mContext.unregisterReceiver(mBroadcastReceiver);
+        if (mRunning) {
+            mSubscriptionManager.removeOnSubscriptionsChangedListener(
+                    mSubscriptionsChangedListener);
+            mContext.getContentResolver().unregisterContentObserver(this);
+            mContext.unregisterReceiver(mBroadcastReceiver);
+            mRunning = false;
+        } else {
+            Log.d(TAG, "Stop has been called without associated Start.");
+        }
     }
 
     public boolean isAirplaneModeOn() {