Add null checks in CallFeaturesSettings

Bug: 17939776
Change-Id: Ib02d0c4dd88cf81d60b1cbdaa7b2869e9165bdc8
diff --git a/src/com/android/phone/CallFeaturesSetting.java b/src/com/android/phone/CallFeaturesSetting.java
index b85cb7e..c38df5c 100644
--- a/src/com/android/phone/CallFeaturesSetting.java
+++ b/src/com/android/phone/CallFeaturesSetting.java
@@ -485,7 +485,10 @@
             mAudioManager.setParameter(HAC_KEY, hac != 0 ? HAC_VAL_ON : HAC_VAL_OFF);
             return true;
         } else if (preference == mVoicemailSettings) {
-            mVoicemailSettings.getDialog().getActionBar().setDisplayHomeAsUpEnabled(false);
+            final Dialog dialog = mVoicemailSettings.getDialog();
+            if (dialog != null) {
+                dialog.getActionBar().setDisplayHomeAsUpEnabled(false);
+            }
             if (DBG) log("onPreferenceTreeClick: Voicemail Settings Preference is clicked.");
             if (preference.getIntent() != null) {
                 if (DBG) {
@@ -511,7 +514,10 @@
                 return false;
             }
         } else if (preference == mVoicemailSettingsScreen) {
-            mVoicemailSettingsScreen.getDialog().getActionBar().setDisplayHomeAsUpEnabled(false);
+            final Dialog dialog = mVoicemailSettingsScreen.getDialog();
+            if (dialog != null) {
+                dialog.getActionBar().setDisplayHomeAsUpEnabled(false);
+            }
             return false;
         }
         return false;