Update Prevent Ringing summary when it turn off

Bug: 187145174
Test: manual & robotest
Change-Id: Ifc06a38ff65f084db2803c56b5a37224c5b9b810
diff --git a/src/com/android/settings/gestures/PreventRingingParentPreferenceController.java b/src/com/android/settings/gestures/PreventRingingParentPreferenceController.java
index ca1f1c7..b679438 100644
--- a/src/com/android/settings/gestures/PreventRingingParentPreferenceController.java
+++ b/src/com/android/settings/gestures/PreventRingingParentPreferenceController.java
@@ -92,8 +92,9 @@
             case VOLUME_HUSH_MUTE:
                 summary = mContext.getText(R.string.prevent_ringing_option_mute_summary);
                 break;
+            // VOLUME_HUSH_OFF
             default:
-                summary = null;
+                summary = mContext.getText(R.string.switch_off_text);
         }
         preference.setSummary(summary);
     }
diff --git a/tests/robotests/src/com/android/settings/gestures/PreventRingingParentPreferenceControllerTest.java b/tests/robotests/src/com/android/settings/gestures/PreventRingingParentPreferenceControllerTest.java
index 9e4877c..4844a1c 100644
--- a/tests/robotests/src/com/android/settings/gestures/PreventRingingParentPreferenceControllerTest.java
+++ b/tests/robotests/src/com/android/settings/gestures/PreventRingingParentPreferenceControllerTest.java
@@ -97,7 +97,8 @@
         Settings.Secure.putInt(mContext.getContentResolver(), VOLUME_HUSH_GESTURE,
                 VOLUME_HUSH_OFF);
         mController.updateState(mPreference);
-        assertThat(mPreference.getSummary()).isEqualTo(null);
+        assertThat(mPreference.getSummary()).isEqualTo(mContext.getResources().getText(
+                R.string.switch_off_text));
     }
 
     @Test