Workaround for NullPointerException on preference.getKey() for a Preference, which doesn't have a key: I simply added keys

Author: yvolk

app/calendar-widget/src/main/res/xml/preferences_feedback.xml

@@ -1,14 +1,18 @@
 <PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
     <Preference
+        android:key="feedbackGithub"
         android:summary="@string/feedback_github_desc"
-        android:title="@string/feedback_github_title">
+        android:title="@string/feedback_github_title"
+        android:persistent="false">
         <intent
             android:action="android.intent.action.VIEW"
             android:data="https://github.com/plusonelabs/calendar-widget" />
     </Preference>
     <Preference
+        android:key="feedbackPlayStore"
         android:summary="@string/feedback_play_store_desc"
-        android:title="@string/feedback_play_store_title">
+        android:title="@string/feedback_play_store_title"
+        android:persistent="false">
         <intent
             android:action="android.intent.action.VIEW"
             android:data="https://play.google.com/store/apps/details?id=com.plusonelabs.calendar" />