#2966 RxJava2 null - explicit mark underlying Rx sources as NonNull

to be on the safe side, for cases that the consuming observers
already assumes the result is not null.

Rx observer : underlying sources marked as NonNull
OnlineFeedViewActivity.listener member : DBReader.getFeedList
StatisticsActivity.loadStatistics : DBReader.getStatistics
CustomMRControllerDialog.updateViews : CustomMRControllerDialog.fetchArt
CompletedDownloadsFragment.loadItems : DBReader.getDownloadedItems
DownloadLogFragment.loadItems : DBReader.getDownloadedItems
ItemDescriptionFragment.onViewCreated : .loadData, Timeline.processShownotes
SubscriptionFragment.loadSubscriptions : DBReader.getNavDrawerData
SubscriptionFragment.onContextItemSelected (x2) : DBWriter.markFeedSeen, DBWriter.markFeedRead
PreferenceController.export : ExportWorker.output member

3 files changed, 12 insertions, 2 deletions

diff --git a/core/src/main/java/de/danoeh/antennapod/core/storage/DBReader.java b/core/src/main/java/de/danoeh/antennapod/core/storage/DBReader.java
index 63227e550..6c619fa31 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/storage/DBReader.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/storage/DBReader.java
@@ -1,6 +1,7 @@
 package de.danoeh.antennapod.core.storage;
 
 import android.database.Cursor;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.util.ArrayMap;
 import android.text.TextUtils;
@@ -58,6 +59,7 @@ public final class DBReader {
      * of the returned list does NOT have its list of FeedItems yet. The FeedItem-list
      * can be loaded separately with {@link #getFeedItemList(Feed)}.
      */
+    @NonNull
     public static List<Feed> getFeedList() {
         Log.d(TAG, "Extracting Feedlist");
 
@@ -70,6 +72,7 @@ public final class DBReader {
         }
     }
 
+    @NonNull
     private static List<Feed> getFeedList(PodDBAdapter adapter) {
         Cursor cursor = null;
         try {
@@ -324,6 +327,7 @@ public final class DBReader {
      *
      * @return A list of FeedItems whose episdoe has been downloaded.
      */
+    @NonNull
     public static List<FeedItem> getDownloadedItems() {
         Log.d(TAG, "getDownloadedItems() called");
 
@@ -859,6 +863,7 @@ public final class DBReader {
      *                       countAll calculation time
      * @return The StatisticsInfo object
      */
+    @NonNull
     public static StatisticsData getStatistics(boolean sortByCountAll) {
         PodDBAdapter adapter = PodDBAdapter.getInstance();
         adapter.open();
@@ -1025,6 +1030,7 @@ public final class DBReader {
      * the list of subscriptions, the number of items in the queue and the number of unread
      * items.
      */
+    @NonNull
     public static NavDrawerData getNavDrawerData() {
         Log.d(TAG, "getNavDrawerData() called with: " + "");
         PodDBAdapter adapter = PodDBAdapter.getInstance();
diff --git a/core/src/main/java/de/danoeh/antennapod/core/storage/DBWriter.java b/core/src/main/java/de/danoeh/antennapod/core/storage/DBWriter.java
index ad20bfa0a..45dac4c53 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/storage/DBWriter.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/storage/DBWriter.java
@@ -5,6 +5,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.preference.PreferenceManager;
+import android.support.annotation.NonNull;
 import android.util.Log;
 
 import org.shredzone.flattr4j.model.Flattr;
@@ -633,11 +634,13 @@ public class DBWriter {
      *                           FeedItem.NEW, FeedItem.UNPLAYED
      * @param resetMediaPosition true if this method should also reset the position of the FeedItem's FeedMedia object.
      */
+    @NonNull
     public static Future<?> markItemPlayed(FeedItem item, int played, boolean resetMediaPosition) {
         long mediaId = (item.hasMedia()) ? item.getMedia().getId() : 0;
         return markItemPlayed(item.getId(), played, mediaId, resetMediaPosition);
     }
 
+    @NonNull
     private static Future<?> markItemPlayed(final long itemId,
                                             final int played,
                                             final long mediaId,
diff --git a/core/src/main/java/de/danoeh/antennapod/core/util/playback/Timeline.java b/core/src/main/java/de/danoeh/antennapod/core/util/playback/Timeline.java
index 56550bb06..75229b9cf 100644
--- a/core/src/main/java/de/danoeh/antennapod/core/util/playback/Timeline.java
+++ b/core/src/main/java/de/danoeh/antennapod/core/util/playback/Timeline.java
@@ -83,6 +83,7 @@ public class Timeline {
      * @param addTimecodes True if this method should add timecode links
      * @return The processed HTML string.
      */
+    @NonNull
     public String processShownotes(final boolean addTimecodes) {
         final Playable playable = (shownotesProvider instanceof Playable) ? (Playable) shownotesProvider : null;
 
@@ -92,8 +93,8 @@ public class Timeline {
         try {
             shownotes = shownotesProvider.loadShownotes().call();
         } catch (Exception e) {
-            e.printStackTrace();
-            return null;
+            Log.e(TAG, "processShownotes() - encounters exceptions unexpectedly in load, treat as if no shownotes.", e);
+            shownotes = "";
         }
 
         if (TextUtils.isEmpty(shownotes)) {