Sort the updates, not their IDs

Also, use a comparator to sort the updates and stop using the
Comparable interface. There are different ways to sort updates,
so don't define one.

src/org/lineageos/updater/Update.java

@@ -15,7 +15,7 @@
  */
 package org.lineageos.updater;
 
-public class Update implements Comparable<Update> {
+public class Update {
 
     private String mName;
     private String mDownloadUrl;
@@ -83,9 +83,4 @@ public class Update implements Comparable<Update> {
     public void setDownloadUrl(String downloadUrl) {
         mDownloadUrl = downloadUrl;
     }
-
-    @Override
-    public int compareTo(Update u) {
-        return mTimestamp < u.mTimestamp ? -1 : mTimestamp > u.mTimestamp ? 1 : 0;
-    }
 }

src/org/lineageos/updater/UpdatesActivity.java

@@ -49,6 +49,7 @@ import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.List;
 
 public class UpdatesActivity extends AppCompatActivity {
@@ -188,8 +189,16 @@ public class UpdatesActivity extends AppCompatActivity {
         }
 
         List<String> updateIds = new ArrayList<>();
-        updateIds.addAll(controller.getIds());
-        Collections.sort(updateIds);
+        List<UpdateDownload> sortedUpdates = controller.getUpdates();
+        Collections.sort(sortedUpdates, new Comparator<UpdateDownload>() {
+            @Override
+            public int compare(UpdateDownload u1, UpdateDownload u2) {
+                return Long.compare(u2.getTimestamp(), u1.getTimestamp());
+            }
+        });
+        for (Update update : sortedUpdates) {
+            updateIds.add(update.getDownloadId());
+        }
         mAdapter.setData(updateIds);
         mAdapter.notifyDataSetChanged();
     }