Feature request: https://github.com/erickok/transdroid/issues/670

app/src/main/java/org/transdroid/core/gui/TorrentsActivity.java

@@ -864,6 +864,11 @@ protected void sortBySize() {
         fragmentTorrents.sortBy(TorrentsSortBy.Size);
     }
 
+    @OptionsItem(R.id.action_sort_numTrackers)
+    protected void sortByNumberOfTrackers() {
+        fragmentTorrents.sortBy(TorrentsSortBy.NumberOfTrackers);
+    }
+
     /**
      * Redirect the newly entered list filter to the torrents fragment.
      *

app/src/main/java/org/transdroid/core/gui/TorrentsFragment.java

@@ -43,24 +43,40 @@
 import org.androidannotations.annotations.ViewById;
 import org.transdroid.R;
 import org.transdroid.core.app.settings.ApplicationSettings;
+import org.transdroid.core.app.settings.ServerSetting;
 import org.transdroid.core.app.settings.SystemSettings;
 import org.transdroid.core.gui.lists.TorrentsAdapter;
 import org.transdroid.core.gui.lists.TorrentsAdapter_;
+import org.transdroid.core.gui.log.Log;
 import org.transdroid.core.gui.navigation.Label;
 import org.transdroid.core.gui.navigation.NavigationFilter;
 import org.transdroid.core.gui.navigation.RefreshableActivity;
 import org.transdroid.core.gui.navigation.SelectionManagerMode;
 import org.transdroid.core.gui.navigation.SetLabelDialog;
 import org.transdroid.core.gui.navigation.SetLabelDialog.OnLabelPickedListener;
 import org.transdroid.daemon.Daemon;
+import org.transdroid.daemon.IDaemonAdapter;
 import org.transdroid.daemon.Torrent;
+import org.transdroid.daemon.TorrentDetails;
 import org.transdroid.daemon.TorrentsComparator;
 import org.transdroid.daemon.TorrentsSortBy;
+import org.transdroid.daemon.task.DaemonTaskResult;
+import org.transdroid.daemon.task.GetTorrentDetailsTask;
+import org.transdroid.daemon.task.GetTorrentDetailsTaskSuccessResult;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Iterator;
+import java.util.List;
 import java.util.Locale;
+import java.util.Map;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
 
 /**
  * Fragment that shows a list of torrents that are active on the server. It supports sorting and filtering and can show connection progress and
@@ -78,6 +94,8 @@ public class TorrentsFragment extends Fragment implements OnLabelPickedListener
     protected ApplicationSettings applicationSettings;
     @Bean
     protected SystemSettings systemSettings;
+    @Bean
+    protected Log log;
     @InstanceState
     protected ArrayList<Torrent> lastMultiSelectedTorrents;
     @InstanceState
@@ -112,6 +130,7 @@ public class TorrentsFragment extends Fragment implements OnLabelPickedListener
     protected TextView errorText;
     @ViewById
     protected ProgressBar loadingProgress;
+    private static final String LOG_NAME = "Transdroid daemon";
     private MultiChoiceModeListener onTorrentsSelected = new MultiChoiceModeListener() {
 
         private SelectionManagerMode selectionManagerMode;
@@ -270,7 +289,7 @@ public void updateTorrents(ArrayList<Torrent> newTorrents, ArrayList<Label> curr
             return;
         }
 
-        torrents = newTorrents;
+        torrents = updateTorrentsWithTrackers(newTorrents);
         this.currentLabels = currentLabels;
         applyAllFilters();
     }
@@ -498,4 +517,38 @@ private TorrentTasksExecutor getTasksExecutor() {
         return (TorrentTasksExecutor) getActivity();
     }
 
+    private ArrayList<Torrent> updateTorrentsWithTrackers(ArrayList<Torrent> torrents) {
+        ServerSetting lastUsed = applicationSettings.getLastUsedServer();
+        IDaemonAdapter currentConnection = lastUsed.getServerAdapter("", getActivity());
+        ExecutorService executor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
+        Map<Torrent, Future<?>> futureMap = new HashMap<>(); //using a map here in-case we want a list of failed torrents in the future
+
+        for(Torrent torrent: torrents) {
+            Future<?> future = executor.submit(() -> {
+                DaemonTaskResult result = GetTorrentDetailsTask.create(currentConnection, torrent).execute(new Log());
+
+                if (result instanceof GetTorrentDetailsTaskSuccessResult) {
+                    int numOfTrackers = ((GetTorrentDetailsTaskSuccessResult) result).getTorrentDetails().getTrackers().size();
+                    torrent.setNumberOfTrackers(numOfTrackers);
+                }
+            });
+            futureMap.put(torrent, future);
+        }
+
+        for (Map.Entry<Torrent, Future<?>> entry : futureMap.entrySet()) {
+            Torrent torrent = entry.getKey();
+            Future<?> future = entry.getValue();
+
+            try {
+                //wait 1 sec max to get result
+                future.get(1, TimeUnit.SECONDS);
+            } catch (Exception e) {
+                future.cancel(true);
+                log.d(LOG_NAME, "Unable to fetch number of trackers for: " + torrent.getName() + " -> " + e.getMessage());
+            }
+        }
+        executor.shutdown();
+        return torrents;
+    }
+
 }

app/src/main/java/org/transdroid/daemon/Torrent.java

@@ -63,7 +63,7 @@ public Torrent[] newArray(int size) {
     private String label;
     private boolean sequentialDownload;
     private boolean firstLastPieceDownload;
-
+    private int numberOfTrackers;
 
     private Torrent(Parcel in) {
         this.id = in.readLong();
@@ -283,6 +283,14 @@ public Daemon getDaemon() {
         return daemon;
     }
 
+    public int getNumberOfTrackers() {
+        return this.numberOfTrackers;
+    }
+
+    public void setNumberOfTrackers(int numberOfTrackers) {
+        this.numberOfTrackers = numberOfTrackers;
+    }
+
     /**
      * Returns the torrent-specific ID, which is the torrent's hash or (if not available) the long number
      *

app/src/main/java/org/transdroid/daemon/TorrentsComparator.java

@@ -76,6 +76,8 @@ public int compare(Torrent tor1, Torrent tor2) {
                     return Double.compare(tor1.getRatio(), tor2.getRatio());
                 case Size:
                     return Double.compare(tor1.getTotalSize(), (double) tor2.getTotalSize());
+                case NumberOfTrackers:
+                    return Integer.compare(tor1.getNumberOfTrackers(), tor2.getNumberOfTrackers());
                 default:
                     return alphanumComparator.compare(tor1.getName().toLowerCase(), tor2.getName().toLowerCase());
             }
@@ -101,6 +103,8 @@ public int compare(Torrent tor1, Torrent tor2) {
                     return -Double.compare(tor1.getRatio(), tor2.getRatio());
                 case Size:
                     return -Double.compare(tor1.getTotalSize(), (double) tor2.getTotalSize());
+                case NumberOfTrackers:
+                    return -Integer.compare(tor1.getNumberOfTrackers(), tor2.getNumberOfTrackers());
                 default:
                     return -alphanumComparator.compare(tor1.getName().toLowerCase(), tor2.getName().toLowerCase());
             }

app/src/main/java/org/transdroid/daemon/TorrentsSortBy.java

@@ -30,8 +30,8 @@ public enum TorrentsSortBy {
     Ratio(6),
     DownloadSpeed(7),
     Percent(8),
-    Size(9);
-
+    Size(9),
+    NumberOfTrackers(10);
     private static final Map<Integer, TorrentsSortBy> lookup = new HashMap<>();
 
     static {

app/src/main/res/menu/activity_torrents_secondary.xml

@@ -66,6 +66,9 @@
                 <item
                     android:id="@+id/action_sort_size"
                     android:title="@string/action_sort_size" />
+                <item
+                    android:id="@+id/action_sort_numTrackers"
+                    android:title="@string/action_sort_numTrackers" />
             </group>
         </menu>
     </item>

app/src/main/res/values/strings.xml

@@ -38,6 +38,7 @@
     <string name="action_sort_upspeed">Upload speed</string>
     <string name="action_sort_ratio">Ratio</string>
     <string name="action_sort_size">Size</string>
+    <string name="action_sort_numTrackers">Number of trackers</string>
     <string name="action_filter">Filter list</string>
     <string name="action_settings">Settings</string>
     <string name="action_help">Help</string>