Update MyTracksProviderUtils api to make it clear

the valid values that can be used.

MyTracksLib/src/com/google/android/apps/mytracks/content/MyTracksProviderUtils.java

@@ -82,9 +82,9 @@ public interface MyTracksProviderUtils {
    * Gets a track cursor. The caller owns the returned cursor and is responsible
    * for closing it.
    * 
-   * @param selection the selection
-   * @param selectionArgs the selection arguments
-   * @param sortOrder the sort order
+   * @param selection the selection. Can be null
+   * @param selectionArgs the selection arguments. Can be null
+   * @param sortOrder the sort order. Can be null
    */
   public Cursor getTrackCursor(String selection, String[] selectionArgs, String sortOrder);
 
@@ -120,7 +120,7 @@ public interface MyTracksProviderUtils {
    * deletion. The generator is used to update the next statistics waypoint.
    * 
    * @param waypointId the waypoint id
-   * @param descriptionGenerator the description generator
+   * @param descriptionGenerator the description generator. Can be null for waypoint marker
    */
   public void deleteWaypoint(long waypointId, DescriptionGenerator descriptionGenerator);
 
@@ -160,10 +160,10 @@ public interface MyTracksProviderUtils {
    * Gets a waypoint cursor. The caller owns the returned cursor and is
    * responsible for closing it.
    * 
-   * @param selection the selection
-   * @param selectionArgs the selection arguments
-   * @param sortOrder the sort order
-   * @param maxWaypoints the maximum number of waypoints to return
+   * @param selection the selection. Can be null
+   * @param selectionArgs the selection arguments. Can be null
+   * @param sortOrder the sort order. Can be null
+   * @param maxWaypoints the maximum number of waypoints to return. -1 for no limit
    */
   public Cursor getWaypointCursor(
       String selection, String[] selectionArgs, String sortOrder, int maxWaypoints);
@@ -173,8 +173,8 @@ public interface MyTracksProviderUtils {
    * is responsible for closing it.
    * 
    * @param trackId the track id
-   * @param minWaypointId the minimum waypoint id
-   * @param maxWaypoints the maximum number of waypoints to return
+   * @param minWaypointId the minimum waypoint id. -1L to ignore
+   * @param maxWaypoints the maximum number of waypoints to return. -1 for no limit
    */
   public Cursor getWaypointCursor(long trackId, long minWaypointId, int maxWaypoints);
 
@@ -242,8 +242,8 @@ public interface MyTracksProviderUtils {
    * responsible for closing it.
    * 
    * @param trackId the track id
-   * @param startTrackPointId the starting track point id
-   * @param maxLocations maximum number of locations to return
+   * @param startTrackPointId the starting track point id. -1L to ignore
+   * @param maxLocations maximum number of locations to return. -1 for no limit
    * @param descending true to sort the result in descending order (latest
    *          location first)
    */
@@ -262,8 +262,7 @@ public interface MyTracksProviderUtils {
    * iteration, {@link LocationIterator#close()} must be called.
    * 
    * @param trackId the track id
-   * @param startTrackPointId the start track point id or -1L to start from the
-   *          first point
+   * @param startTrackPointId the starting track point id. -1L to ignore
    * @param descending true to sort the result in descending order (latest
    *          location first)
    * @param locationFactory the location factory

MyTracksLib/src/com/google/android/apps/mytracks/content/MyTracksProviderUtilsImpl.java

@@ -439,7 +439,8 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
   @Override
   public void deleteWaypoint(long waypointId, DescriptionGenerator descriptionGenerator) {
     final Waypoint waypoint = getWaypoint(waypointId);
-    if (waypoint != null && waypoint.getType() == Waypoint.TYPE_STATISTICS) {
+    if (waypoint != null && waypoint.getType() == Waypoint.TYPE_STATISTICS
+        && descriptionGenerator != null) {
       final Waypoint nextWaypoint = getNextStatisticsWaypointAfter(waypoint);
       if (nextWaypoint == null) {
         Log.d(TAG, "Unable to find the next statistics marker after deleting one.");
@@ -510,7 +511,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
       String selection = WaypointsColumns.TRACKID + "=?  AND " + WaypointsColumns.TYPE + "=?";
       int type = statistics ? Waypoint.TYPE_STATISTICS : Waypoint.TYPE_WAYPOINT;
       String[] selectionArgs = new String[] { Long.toString(trackId), Integer.toString(type) };
-      cursor = getWaypointCursor(projection, selection, selectionArgs, WaypointsColumns._ID, 0);
+      cursor = getWaypointCursor(projection, selection, selectionArgs, WaypointsColumns._ID, -1);
       if (cursor != null) {
         int count = cursor.getCount();
         /*
@@ -535,7 +536,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
     Cursor cursor = null;
     try {
       cursor = getWaypointCursor(null, WaypointsColumns._ID + "=?",
-          new String[] { Long.toString(waypointId) }, WaypointsColumns._ID, 0);
+          new String[] { Long.toString(waypointId) }, WaypointsColumns._ID, 1);
       if (cursor != null && cursor.moveToFirst()) {
         return createWaypoint(cursor);
       }
@@ -672,7 +673,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
     if (sortOrder == null) {
       sortOrder = WaypointsColumns._ID;
     }
-    if (maxWaypoints > 0) {
+    if (maxWaypoints >= 0) {
       sortOrder += " LIMIT " + maxWaypoints;
     }
     return contentResolver.query(
@@ -789,7 +790,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
     if (descending) {
       sortOrder += " DESC";
     }
-    if (maxLocations > 0) {
+    if (maxLocations >= 0) {
       sortOrder += " LIMIT " + maxLocations;
     }
     return getTrackPointCursor(null, selection, selectionArgs, sortOrder);