Addressing comments I originally made on Sandor's change.

MyTracks/res/drawable/left_arrow_chart_stateful.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+Copyright 2010 Google Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+<selector xmlns:android="http://schemas.android.com/apk/res/android"><!--
+
+  <item android:state_window_focused="false"
+        android:drawable="@drawable/left_arrow_chart" />
+
+  --><item android:state_pressed="true"
+        android:drawable="@drawable/left_arrow_chart_press" />
+
+  <item android:drawable="@drawable/left_arrow_chart" />
+
+</selector>

MyTracks/res/drawable/left_arrow_stats_stateful.xml

@@ -17,11 +17,11 @@ limitations under the License.
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
 
   <item android:state_window_focused="false"
-      android:drawable="@drawable/btn_arrow_left_default" />
+        android:drawable="@drawable/left_arrow_stats" />
 
   <item android:state_pressed="true"
-      android:drawable="@drawable/btn_arrow_left_press" />
+        android:drawable="@drawable/left_arrow_stats_press" />
 
-  <item android:drawable="@drawable/btn_arrow_left_default" />
+  <item android:drawable="@drawable/left_arrow_stats" />
 
 </selector>

MyTracks/res/drawable/left_arrow_track_stateful.xml

@@ -17,11 +17,11 @@ limitations under the License.
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
 
   <item android:state_window_focused="false"
-      android:drawable="@drawable/btn_arrow_right_default" />
+        android:drawable="@drawable/left_arrow_track" />
 
   <item android:state_pressed="true"
-      android:drawable="@drawable/btn_arrow_right_press" />
+        android:drawable="@drawable/left_arrow_track_press" />
 
-  <item android:drawable="@drawable/btn_arrow_right_default" />
+  <item android:drawable="@drawable/left_arrow_track" />
 
 </selector>

MyTracks/res/drawable/right_arrow_chart_stateful.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+Copyright 2010 Google Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+
+  <item android:state_window_focused="false"
+        android:drawable="@drawable/right_arrow_chart" />
+
+  <item android:state_pressed="true"
+        android:drawable="@drawable/right_arrow_chart_press" />
+
+  <item android:drawable="@drawable/right_arrow_chart" />
+
+</selector>

MyTracks/res/drawable/right_arrow_stats_stateful.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+Copyright 2010 Google Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+
+  <item android:state_window_focused="false"
+        android:drawable="@drawable/right_arrow_stats" />
+
+  <item android:state_pressed="true"
+        android:drawable="@drawable/right_arrow_stats_press" />
+
+  <item android:drawable="@drawable/right_arrow_stats" />
+
+</selector>

MyTracks/res/drawable/right_arrow_track_stateful.xml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+Copyright 2010 Google Inc.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+-->
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+
+  <item android:state_window_focused="false"
+        android:drawable="@drawable/right_arrow_track" />
+
+  <item android:state_pressed="true"
+        android:drawable="@drawable/right_arrow_track_press" />
+
+  <item android:drawable="@drawable/right_arrow_track" />
+
+</selector>

MyTracks/src/com/google/android/apps/mytracks/ChartActivity.java

@@ -177,15 +177,15 @@ public class ChartActivity extends Activity implements
                 cursor.getColumnIndexOrThrow(TrackPointsColumns._ID);
             ArrayList<double[]> data = new ArrayList<double[]>();
             // Need two locations so we can keep track of the last location.
-            Location[] locations = { new Location(""), new Location("")};
-            int i = 0;
+            Location location = new Location("");
             do {
               lastSeenLocationId = cursor.getLong(idColumnIdx);
-              providerUtils.fillLocation(cursor, locations[i]);
-              if (MyTracksUtils.isValidLocation(locations[i])) {
-                data.add(getDataPoint(locations[i], track));
+              providerUtils.fillLocation(cursor, location);
+              if (MyTracksUtils.isValidLocation(location)) {
+                double[] point = new double[3];
+                location = getDataPoint(location, track, point);
+                data.add(point);
               }
-              i = (i + 1) % 2;
             } while (cursor.moveToPrevious());
             cv.addDataPoints(data);
           }
@@ -465,11 +465,14 @@ public class ChartActivity extends Activity implements
    * data[1] = the elevation
    * data[2] = the speed
    *
-   * @param location a location
-   * @return the data point
+   * This must be called in order for each point.
+   *
+   * @param location the location to get data for (this method takes ownership of that location)
+   * @param track the track to get data from
+   * @param result the resulting point to fill out
+   * @return the previous location, now available for reuse
    */
-  public double[] getDataPoint(Location location, Track track) {
-    double[] result = new double[3];
+  private Location getDataPoint(Location location, Track track, double[] result) {
     switch (mode) {
       case BY_DISTANCE:
         result[0] = profileLength;
@@ -516,8 +519,16 @@ public class ChartActivity extends Activity implements
       // Format as hours per unit
       result[2] = (60.0 / result[2]);
     }
+
+    Location oldLastLocation = lastLocation;
     lastLocation = location;
-    return result;
+
+    if (oldLastLocation == null) {
+      // No previous location, but return a blank one for reuse
+      return new Location("");
+    }
+
+    return oldLastLocation;
   }
 
   /**
@@ -561,8 +572,7 @@ public class ChartActivity extends Activity implements
       final ArrayList<double[]> theData = new ArrayList<double[]>();
       int points = 0;
       // Need two locations so we can keep track of the last location.
-      Location[] locations = { new Location(""), new Location("")};
-      int i = 0;
+      Location location = new Location("");
       while (lastLocationRead < track.getStopId()) {
         cursor = providerUtils.getLocationsCursor(
             selectedTrackId, lastLocationRead, bufferSize, false);
@@ -574,16 +584,16 @@ public class ChartActivity extends Activity implements
                 cursor.getColumnIndexOrThrow(TrackPointsColumns._ID);
             while (cursor.moveToNext()) {
               points++;
-              providerUtils.fillLocation(cursor, locations[i]);
-              if (MyTracksUtils.isValidLocation(locations[i])) {
+              providerUtils.fillLocation(cursor, location);
+              if (MyTracksUtils.isValidLocation(location)) {
                 lastLocationRead = lastSeenLocationId =
                     cursor.getLong(idColumnIdx);
-                double[] point = getDataPoint(locations[i], track);
+                double[] point = new double[3];
+                location = getDataPoint(location, track, point);
                 if (points % chartSamplingFrequency == 0) {
                   theData.add(point);
                 }
               }
-              i = (i + 1) % 2;
             }
           } else {
             lastLocationRead += bufferSize;

MyTracks/src/com/google/android/apps/mytracks/MyTracks.java

@@ -76,7 +76,6 @@ import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.HashMap;
-import java.util.Random;
 
 import javax.xml.parsers.ParserConfigurationException;
 
@@ -213,40 +212,25 @@ public class MyTracks extends TabActivity implements OnTouchListener,
    * Tabs/View navigation:
    */
 
-  private static final int NUM_TABS = 3;
-  private int currentTab = 0;
-
   private NavControls navControls;
 
-  private final int icons[] =
-      { R.drawable.arrow_grey, R.drawable.menu_by_time,
-        R.drawable.menu_elevation };
+  /** Icons shown on the left for each tab. */
+  private final int leftIcons[] =
+      { R.drawable.left_arrow_chart_stateful,
+        R.drawable.left_arrow_track_stateful,
+        R.drawable.left_arrow_stats_stateful };
+  /** Icons shown on the right for each tab. */
+  private final int rightIcons[] =
+      { R.drawable.right_arrow_stats_stateful,
+        R.drawable.right_arrow_chart_stateful,
+        R.drawable.right_arrow_track_stateful };
 
-  private final Runnable nextActivity = new Runnable() {
+  private final Runnable changeTab = new Runnable() {
     public void run() {
-      currentTab = (currentTab + 1) % NUM_TABS;
-      navControls.setLeftIcon(icons[(currentTab + NUM_TABS - 1) % NUM_TABS]);
-      navControls.setRightIcon(icons[(currentTab + NUM_TABS + 1) % NUM_TABS]);
-      getTabHost().setCurrentTab(currentTab);
-      navControls.show();
+      getTabHost().setCurrentTab(navControls.getCurrentIcons());
     }
   };
 
-  private final Runnable prevActivity = new Runnable() {
-    public void run() {
-      currentTab--;
-      if (currentTab < 0) {
-        currentTab = NUM_TABS - 1;
-      }
-      navControls.setLeftIcon(icons[(currentTab + NUM_TABS - 1) % NUM_TABS]);
-      navControls.setRightIcon(icons[(currentTab + NUM_TABS + 1) % NUM_TABS]);
-      getTabHost().setCurrentTab(currentTab);
-      navControls.show();
-    }
-  };
-
-  private final Random random = new Random();
-
   public static MyTracks getInstance() {
     return instance;
   }
@@ -307,9 +291,7 @@ public class MyTracks extends TabActivity implements OnTouchListener,
     LayoutParams params =
         new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
     layout.setLayoutParams(params);
-    navControls = new NavControls(this, layout, prevActivity, nextActivity);
-    navControls.setLeftIcon(icons[NUM_TABS - 1]);
-    navControls.setRightIcon(icons[1]);
+    navControls = new NavControls(this, layout, leftIcons, rightIcons, changeTab);
     navControls.show();
     tabHost.addView(layout);
     layout.setOnTouchListener(this);
@@ -368,8 +350,6 @@ public class MyTracks extends TabActivity implements OnTouchListener,
     Log.d(MyTracksConstants.TAG, "MyTracks.onResume");
     super.onResume();
     tryBindTrackRecordingService();
-    navControls.setLeftIcon(icons[(currentTab + NUM_TABS - 1) % NUM_TABS]);
-    navControls.setRightIcon(icons[(currentTab + NUM_TABS + 1) % NUM_TABS]);
   }
 
   @Override

MyTracks/src/com/google/android/apps/mytracks/NavControls.java

@@ -15,13 +15,9 @@
  */
 package com.google.android.apps.mytracks;
 
-import com.google.android.maps.mytracks.R;
-
-import android.app.Activity;
 import android.content.Context;
 import android.graphics.drawable.Drawable;
 import android.os.Handler;
-import android.util.DisplayMetrics;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
@@ -30,7 +26,6 @@ import android.view.animation.Animation;
 import android.widget.ImageView;
 import android.widget.RelativeLayout;
 import android.widget.RelativeLayout.LayoutParams;
-import android.widget.TextView;
 
 /**
  * Creates previous and next arrows for a given activity.
@@ -53,31 +48,22 @@ public class NavControls {
 
   /**
    * A touchable image view.
+   * When touched it changes the navigation control icons accordingly.
    */
-  public class TouchLayout extends RelativeLayout {
-    private final ImageView arrow;
+  private class TouchLayout extends RelativeLayout implements Runnable {
+    private final boolean isLeft;
     private final ImageView icon;
 
-    public TouchLayout(Activity activity, boolean isLeft) {
-      super(activity);
-      arrow = new ImageView(activity);
-      arrow.setImageDrawable(activity.getResources().getDrawable(
-          isLeft ? R.drawable.btn_arrow_left : R.drawable.btn_arrow_right));
-      icon = new ImageView(activity);
+    public TouchLayout(Context context, boolean isLeft) {
+      super(context);
+      this.isLeft = isLeft;
+      this.icon = new ImageView(context);
       icon.setVisibility(View.GONE);
-      addView(arrow);
       addView(icon);
-      DisplayMetrics metrics = new DisplayMetrics();
-      activity.getWindowManager().getDefaultDisplay().getMetrics(metrics);
-      // TODO: This should be a smooth function not a step function.
-      if (metrics.heightPixels > 600) {
-        icon.setPadding((isLeft ? 25 : 15), 39, 15, 0);
-      } else {
-        icon.setPadding((isLeft ? 15 : 10), 27, 15, 0);
-      }
     }
 
-    public void setIcon(Drawable drawable) {
+    public void setIcon(int iconId) {
+      Drawable drawable = getContext().getResources().getDrawable(iconId);
       icon.setImageDrawable(drawable);
       icon.setVisibility(View.VISIBLE);
     }
@@ -87,18 +73,11 @@ public class NavControls {
       switch (event.getAction()) {
         case MotionEvent.ACTION_DOWN:
           setPressed(true);
-          hide();
-          if (this == prevImage) {
-            if (prevRunnable != null) {
-              handler.post(prevRunnable);
-              return true;
-            }
-          } else if (this == nextImage) {
-            if (nextRunnable != null) {
-              handler.post(nextRunnable);
-              return true;
-            }
-          }
+          shiftIcons(isLeft);
+
+          // Call the user back
+          handler.post(this);
+
           break;
         case MotionEvent.ACTION_UP:
           setPressed(false);
@@ -106,55 +85,69 @@ public class NavControls {
       }
       return super.onTouchEvent(event);
     }
+
+    @Override
+    public void run() {
+      touchRunnable.run();
+      setPressed(false);
+    }
   }
 
-  private final Context context;
-  private final Runnable prevRunnable;
-  private final Runnable nextRunnable;
   private final Handler handler = new Handler();
   private final Runnable dismissControls = new Runnable() {
     public void run() {
       hide();
     }
   };
+
   private final TouchLayout prevImage;
   private final TouchLayout nextImage;
+  private final int[] leftIcons;
+  private final int[] rightIcons;
+  private final Runnable touchRunnable;
 
   private boolean isVisible = false;
-  private boolean hasNext = true;
-  private boolean hasPrev = true;
+  private int currentIcons;
+
+  public NavControls(Context context, ViewGroup container,
+      int[] leftIcons, int[] rightIcons,
+      Runnable touchRunnable) {
+    this.leftIcons = leftIcons;
+    this.rightIcons = rightIcons;
+    this.touchRunnable = touchRunnable;
+
+    if (leftIcons.length != rightIcons.length || leftIcons.length < 1) {
+      throw new IllegalArgumentException("Invalid icons specified");
+    }
+    if (touchRunnable == null) {
+      throw new NullPointerException("Runnable cannot be null");
+    }
 
-  public NavControls(Activity activity, ViewGroup container,
-      Runnable prevRunnable, Runnable nextRunnable) {
-    this.context = activity;
-    this.prevRunnable = prevRunnable;
-    this.nextRunnable = nextRunnable;
     LayoutParams prevParams = new LayoutParams(
         LayoutParams.WRAP_CONTENT,
         LayoutParams.WRAP_CONTENT);
-    prevParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
-    prevParams.addRule(RelativeLayout.CENTER_VERTICAL);
-    prevImage = new TouchLayout(activity, true);
-    prevImage.setLayoutParams(prevParams);
-    prevImage.setVisibility(View.INVISIBLE);
-    container.addView(prevImage);
     LayoutParams nextParams = new LayoutParams(
         LayoutParams.WRAP_CONTENT,
         LayoutParams.WRAP_CONTENT);
+
+    prevParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
     nextParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
+    prevParams.addRule(RelativeLayout.CENTER_VERTICAL);
     nextParams.addRule(RelativeLayout.CENTER_VERTICAL);
-    nextImage = new TouchLayout(activity, false);
+
+    nextImage = new TouchLayout(context, false);
+    prevImage = new TouchLayout(context, true);
     nextImage.setLayoutParams(nextParams);
+    prevImage.setLayoutParams(prevParams);
     nextImage.setVisibility(View.INVISIBLE);
+    prevImage.setVisibility(View.INVISIBLE);
+
+    container.addView(prevImage);
     container.addView(nextImage);
-  }
 
-  public void setHasNext(boolean hasNext) {
-    this.hasNext = hasNext;
-  }
-
-  public void setHasPrev(boolean hasPrev) {
-    this.hasPrev = hasPrev;
+    prevImage.setIcon(leftIcons[0]);
+    nextImage.setIcon(rightIcons[0]);
+    this.currentIcons = 0;
   }
 
   private void keepVisible() {
@@ -166,20 +159,18 @@ public class NavControls {
 
   public void show() {
     if (!isVisible) {
-      if (prevRunnable != null && hasPrev) {
-        SHOW_PREV_ANIMATION.setDuration(500);
-        SHOW_PREV_ANIMATION.startNow();
-        prevImage.setPressed(false);
-        prevImage.setAnimation(SHOW_PREV_ANIMATION);
-        prevImage.setVisibility(View.VISIBLE);
-      }
-      if (nextRunnable != null && hasNext) {
-        SHOW_NEXT_ANIMATION.setDuration(500);
-        SHOW_NEXT_ANIMATION.startNow();
-        nextImage.setPressed(false);
-        nextImage.setAnimation(SHOW_NEXT_ANIMATION);
-        nextImage.setVisibility(View.VISIBLE);
-      }
+      SHOW_PREV_ANIMATION.setDuration(500);
+      SHOW_PREV_ANIMATION.startNow();
+      prevImage.setPressed(false);
+      prevImage.setAnimation(SHOW_PREV_ANIMATION);
+      prevImage.setVisibility(View.VISIBLE);
+
+      SHOW_NEXT_ANIMATION.setDuration(500);
+      SHOW_NEXT_ANIMATION.startNow();
+      nextImage.setPressed(false);
+      nextImage.setAnimation(SHOW_NEXT_ANIMATION);
+      nextImage.setVisibility(View.VISIBLE);
+
       isVisible = true;
       keepVisible();
     } else {
@@ -198,33 +189,25 @@ public class NavControls {
 
   public void hide() {
     isVisible = false;
-    if (prevRunnable != null) {
-      if (hasPrev) {
-        prevImage.setAnimation(HIDE_PREV_ANIMATION);
-        HIDE_PREV_ANIMATION.setDuration(500);
-        HIDE_PREV_ANIMATION.startNow();
-      } else {
-        prevImage.clearAnimation();
-      }
-      prevImage.setVisibility(View.INVISIBLE);
-    }
-    if (nextRunnable != null) {
-      if (hasNext) {
-        nextImage.setAnimation(HIDE_NEXT_ANIMATION);
-        HIDE_NEXT_ANIMATION.setDuration(500);
-        HIDE_NEXT_ANIMATION.startNow();
-      } else {
-        nextImage.clearAnimation();
-      }
-      nextImage.setVisibility(View.INVISIBLE);
-    }
+    prevImage.setAnimation(HIDE_PREV_ANIMATION);
+    HIDE_PREV_ANIMATION.setDuration(500);
+    HIDE_PREV_ANIMATION.startNow();
+    prevImage.setVisibility(View.INVISIBLE);
+
+    nextImage.setAnimation(HIDE_NEXT_ANIMATION);
+    HIDE_NEXT_ANIMATION.setDuration(500);
+    HIDE_NEXT_ANIMATION.startNow();
+    nextImage.setVisibility(View.INVISIBLE);
   }
 
-  public void setLeftIcon(int resourceId) {
-    prevImage.setIcon(context.getResources().getDrawable(resourceId));
+  public int getCurrentIcons() {
+    return currentIcons;
   }
 
-  public void setRightIcon(int resourceId) {
-    nextImage.setIcon(context.getResources().getDrawable(resourceId));
+  private void shiftIcons(boolean isLeft) {
+    // Increment or decrement by one, with wrap around
+    currentIcons = (currentIcons + leftIcons.length + (isLeft ? -1 : 1)) % leftIcons.length;
+    prevImage.setIcon(leftIcons[currentIcons]);
+    nextImage.setIcon(rightIcons[currentIcons]);
   }
 }

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

@@ -203,7 +203,9 @@ public interface MyTracksProviderUtils {
    *
    * @param track to load locations for
    * @param buffer an array of locations to fill
+   * @deprecated use {@link #fillTrackPoints} instead
    */
+  @Deprecated
   void getTrackPoints(Track track, TrackBuffer buffer);
 
   /**

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

@@ -175,6 +175,8 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
   
   @Override
   public void fillLocation(Cursor cursor, Location location) {
+    location.reset();
+
     int idxLatitude = cursor.getColumnIndexOrThrow(TrackPointsColumns.LATITUDE);
     int idxLongitude =
         cursor.getColumnIndexOrThrow(TrackPointsColumns.LONGITUDE);
@@ -865,7 +867,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
           cursor.getColumnIndexOrThrow(TrackPointsColumns._ID);
       do {
         if (reuseLocations) {
-          fillLocation(cursor, buffer.location(cursor.getLong(idColumnIdx)));
+          fillLocation(cursor, buffer.add(cursor.getLong(idColumnIdx)));
         } else {
           Location location = createLocation(cursor);
           if (location == null) {
@@ -874,7 +876,7 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
           buffer.add(location, cursor.getLong(idColumnIdx));
         }
       } while (cursor.moveToNext());
-      
+
       if (buffer.getLocationsLoaded() == 0) {
         Log.w(MyTracksProvider.TAG, "No locations read.");
         buffer.resetAt(startingPoint + buffer.getSize());

MyTracks/src/com/google/android/apps/mytracks/content/TrackBuffer.java

@@ -98,11 +98,11 @@ public class TrackBuffer {
   /**
    * Get a location from the end of the buffer.
    * This may reuse Location objects already allocated to the buffer.
-   * @param id The of the location to be added.
+   * @param locationId The of the location to be added.
    * @return The location object associated with the give id.
    */
-  public Location location(long id) {
-    lastLocationRead = Math.max(lastLocationRead, id);
+  public Location add(long locationId) {
+    lastLocationRead = Math.max(lastLocationRead, locationId);
     if (buffer[locationsLoaded] == null) {
       buffer[locationsLoaded] = new Location("");
     } else {