Submit my changes before merging.

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

@@ -176,12 +176,16 @@ public class ChartActivity extends Activity implements
             final int idColumnIdx =
                 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;
             do {
               lastSeenLocationId = cursor.getLong(idColumnIdx);
-              Location location = providerUtils.createLocation(cursor);
-              if (location != null && MyTracksUtils.isValidLocation(location)) {
-                data.add(getDataPoint(location, track));
+              providerUtils.fillLocation(cursor, locations[i]);
+              if (MyTracksUtils.isValidLocation(locations[i])) {
+                data.add(getDataPoint(locations[i], track));
               }
+              i = (i + 1) % 2;
             } while (cursor.moveToPrevious());
             cv.addDataPoints(data);
           }
@@ -556,6 +560,9 @@ public class ChartActivity extends Activity implements
     try {
       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;
       while (lastLocationRead < track.getStopId()) {
         cursor = providerUtils.getLocationsCursor(
             selectedTrackId, lastLocationRead, bufferSize, false);
@@ -567,15 +574,16 @@ public class ChartActivity extends Activity implements
                 cursor.getColumnIndexOrThrow(TrackPointsColumns._ID);
             while (cursor.moveToNext()) {
               points++;
-              Location location = providerUtils.createLocation(cursor);
-              if (MyTracksUtils.isValidLocation(location)) {
+              providerUtils.fillLocation(cursor, locations[i]);
+              if (MyTracksUtils.isValidLocation(locations[i])) {
                 lastLocationRead = lastSeenLocationId =
                     cursor.getLong(idColumnIdx);
-                double[] point = getDataPoint(location, track);
+                double[] point = getDataPoint(locations[i], track);
                 if (points % chartSamplingFrequency == 0) {
                   theData.add(point);
                 }
               }
+              i = (i + 1) % 2;
             }
           } else {
             lastLocationRead += bufferSize;

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

@@ -1002,6 +1002,7 @@ public class MyTracksMap extends MapActivity
     int bufferSize = 1024;
     int points = 0;
     long tailLocationId = selectedTrack.getStopId() - 10;
+    Location location;
     while (lastSeenLocationId < (selectedTrack.getStopId() + 10)) {
       cursor = providerUtils.getLocationsCursor(
           selectedTrack.getId(), lastSeenLocationId + 1, bufferSize, false);
@@ -1010,7 +1011,7 @@ public class MyTracksMap extends MapActivity
             TrackPointsColumns._ID);
         do {
           points++;
-          Location location = providerUtils.createLocation(cursor);
+          location = providerUtils.createLocation(cursor);
           lastSeenLocationId = cursor.getLong(idColumnIdx);
           // Include a point if it fits one of the following criteria:
           // - Has the mod for the sampling frequency.
@@ -1021,7 +1022,7 @@ public class MyTracksMap extends MapActivity
               points % samplingFrequency == 0 ||
               points == 0 ||
               lastSeenLocationId > tailLocationId) {
-            mapOverlay.addLocation(location);
+            mapOverlay.addLocation(new Location(location));
           }
         } while (cursor.moveToNext());
       } else {

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

@@ -17,9 +17,11 @@ 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;
@@ -28,6 +30,7 @@ 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.
@@ -55,16 +58,23 @@ public class NavControls {
     private final ImageView arrow;
     private final ImageView icon;
 
-    public TouchLayout(Context context, boolean isLeft) {
-      super(context);
-      arrow = new ImageView(context);
-      arrow.setImageDrawable(context.getResources().getDrawable(
+    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(context);
+      icon = new ImageView(activity);
       icon.setVisibility(View.GONE);
       addView(arrow);
       addView(icon);
-      icon.setPadding((isLeft ? 15 : 10), 27, 15, 0);
+      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) {
@@ -114,9 +124,9 @@ public class NavControls {
   private boolean hasNext = true;
   private boolean hasPrev = true;
 
-  public NavControls(Context context, ViewGroup container,
+  public NavControls(Activity activity, ViewGroup container,
       Runnable prevRunnable, Runnable nextRunnable) {
-    this.context = context;
+    this.context = activity;
     this.prevRunnable = prevRunnable;
     this.nextRunnable = nextRunnable;
     LayoutParams prevParams = new LayoutParams(
@@ -124,7 +134,7 @@ public class NavControls {
         LayoutParams.WRAP_CONTENT);
     prevParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
     prevParams.addRule(RelativeLayout.CENTER_VERTICAL);
-    prevImage = new TouchLayout(context, true);
+    prevImage = new TouchLayout(activity, true);
     prevImage.setLayoutParams(prevParams);
     prevImage.setVisibility(View.INVISIBLE);
     container.addView(prevImage);
@@ -133,7 +143,7 @@ public class NavControls {
         LayoutParams.WRAP_CONTENT);
     nextParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
     nextParams.addRule(RelativeLayout.CENTER_VERTICAL);
-    nextImage = new TouchLayout(context, false);
+    nextImage = new TouchLayout(activity, false);
     nextImage.setLayoutParams(nextParams);
     nextImage.setVisibility(View.INVISIBLE);
     container.addView(nextImage);

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

@@ -206,6 +206,19 @@ public interface MyTracksProviderUtils {
    */
   void getTrackPoints(Track track, TrackBuffer buffer);
 
+  /**
+   * Fetches some number of locations for the given track.
+   *
+   * This is designed to be used to stream through large tracks without loading
+   * all points into memory.
+   * This method will reuse the Location objects in the buffer.  If you need a
+   * Location object copy the object.
+   *
+   * @param track to load locations for
+   * @param buffer an array of locations to fill
+   */
+  void fillTrackPoints(Track track, TrackBuffer buffer);
+
   /**
    * Creates a cursor over the tracks provider with a given selection.
    * Caller gets to own the returned cursor. Don't forget to close it.
@@ -293,7 +306,15 @@ public interface MyTracksProviderUtils {
    * @return a new location object
    */
   Location createLocation(Cursor cursor);
-
+  
+  /**
+   * Fill a location object with values from a given cursor.
+   * 
+   * @param cursor a cursor pointing at a db or provider with locations
+   * @param location a location object to be overwritten
+   */
+  void fillLocation(Cursor cursor, Location location);
+  
   /**
    * Creates a waypoint object from a given cursor.
    *

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

@@ -168,6 +168,13 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public Location createLocation(Cursor cursor) {
+    Location location = new Location("");
+    fillLocation(cursor, location);
+    return location;
+  }
+  
+  @Override
+  public void fillLocation(Cursor cursor, Location location) {
     int idxLatitude = cursor.getColumnIndexOrThrow(TrackPointsColumns.LATITUDE);
     int idxLongitude =
         cursor.getColumnIndexOrThrow(TrackPointsColumns.LONGITUDE);
@@ -177,7 +184,6 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
     int idxAccuracy = cursor.getColumnIndexOrThrow(TrackPointsColumns.ACCURACY);
     int idxSpeed = cursor.getColumnIndexOrThrow(TrackPointsColumns.SPEED);
 
-    Location location = new Location("");
     if (!cursor.isNull(idxLatitude)) {
       location.setLatitude(1. * cursor.getInt(idxLatitude) / 1E6);
     }
@@ -199,7 +205,6 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
     if (!cursor.isNull(idxAccuracy)) {
       location.setAccuracy(cursor.getFloat(idxAccuracy));
     }
-    return location;
   }
 
   @Override
@@ -822,6 +827,16 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
 
   @Override
   public void getTrackPoints(Track track, TrackBuffer buffer) {
+    getTrackPoints(track, buffer, false);
+  }
+  
+  @Override
+  public void fillTrackPoints(Track track, TrackBuffer buffer) {
+    getTrackPoints(track, buffer, true);
+  }
+
+  public void getTrackPoints(Track track, TrackBuffer buffer,
+      boolean reuseLocations) {
     long startingPoint = buffer.getLastLocationRead() == 0 ? track.getStartId()
         : buffer.getLastLocationRead();
     buffer.reset();
@@ -849,11 +864,15 @@ public class MyTracksProviderUtilsImpl implements MyTracksProviderUtils {
       final int idColumnIdx =
           cursor.getColumnIndexOrThrow(TrackPointsColumns._ID);
       do {
-        Location location = createLocation(cursor);
-        if (location == null) {
-          continue;
+        if (reuseLocations) {
+          fillLocation(cursor, buffer.location(cursor.getLong(idColumnIdx)));
+        } else {
+          Location location = createLocation(cursor);
+          if (location == null) {
+            continue;
+          }
+          buffer.add(location, cursor.getLong(idColumnIdx));
         }
-        buffer.add(location, cursor.getLong(idColumnIdx));
       } while (cursor.moveToNext());
       
       if (buffer.getLocationsLoaded() == 0) {

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

@@ -94,6 +94,22 @@ public class TrackBuffer {
     buffer[locationsLoaded++] = location;
     lastLocationRead = Math.max(lastLocationRead, id);
   }
+  
+  /**
+   * 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.
+   * @return The location object associated with the give id.
+   */
+  public Location location(long id) {
+    lastLocationRead = Math.max(lastLocationRead, id);
+    if (buffer[locationsLoaded] == null) {
+      buffer[locationsLoaded] = new Location("");
+    } else {
+      buffer[locationsLoaded].reset();
+    }
+    return buffer[locationsLoaded++];
+  }
 
   /**
    * @return The id of the last location loaded into the buffer

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

@@ -264,7 +264,7 @@ public class TrackWriter {
     while (buffer.getLastLocationRead() < track.getStopId()) {
       Log.d(MyTracksConstants.TAG,
           "Reading track points starting at: " + buffer.getLastLocationRead());
-      providerUtils.getTrackPoints(track, buffer);
+      providerUtils.fillTrackPoints(track, buffer);
       if (!wroteFirst) {
         Location first = buffer.findStartLocation();
         writer.writeBeginTrack(first);