Add transparent background to record image button on the empty

track list view.

MyTracks/res/layout/track_list.xml

@@ -34,6 +34,7 @@ limitations under the License.
       style="@style/ListEmptyTextView" >
     </TextView>
     <ImageButton
+      android:background="@color/transparent"
       android:contentDescription="@string/menu_record_track"
       android:id="@+id/track_list_record_button"
       android:layout_height="wrap_content"

MyTracks/res/values/colors.xml

@@ -19,46 +19,45 @@ limitations under the License.
   <color name="blue">#FF0000FF</color>
   <color name="gray">#FFAAAAAA</color>
   <color name="red">#FFFF0000</color>
+  <color name="transparent">#00000000</color>
   <color name="white">#FFFFFFFF</color>
 
   <!-- holo_orange_dark -->
   <color name="warning_background">#FFFF8800</color>
-  
-  <!-- Chart colors by series. -->
-  <!-- Green and a transparent green -->
+
+  <!-- elevation chart colors, green and transparent green -->
   <color name="elevation_border">#FF339933</color>
   <color name="elevation_fill">#40B3CFB3</color>
 
-  <!-- Blue and a transparent blue -->
+  <!-- speed chart colors, blue and transparent blue -->
   <color name="speed_border">#FF0066FF</color>
   <color name="speed_fill">#40C8E0FF</color>
 
-  <!-- Blue and a transparent blue -->
+  <!-- pace chart colors, blue and transparent blue -->
   <color name="pace_border">#FF0066FF</color>
   <color name="pace_fill">#40C8E0FF</color>
-  
-  <!-- Red and a transparent red -->
-  <color name="heartrate_border">#FFCC3300</color>
-  <color name="heartrate_fill">#40E88A70</color>
 
-  <!-- Pink and a transparent pink -->
+  <!-- heart rate chart colors, red and transparent red -->
+  <color name="heart_rate_border">#FFCC3300</color>
+  <color name="heart_rate_fill">#40E88A70</color>
+
+  <!-- cadence chart colors, pink and transparent pink -->
   <color name="cadence_border">#FFF128F3</color>
   <color name="cadence_fill">#40F128F3</color>
 
-  <!-- Purple and a transparent purple -->
+  <!-- power chart colors, purple and transparent purple -->
   <color name="power_border">#FF401465</color>
   <color name="power_fill">#40401465</color>
 
-  <!-- AppWidget colors -->
+  <!-- app widget horizontal line -->
   <color name="appwidget_hr">#99999999</color>
-  
-  <!-- Colors for dynamic track drawing --> 
-  <!-- Green -->
+
+  <!-- dynamic track slow path, green -->
   <color name="slow_path">#F774DF00</color>
-  
-  <!-- Blue -->
+
+  <!-- dynamic track normal path, blue -->
   <color name="normal_path">#F75858FA</color>
-  
-  <!-- Red -->
+
+  <!-- dynamic track fast path, red -->
   <color name="fast_path">#F7DF0101</color>
-</resources>
+</resources>

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

@@ -160,8 +160,8 @@ public class ChartView extends View {
         new int[] {25, 50 },
         R.string.description_sensor_heart_rate,
         R.string.description_sensor_heart_rate,
-        R.color.heartrate_fill,
-        R.color.heartrate_border);
+        R.color.heart_rate_fill,
+        R.color.heart_rate_border);
     series[CADENCE_SERIES] = new ChartValueSeries(context,
         0,
         Integer.MAX_VALUE,