* Added display_settings_screen_key to keys.xml and put it to use in

CheckUnits and SettingsActivity classes for use with intents.

* In SettingsActivity split onCreate() code into initActivityCommons() and
  initActivitySpecifics() methods for easier maintaining of code required
  for all screens and code require for only some screens.

MyTracks/res/values/keys.xml

@@ -53,4 +53,5 @@ limitations under the License.
   <string name="reset_key">resetToDefaults</string>
   <string name="sensor_options_key">sensorOptions</string>
   <string name="ant_options_key">antOptions</string>
+  <string name="display_settings_screen_key">displaySettingsScreen</string>
 </resources>

MyTracks/res/xml/preferences.xml

@@ -19,7 +19,7 @@ limitations under the License.
 
   <!-- Display settings -->
   <PreferenceScreen android:title="@string/settings_display"
-                    android:key="@string/settings_display">
+                    android:key="@string/display_settings_screen_key">
     <CheckBoxPreference
         android:key="@string/metric_units_key"
         android:title="@string/settings_metric_units"

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

@@ -81,7 +81,7 @@ class CheckUnits {
     recordCheckPerformed(preferences);
     Intent startIntent = new Intent(context, SettingsActivity.class);
     startIntent.putExtra(context.getString(R.string.open_settings_screen), 
-                         context.getString(R.string.settings_display));
+                         context.getString(R.string.display_settings_screen_key));
     context.startActivity(startIntent);
   }
 

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

@@ -50,7 +50,11 @@ import java.util.Set;
 
 /**
  * An activity that let's the user see and edit the settings.
- *
+ * 
+ * This activity has two entry points, "root" and "display" preference screen.
+ * If bundle.getString("open_settings_screen") is set to "display_settings_screen_key", then
+ * the "display" preference screen is shown, otherwise, the "root" display preference is shown.
+ * 
  * @author Leif Hendrik Wilden
  * @author Rodrigo Damazio
  */
@@ -64,6 +68,16 @@ public class SettingsActivity extends PreferenceActivity {
   protected void onCreate(Bundle icicle) {
     super.onCreate(icicle);
 
+    initActivityCommons();
+   
+    // If we only need the display setting screen nothing else needs to load.
+    if (processIntent())
+       return;
+      
+    initActivitySpecifics();
+  }
+  
+  private void initActivityCommons() {
     // The volume we want to control is the Text-To-Speech volume
     ApiFeatures apiFeatures = ApiFeatures.getInstance();
     int volumeStream =
@@ -93,11 +107,9 @@ public class SettingsActivity extends PreferenceActivity {
       announcementFrequency.setSummary(
           R.string.settings_not_available_summary);
     }
-   
-   // If we only need the display setting screen nothing else needs to load.
-   if (processIntent())
-      return;
-      
+  }
+  
+  private void initActivitySpecifics() {
     // Hook up switching of displayed list entries between metric and imperial
     // units
     CheckBoxPreference metricUnitsPreference =
@@ -126,7 +138,6 @@ public class SettingsActivity extends PreferenceActivity {
         return true;
       }
     });
-    
   }
   
   private boolean processIntent() {