Theming: add a SplashScreen for TrackListActivity.

src/main/AndroidManifest.xml

@@ -14,7 +14,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 -->
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
     package="de.dennisguse.opentracks"
     android:installLocation="auto">
 
@@ -138,7 +137,9 @@ limitations under the License.
 
         <activity android:name=".TrackEditActivity" />
 
-        <activity android:name=".TrackListActivity">
+        <activity
+            android:name=".TrackListActivity"
+            android:theme="@style/SplashTheme">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />

src/main/java/de/dennisguse/opentracks/TrackListActivity.java

@@ -214,6 +214,9 @@ public class TrackListActivity extends AbstractListActivity implements ConfirmDe
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
+        // Reset theme after splash
+        setTheme(R.style.ThemeCustom);
+
         super.onCreate(savedInstanceState);
 
         gpsStatusValue = GpsStatusValue.GPS_NONE;

src/main/res/drawable/splashscreen.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:opacity="opaque">
+
+    <!--    TODO DayNight: set background color for dayNight -->
+    <item android:drawable="@android:color/background_dark" />
+
+    <item
+        android:width="300dp"
+        android:height="300dp"
+        android:drawable="@drawable/ic_logo_color_108dp"
+        android:gravity="center_vertical|center_horizontal"
+        tools:targetApi="m" />
+
+</layer-list>

src/main/res/values/themes_custom.xml

@@ -60,4 +60,8 @@ limitations under the License.
         <item name="android:windowBackground">@android:color/transparent</item>
         <item name="android:windowIsFloating">true</item>
     </style>
+
+    <style name="SplashTheme" parent="ThemeCustom">
+        <item name="android:windowBackground">@drawable/splashscreen</item>
+    </style>
 </resources>