Set white logo in dark themes programmatically

As `?attr/welcome_logo` in `nav_header_main.xml/imageView` always
selects the default, black icon, we change the icon in the `onCreate()`
method for dark themes.

Author: NWuensche

app/src/main/java/fr/gaulupeau/apps/Poche/ui/MainActivity.java

@@ -28,6 +28,7 @@
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
+import android.widget.ImageView;
 import android.widget.ProgressBar;
 import android.widget.TextView;
 import android.widget.Toast;
@@ -134,6 +135,12 @@ protected void onCreate(Bundle savedInstanceState) {
                 lastUpdateTimeView = (TextView)headerView.findViewById(R.id.lastUpdateTime);
             }
 
+            // Set white logo in the navigation bar in dark and dark (high contrast) theme
+            if (headerView != null && Themes.getCurrentTheme() != null && Themes.getCurrentTheme().isDark()) {
+                ImageView logo = headerView.findViewById(R.id.imageView);
+                logo.setImageDrawable(getDrawable(R.drawable.welcome_white));
+            }
+
             // Set different colors for items in the navigation bar in dark (high contrast) theme
             if (Themes.getCurrentTheme() != null && Themes.getCurrentTheme() == Themes.Theme.DARK_CONTRAST) {
                 @SuppressLint("ResourceType") XmlResourceParser parser = getResources().getXml(R.color.dark_contrast_menu_item);

app/src/main/java/fr/gaulupeau/apps/Poche/ui/Themes.java

@@ -119,6 +119,10 @@ public enum Theme {
             return proxyResId;
         }
 
+        public boolean isDark() {
+            return this == Themes.Theme.DARK || this == Themes.Theme.DARK_CONTRAST;
+        }
+
     }
 
 }