Don't duplicate colors, use the theme #757

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/ControlCenterv2.java

@@ -197,7 +197,7 @@ public class ControlCenterv2 extends AppCompatActivity
             checkAndRequestPermissions();
         }
 
-        ChangeLog cl = new ChangeLog(this, (GBApplication.isDarkThemeEnabled() ? "body { color: #ffffff; background-color: #282828; }\n" : "") + DEFAULT_CSS);
+        ChangeLog cl = createChangeLog();
         if (cl.isFirstRun()) {
             cl.getLogDialog().show();
         }
@@ -251,7 +251,7 @@ public class ControlCenterv2 extends AppCompatActivity
                 GBApplication.quit();
                 return true;
             case R.id.external_changelog:
-                ChangeLog cl = new ChangeLog(this, (GBApplication.isDarkThemeEnabled() ? "body { color: #ffffff; background-color: #282828; }\n" : "") + DEFAULT_CSS);
+                ChangeLog cl = createChangeLog();
                 cl.getFullLogDialog().show();
                 return true;
         }
@@ -259,6 +259,14 @@ public class ControlCenterv2 extends AppCompatActivity
         return true;
     }
 
+    private ChangeLog createChangeLog() {
+        String css = ChangeLog.DEFAULT_CSS;
+        css += "body { "
+                + "color: " + AndroidUtils.getTextColorHex(getBaseContext()) + "; "
+                + "background-color: " + AndroidUtils.getBackgroundColorHex(getBaseContext()) + ";" +
+                "}";
+        return new ChangeLog(this, css);
+}
     private void launchDiscoveryActivity() {
         startActivity(new Intent(this, DiscoveryActivity.class));
     }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/AndroidUtils.java

@@ -20,12 +20,16 @@ import android.app.Activity;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.res.Configuration;
+import android.graphics.Color;
 import android.os.ParcelUuid;
 import android.os.Parcelable;
 import android.support.v4.content.LocalBroadcastManager;
 
 import java.util.Locale;
 
+import nodomain.freeyourgadget.gadgetbridge.GBApplication;
+import nodomain.freeyourgadget.gadgetbridge.R;
+
 public class AndroidUtils {
     public static ParcelUuid[] toParcelUUids(Parcelable[] uuids) {
         if (uuids == null) {
@@ -74,4 +78,39 @@ public class AndroidUtils {
         activity.getBaseContext().getResources().updateConfiguration(config, activity.getBaseContext().getResources().getDisplayMetrics());
         activity.recreate();
     }
+
+    /**
+     * Returns the theme dependent text color as a css-style hex string.
+     * @param context the context to access the colour
+     */
+    public static String getTextColorHex(Context context) {
+        int color;
+        if (GBApplication.isDarkThemeEnabled()) {
+            color = context.getResources().getColor(R.color.primarytext_dark);
+        } else {
+            color = context.getResources().getColor(R.color.primarytext_light);
+        }
+        return colorToHex(color);
+    }
+
+    /**
+     * Returns the theme dependent background color as a css-style hex string.
+     * @param context the context to access the colour
+     */
+    public static String getBackgroundColorHex(Context context) {
+        int color;
+        if (GBApplication.isDarkThemeEnabled()) {
+            color = context.getResources().getColor(R.color.cardview_dark_background);
+        } else {
+            color = context.getResources().getColor(R.color.cardview_light_background);
+        }
+        return colorToHex(color);
+    }
+
+    private static String colorToHex(int color) {
+        return "#"
+                + Integer.toHexString(Color.red(color))
+                + Integer.toHexString(Color.green(color))
+                + Integer.toHexString(Color.blue(color));
+    }
 }