Preview default threshold battery colours

app/src/main/java/se/ajpanton/statusbartweak/shell/ui/BatteryBarFragment.java

@@ -278,6 +278,14 @@ public final class BatteryBarFragment extends Fragment {
                                          int labelRes,
                                          String colour,
                                          int emptyLabelRes) {
+        updateColourButtonLabel(button, labelRes, colour, emptyLabelRes, "");
+    }
+
+    private void updateColourButtonLabel(MaterialButton button,
+                                         int labelRes,
+                                         String colour,
+                                         int emptyLabelRes,
+                                         String defaultPreviewColour) {
         if (button == null) {
             return;
         }
@@ -287,6 +295,11 @@ public final class BatteryBarFragment extends Fragment {
         boolean hasBackground = false;
         if (BatteryBarStyle.isThresholdChargeDefault(colour)) {
             value = getString(R.string.battery_bar_colour_same_as_default);
+            String defaultPreview = BatteryBarStyle.normalizeColor(defaultPreviewColour);
+            if (!defaultPreview.isEmpty()) {
+                backgroundColor = resolvePreviewColour(defaultPreview);
+                hasBackground = true;
+            }
         } else if (normalised.isEmpty()) {
             value = getString(emptyLabelRes);
         } else {
@@ -962,11 +975,19 @@ public final class BatteryBarFragment extends Fragment {
             row.addView(dischargeButton);
 
             MaterialButton chargeButton = createRowButton(context);
+            String defaultChargeColour = prefs.getString(
+                    SbtSettings.KEY_BATTERY_BAR_DEFAULT_CHARGE_COLOR,
+                    SbtDefaults.BATTERY_BAR_DEFAULT_CHARGE_COLOR_DEFAULT);
+            String thresholdDefaultPreview = BatteryBarStyle.normalizeColor(defaultChargeColour);
+            if (thresholdDefaultPreview.isEmpty()) {
+                thresholdDefaultPreview = threshold.dischargeColor;
+            }
             updateColourButtonLabel(
                     chargeButton,
                     R.string.battery_bar_threshold_charge_colour,
                     threshold.chargeColor,
-                    R.string.battery_bar_colour_same_as_default);
+                    R.string.battery_bar_colour_same_as_default,
+                    thresholdDefaultPreview);
             chargeButton.setOnClickListener(v -> showThresholdColourDialog(
                     threshold,
                     false,