Fix default opacity for existing widgets

app/src/main/java/org/tasks/preferences/fragments/ScrollableWidget.kt

@@ -59,7 +59,7 @@ class ScrollableWidget : InjectingPreferenceFragment() {
 
         val row = setupSlider(R.string.p_widget_opacity, 100)
         val header = setupSlider(R.string.p_widget_header_opacity, row.value)
-        val footer = setupSlider(R.string.p_widget_empty_space_opacity, row.value)
+        val footer = setupSlider(R.string.p_widget_footer_opacity, row.value)
 
         val opacity = findPreference(R.string.opacity) as SeekBarPreference
         opacity.value = max(header.value, row.value, footer.value)

app/src/main/java/org/tasks/widget/TasksWidget.java

@@ -100,7 +100,7 @@ public class TasksWidget extends InjectingAppWidgetProvider {
     remoteViews.setInt(
         R.id.empty_view,
         "setBackgroundColor",
-        ColorUtils.setAlphaComponent(bgColor, widgetPreferences.getEmptySpaceOpacity()));
+        ColorUtils.setAlphaComponent(bgColor, widgetPreferences.getFooterOpacity()));
 
     Filter filter = defaultFilterProvider.getFilterFromPreference(filterId);
     remoteViews.setTextViewText(R.id.widget_title, filter.listingTitle);

app/src/main/java/org/tasks/widget/WidgetPreferences.java

@@ -90,23 +90,29 @@ public class WidgetPreferences {
   }
 
   int getHeaderOpacity() {
-    return getAlphaValue(R.string.p_widget_header_opacity);
+    int headerOpacity = preferences.getInt(getKey(R.string.p_widget_header_opacity), -1);
+    return headerOpacity >= 0 && headerOpacity <= 100
+        ? getAlphaValue(headerOpacity)
+        : getRowOpacity();
   }
 
-  int getRowOpacity() {
-    return getAlphaValue(R.string.p_widget_opacity);
+  int getFooterOpacity() {
+    int footerOpacity = preferences.getInt(getKey(R.string.p_widget_footer_opacity), -1);
+    return footerOpacity >= 0 && footerOpacity <= 100
+        ? getAlphaValue(footerOpacity)
+        : getRowOpacity();
   }
 
-  int getEmptySpaceOpacity() {
-    return getAlphaValue(R.string.p_widget_empty_space_opacity);
+  int getRowOpacity() {
+    return getAlphaValue(preferences.getInt(getKey(R.string.p_widget_opacity), 100));
   }
 
   boolean openOnEmptySpaceClick() {
     return preferences.getIntegerFromString(getKey(R.string.p_widget_empty_space_click), 0) == 1;
   }
 
-  private int getAlphaValue(int resId) {
-    return (int) ((preferences.getInt(getKey(resId), 100) / 100.0) * 255.0);
+  private int getAlphaValue(int percentage) {
+    return (int) (percentage / 100.0 * 255.0);
   }
 
   public void setColor(int color) {

app/src/main/res/values/keys.xml

@@ -300,7 +300,7 @@
   <string name="p_widget_show_settings">widget-show-settings-</string>
   <string name="p_widget_show_menu">widget-show-menu-</string>
   <string name="p_widget_header_opacity">widget-header-opacity-</string>
-  <string name="p_widget_empty_space_opacity">widget-empty-space-opacity-</string>
+  <string name="p_widget_footer_opacity">widget-empty-space-opacity-</string>
   <string name="p_widget_empty_space_click">widget-empty-space-click-</string>
   <string name="p_widget_due_date_position">widget-due-date-position-</string>
   <string name="p_widget_spacing">widget-spacing-</string>

app/src/main/res/xml/preferences_widget.xml

@@ -43,7 +43,7 @@
 
     <SeekBarPreference
       android:defaultValue="100"
-      android:key="@string/p_widget_empty_space_opacity"
+      android:key="@string/p_widget_footer_opacity"
       android:max="100"
       android:title="@string/opacity_footer"
       app:min="0"