wallpapers/image: fix apply button not being enabled after adding wallpapers

Enable the apply button after:

1. Drag and drop
2. Add an image using the file dialog
3. Delete an image that is not the currently selected one

wallpapers/image/imagepackage/contents/ui/WallpaperDelegate.qml

@@ -50,6 +50,8 @@ KCM.GridDelegate {
                 if (wallpapersGrid.view.currentIndex === index) {
                     const newIndex = (index + 1) % (imageModel.count - 1);
                     wallpapersGrid.view.itemAtIndex(newIndex).clicked();
+                } else {
+                    root.configurationChanged();
                 }
             }
         }

wallpapers/image/imagepackage/contents/ui/config.qml

@@ -39,6 +39,8 @@ ColumnLayout {
     property var cfg_UncheckedSlides: []
     property var cfg_UncheckedSlidesDefault: []
 
+    signal configurationChanged()
+
     function saveConfig() {
         if (configDialog.currentWallpaper === "org.kde.image") {
             imageWallpaper.wallpaperModel.commitAddition();
@@ -60,6 +62,8 @@ ColumnLayout {
         onUncheckedSlidesChanged: cfg_UncheckedSlides = uncheckedSlides
         onSlideshowModeChanged: cfg_SlideshowMode = slideshowMode
         onSlideshowFoldersFirstChanged: cfg_SlideshowFoldersFirst = slideshowFoldersFirst
+
+        onSettingsChanged: root.configurationChanged()
     }
 
     onCfg_FillModeChanged: {

wallpapers/image/plugin/imagebackend.cpp

@@ -518,6 +518,8 @@ void ImageBackend::slotWallpaperBrowseCompleted()
     for (const QString &p : selectedFiles) {
         m_model->addBackground(p);
     }
+
+    Q_EMIT settingsChanged();
 }
 
 QString ImageBackend::addUsersWallpaper(const QUrl &url)
@@ -534,6 +536,8 @@ QString ImageBackend::addUsersWallpaper(const QUrl &url)
         return QString();
     }
 
+    Q_EMIT settingsChanged();
+
     return results.at(0);
 }
 

wallpapers/image/plugin/imagebackend.h

@@ -127,7 +127,7 @@ public Q_SLOTS:
     void slotSlideModelDataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles);
 
 Q_SIGNALS:
-    void settingsChanged(bool);
+    void settingsChanged();
     void imageChanged();
     void modelImageChanged();
     void renderingModeChanged();