Widgetexplorer - wiring up

- add explorer subdirectory to shellpackge, add widgetexplorer filedefinition
- hook up containment added with a connection to showing the widget
  explorer
- memory management for widget explorer: create on demand, delete after
  close: Maybe we want to cache it? For now, go for reduced memory
  consumption rather than quick opening, and see how slow this might
  react.
- add QQuickView for widget explorer in desktopcorona

With this patch, I can open a widget explorer window from the QML
containment. Of course, the widget explorer is just a pink window right
now.

desktopcorona.cpp

@@ -22,6 +22,8 @@
 #include <QApplication>
 #include <QDebug>
 #include <QDesktopWidget>
+#include <QQuickView>
+
 #include <Plasma/Package>
 
 #include "panelview.h"
@@ -33,7 +35,8 @@ static const QString s_panelTemplatesPath("plasma-layout-templates/panels/*");
 
 DesktopCorona::DesktopCorona(QObject *parent)
     : Plasma::Corona(parent),
-      m_desktopWidget(QApplication::desktop())
+      m_desktopWidget(QApplication::desktop()),
+      m_widgetExplorer(0)
 {
     m_desktopDefaultsConfig = KConfigGroup(KSharedConfig::openConfig(package().filePath("defaults")), "Desktop");
 
@@ -43,6 +46,7 @@ DesktopCorona::DesktopCorona(QObject *parent)
             this, SLOT(screenCountChanged(int)));
     connect(m_desktopWidget, SIGNAL(workAreaResized(int)),
             this, SLOT(workAreaResized(int)));
+    connect(this, &DesktopCorona::containmentAdded, this, &DesktopCorona::handleContainmentAdded);
 
     connect(this, SIGNAL(screenOwnerChanged(int, int, Plasma::Containment *)),
             this, SLOT(updateScreenOwner(int, int, Plasma::Containment *)));
@@ -256,6 +260,39 @@ void DesktopCorona::updateScreenOwner(int wasScreen, int isScreen, Plasma::Conta
     }
 }
 
+void DesktopCorona::handleContainmentAdded(Plasma::Containment* c)
+{
+    connect(c, &Plasma::Containment::showAddWidgetsInterface, this, &DesktopCorona::showWidgetExplorer);
+}
+
+void DesktopCorona::showWidgetExplorer()
+{
+    if (!m_widgetExplorer) {
+        m_widgetExplorer = new QQuickView;
+        QString expqml = package().filePath("widgetexplorer");
+        qDebug() << "Script to load for WidgetExplorer: " << expqml;
+        m_widgetExplorer->setSource(QUrl::fromLocalFile(expqml));
+        connect(m_widgetExplorer, &QQuickView::statusChanged, this, &DesktopCorona::widgetExplorerStatusChanged);
+        connect(m_widgetExplorer, &QQuickView::visibleChanged, this, &DesktopCorona::widgetExplorerClosed);
+    }
+    m_widgetExplorer->show();
+}
+
+void DesktopCorona::widgetExplorerClosed(bool visible)
+{
+    if (!visible) {
+        m_widgetExplorer->deleteLater();
+        m_widgetExplorer = 0;
+    }
+}
+
+void DesktopCorona::widgetExplorerStatusChanged()
+{
+    foreach (QQmlError e, m_widgetExplorer->errors()) {
+        qWarning() << "Error in WidgetExplorer: " << e.toString();
+    }
+}
+
 void DesktopCorona::printScriptError(const QString &error)
 {
     qWarning() << error;

desktopcorona.h

@@ -24,6 +24,7 @@ class  *   Free Software Foundation, Inc.,
 #include "plasma/corona.h"
 
 class QDesktopWidget;
+class QQuickView;
 class PanelView;
 class View;
 
@@ -81,9 +82,16 @@ protected Q_SLOTS:
     void printScriptError(const QString &error);
     void printScriptMessage(const QString &message);
 
+private Q_SLOTS:
+    void handleContainmentAdded(Plasma::Containment *c);
+    void showWidgetExplorer();
+    void widgetExplorerClosed(bool visible);
+    void widgetExplorerStatusChanged();
+
 private:
     QDesktopWidget *m_desktopWidget;
     QList <View *> m_views;
+    QQuickView *m_widgetExplorer;
     QHash<Plasma::Containment *, PanelView *> m_panelViews;
     KConfigGroup m_desktopDefaultsConfig;
 };

shellpackage.cpp

@@ -31,6 +31,7 @@ void ShellPackageStructure::initPackage(Plasma::Package *package)
     //Directories
     package->addDirectoryDefinition("components", "components", i18n("UI components"));
     package->addDirectoryDefinition("views", "views", i18n("User interface for the views that will show containments"));
+    package->addDirectoryDefinition("explorer", "explorer", i18n("Explorer UI for adding widgets"));
 
     package->setMimeTypes("components", QStringList() << "text/x-qml");
     package->setMimeTypes("views", QStringList() << "text/x-qml");
@@ -46,7 +47,7 @@ void ShellPackageStructure::initPackage(Plasma::Package *package)
     package->addFileDefinition("compactapplet", "components/CompactApplet.qml", i18n("QML component that shows an applet in a popup"));
     package->addFileDefinition("configurationui", "components/Configuration.qml", i18n("QML component for the configuratuion dialog"));
     package->addFileDefinition("defaultcompactrepresentation", "components/DefaultCompactRepresentation.qml", i18n("Compact representation of an applet when collapsed in a popup, for instance as an icon. applets can override this component."));
-    package->addFileDefinition("widgetexplorer", "components/WidgetExplorer.qml", i18n("Widgets explorer UI"));
+    package->addFileDefinition("widgetexplorer", "explorer/WidgetExplorer.qml", i18n("Widgets explorer UI"));
     package->addFileDefinition("panelconfigurationui", "components/PanelConfiguration.qml", i18n("Panel configuration UI"));