* gaurd against an args with less than 2 items in it being passed in

* add a setFailedToLaunch method to applet to allow a generic way to set such status

it's pretty fugly looking at this point, but it works; i'll work with the artists to make it prettier later.

svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=687027

applet.cpp

@@ -18,11 +18,14 @@
 
 #include "applet.h"
 
+#include <QApplication>
 #include <QEvent>
 #include <QList>
+#include <QPainter>
 #include <QSize>
 #include <QTimer>
 
+#include <KDialog>
 #include <KPluginInfo>
 #include <KStandardDirs>
 #include <KService>
@@ -33,6 +36,10 @@
 #include "plasma/plasma.h"
 #include "plasma/svg.h"
 
+#include "plasma/widgets/widget.h"
+#include "plasma/widgets/lineedit.h"
+#include "plasma/widgets/vboxlayout.h"
+
 namespace Plasma
 {
 
@@ -44,10 +51,16 @@ class Applet::Private
               globalConfig( 0 ),
               appletConfig( 0 ),
               appletDescription(new KPluginInfo(appletDescription)),
+              background(0),
+              failureText(0),
               immutable(false),
               hasConfigurationInterface(false),
-              background(0)
+              failed(false)
         {
+            if (appletId == 0) {
+                appletId = nextId();
+            }
+
             if (appletId > s_maxAppletId) {
                 s_maxAppletId = appletId;
             }
@@ -68,6 +81,8 @@ class Applet::Private
             return s_maxAppletId;
         }
 
+        //TODO: examine the usage of memory here; there's a pretty large
+        //      number of members at this point.
         uint appletId;
         KSharedConfig::Ptr globalConfig;
         KSharedConfig::Ptr appletConfig;
@@ -75,18 +90,20 @@ class Applet::Private
         QList<QObject*> watchedForFocus;
         QStringList loadedEngines;
         static uint s_maxAppletId;
-        bool immutable;
-        bool hasConfigurationInterface;
         Plasma::Svg *background;
+        Plasma::LineEdit *failureText;
+        bool immutable : 1;
+        bool hasConfigurationInterface : 1;
+        bool failed : 1;
 };
 
 uint Applet::Private::s_maxAppletId = 0;
 
 Applet::Applet(QGraphicsItem *parent,
                const QString& serviceID,
-               int appletId)
+               uint appletId)
         : QObject(0),
-          QGraphicsItem(parent),
+          Widget(parent),
           d(new Private(KService::serviceByStorageId(serviceID), appletId))
 {
     init();
@@ -94,8 +111,9 @@ Applet::Applet(QGraphicsItem *parent,
 
 Applet::Applet(QObject* parent, const QStringList& args)
     : QObject(parent),
-      QGraphicsItem(0),
+      Widget(0),
-      d(new Private(KService::serviceByStorageId(args[0]), args[1].toInt()))
+      d(new Private(KService::serviceByStorageId(args.count() > 0 ? args[0] : QString()),
+                    args.count() > 1 ? args[1].toInt() : 0))
 {
     init();
     // the brain damage seen in the initialization list is due to the 
@@ -221,6 +239,57 @@ void Applet::setDrawStandardBackground(bool drawBackground)
     }
 }
 
+bool Applet::failedToLaunch() const
+{
+    return d->failed;
+}
+
+QString visibleFailureText(const QString& reason)
+{
+    QString text;
+
+    if (reason.isEmpty()) {
+        text = i18n("This object could not be created.");
+    } else {
+        text = i18n("This object could not be created for the following reason:<p>%1", reason);
+    }
+
+    return text;
+}
+
+void Applet::setFailedToLaunch(bool failed, const QString& reason)
+{
+    if (d->failed == failed) {
+        if (d->failureText) {
+            d->failureText->setHtml(visibleFailureText(reason));
+        }
+        return;
+    }
+
+    d->failed = failed;
+
+    qDeleteAll(QGraphicsItem::children());
+    delete layout();
+
+    if (failed) {
+        setDrawStandardBackground(failed || d->background != 0);
+        Layout* failureLayout = new VBoxLayout(this);
+        d->failureText = new LineEdit(this, scene());
+        d->failureText->setFlags(0);
+        d->failureText->setHtml(visibleFailureText(reason));
+        failureLayout->addItem(d->failureText);
+    } else {
+        d->failureText = 0;
+    }
+
+    update();
+}
+
+QRectF Applet::boundingRect () const
+{
+    //FIXME: this should be big enough to allow for the failure text?
+    return QRectF(300, 300, 300, 300);
+}
 
 void Applet::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
 {
@@ -229,9 +298,13 @@ void Applet::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QW
         d->background->paint(painter, boundingRect());
     }
 
+    if (d->failed) {
+        return;
+    }
+
     paintInterface(painter, option, widget);
 
-    //TODO: interface overlays on hover?
+    //TODO: interface overlays on hover
 }
 
 void Applet::paintInterface(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)

applet.h

@@ -27,6 +27,7 @@
 #include <kgenericfactory.h>
 
 #include <plasma/plasma.h>
+#include <plasma/widgets/widget.h>
 
 namespace Plasma
 {
@@ -38,7 +39,7 @@ class DataEngine;
  *
  *
  */
-class PLASMA_EXPORT Applet : public QObject, public QGraphicsItem
+class PLASMA_EXPORT Applet : public QObject, public Widget
 {
     Q_OBJECT
 
@@ -53,9 +54,9 @@ class PLASMA_EXPORT Applet : public QObject, public QGraphicsItem
          * @arg appletId a unique id used to differentiate between multiple
          *      instances of the same Applet type
          */
-        Applet(QGraphicsItem* parent,
+        explicit Applet(QGraphicsItem* parent = 0,
-               const QString& serviceId,
+                        const QString& serviceId = QString(),
-               int appletId);
+                        uint appletId = 0);
 
         /**
          * This constructor is to be used with the plugin loading systems
@@ -265,9 +266,31 @@ class PLASMA_EXPORT Applet : public QObject, public QGraphicsItem
          **/
         void setDrawStandardBackground(bool drawBackground);
 
+        /**
+         * If for some reason, the applet fails to get up on its feet (the
+         * library couldn't be loaded, necessary hardware support wasn't found,
+         * etc..) this method returns true
+         **/
+        bool failedToLaunch() const;
+
+        /**
+         * Call this method when the applet fails to launch properly. An
+         * optional reason can be provided.
+         *
+         * Not that all children items will be deleted when this method is
+         * called. If you have pointers to these items, you will need to
+         * reset them after calling this method.
+         *
+         * @param failed true when the applet failed, false when it succeeded
+         * @param reason an optional reason to show the user why the applet
+         *               failed to launch
+         **/
+        void setFailedToLaunch(bool failed, const QString& reason = QString());
+
         // Reimplemented from QGraphicsItem
         enum { Type = Plasma::AppletType };
         int type() const { return Type; }
+        QRectF boundingRect () const;
 
     Q_SIGNALS:
         /**