WelcomePage: bug fix for example view

We have to wait for all of the QtVersionManager and HelpManager to
be initialized, and some data actually being requested from the
examples model, before showing any examples.

Task-number: QTBUG-33924

Change-Id: I189710374f4af8d7d9cbe4731fa3faafd0623ffb
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>

src/plugins/qtsupport/exampleslistmodel.cpp

@@ -110,11 +110,6 @@ public:
 
     void setupQtVersions()
     {
-        if (!QtVersionManager::isLoaded()) {
-            connect(QtVersionManager::instance(), SIGNAL(qtVersionsLoaded()), this, SLOT(qtVersionManagerLoaded()));
-            return;
-        }
-
         beginResetModel();
         clear();
 
@@ -178,18 +173,10 @@ public slots:
         QVariant variant = data(modelIndex, Qt::UserRole + 2);
         return variant;
     }
-    void qtVersionManagerLoaded()
-    {
-        disconnect(QtVersionManager::instance(), SIGNAL(qtVersionsLoaded()), this, SLOT(qtVersionManagerLoaded()));
-        setupQtVersions();
-    }
 };
 
 ExamplesListModel::ExamplesListModel(QObject *parent) :
     QAbstractListModel(parent),
-    m_updateOnQtVersionsChanged(false),
-    m_initialized(false),
-    m_helpInitialized(false),
     m_uniqueQtId(noQtVersionsId)
 {
     QHash<int, QByteArray> roleNames;
@@ -210,13 +197,6 @@ ExamplesListModel::ExamplesListModel(QObject *parent) :
     roleNames[Platforms] = "platforms";
     roleNames[IsHighlighted] = "isHighlighted";
     setRoleNames(roleNames);
-
-    connect(Core::HelpManager::instance(), SIGNAL(setupFinished()),
-            SLOT(helpInitialized()));
-    connect(QtVersionManager::instance(), SIGNAL(qtVersionsChanged(QList<int>,QList<int>,QList<int>)),
-            this, SLOT(handleQtVersionsChanged()));
-    connect(ProjectExplorer::KitManager::instance(), SIGNAL(defaultkitChanged()),
-            SLOT(handleQtVersionsChanged()));
 }
 
 static QString fixStringForTags(const QString &string)
@@ -430,14 +410,6 @@ void ExamplesListModel::parseTutorials(QXmlStreamReader *reader, const QString &
     }
 }
 
-void ExamplesListModel::handleQtVersionsChanged()
-{
-    if (m_updateOnQtVersionsChanged) {
-        emit qtVersionsChanged();
-        updateExamples();
-    }
-}
-
 void ExamplesListModel::updateExamples()
 {
     QString examplesInstallPath;
@@ -541,7 +513,6 @@ QStringList ExamplesListModel::exampleSources(QString *examplesInstallPath, QStr
         return sources;
 
     // try to find a suitable Qt version
-    m_updateOnQtVersionsChanged = true; // this must be updated when the Qt versions change
     // fallbacks are passed back if no example manifest is found
     // and we fallback to Qt Creator's shipped manifest (e.g. only old Qt Versions found)
     QString potentialExamplesFallback;
@@ -623,7 +594,6 @@ QStringList ExamplesListModel::exampleSources(QString *examplesInstallPath, QStr
 
 int ExamplesListModel::rowCount(const QModelIndex &) const
 {
-    ensureInitialized();
     return m_exampleItems.size();
 }
 
@@ -636,7 +606,6 @@ QString prefixForItem(const ExampleItem &item)
 
 QVariant ExamplesListModel::data(const QModelIndex &index, int role) const
 {
-    ensureInitialized();
     if (!index.isValid() || index.row()+1 > m_exampleItems.count()) {
         qDebug() << Q_FUNC_INFO << "invalid index requested";
         return QVariant();
@@ -685,37 +654,17 @@ QVariant ExamplesListModel::data(const QModelIndex &index, int role) const
     }
 }
 
+// TODO global tag list is unused, remove
 QStringList ExamplesListModel::tags() const
 {
-    ensureInitialized();
     return m_tags;
 }
 
-void ExamplesListModel::helpInitialized()
+void ExamplesListModel::setUniqueQtId(int id)
 {
-    m_helpInitialized = true;
-    if (m_initialized) // if we are already initialized we need to update nevertheless
-        updateExamples();
-}
-
-void ExamplesListModel::ensureInitialized() const
-{
-    if (m_initialized || !m_helpInitialized)
-        return;
-    ExamplesListModel *that = const_cast<ExamplesListModel *>(this);
-    that->m_initialized = true;
-    that->updateExamples();
-    emit that->qtVersionsChanged();
-}
-
-void ExamplesListModel::filterForQtById(int id)
-{
-    if (QtVersionManager::isLoaded()) {
     m_uniqueQtId = id;
-        setUniqueQtVersionIdSetting(id);
     updateExamples();
 }
-}
 
 ExamplesListModelFilter::ExamplesListModelFilter(ExamplesListModel *sourceModel, QObject *parent) :
     QSortFilterProxyModel(parent),
@@ -723,12 +672,21 @@ ExamplesListModelFilter::ExamplesListModelFilter(ExamplesListModel *sourceModel,
     m_sourceModel(sourceModel),
     m_timerId(0),
     m_qtVersionModel(new QtVersionsModel(this)),
-    m_blockIndexUpdate(false)
+    m_blockIndexUpdate(false),
+    m_qtVersionManagerInitialized(false),
+    m_helpManagerInitialized(false),
+    m_initalized(false),
+    m_exampleDataRequested(false)
 {
+    // initialization hooks
+    connect(QtVersionManager::instance(), SIGNAL(qtVersionsLoaded()),
+            this, SLOT(qtVersionManagerLoaded()));
+    connect(Core::HelpManager::instance(), SIGNAL(setupFinished()),
+            this, SLOT(helpManagerInitialized()));
+
     connect(this, SIGNAL(showTutorialsOnlyChanged()), SLOT(updateFilter()));
-    connect(sourceModel, SIGNAL(qtVersionsChanged()), SLOT(handleQtVersionsChanged()));
+
     setSourceModel(m_sourceModel);
-    m_qtVersionModel->setupQtVersions();
 }
 
 void ExamplesListModelFilter::updateFilter()
@@ -796,13 +754,13 @@ bool ExamplesListModelFilter::filterAcceptsRow(int sourceRow, const QModelIndex
 
 int ExamplesListModelFilter::rowCount(const QModelIndex &parent) const
 {
-    m_sourceModel->ensureInitialized();
+    exampleDataRequested();
     return QSortFilterProxyModel::rowCount(parent);
 }
 
 QVariant ExamplesListModelFilter::data(const QModelIndex &index, int role) const
 {
-    m_sourceModel->ensureInitialized();
+    exampleDataRequested();
     return QSortFilterProxyModel::data(index, role);
 }
 
@@ -811,6 +769,15 @@ QAbstractItemModel* ExamplesListModelFilter::qtVersionModel()
     return m_qtVersionModel;
 }
 
+void ExamplesListModelFilter::filterForQtById(int id)
+{
+    if (m_blockIndexUpdate || !m_initalized)
+        return;
+
+    setUniqueQtVersionIdSetting(id);
+    m_sourceModel->setUniqueQtId(id);
+}
+
 void ExamplesListModelFilter::setShowTutorialsOnly(bool showTutorialsOnly)
 {
     m_showTutorialsOnly = showTutorialsOnly;
@@ -821,10 +788,44 @@ void ExamplesListModelFilter::handleQtVersionsChanged()
 {
     m_blockIndexUpdate = true;
     m_qtVersionModel->setupQtVersions();
+    m_sourceModel->updateExamples();
     emit qtVersionIndexChanged();
     m_blockIndexUpdate = false;
 }
 
+void ExamplesListModelFilter::qtVersionManagerLoaded()
+{
+    m_qtVersionManagerInitialized = true;
+    tryToInitialize();
+}
+
+void ExamplesListModelFilter::helpManagerInitialized()
+{
+    m_helpManagerInitialized = true;
+    tryToInitialize();
+}
+
+void ExamplesListModelFilter::exampleDataRequested() const
+{
+    ExamplesListModelFilter *that = const_cast<ExamplesListModelFilter *>(this);
+    that->m_exampleDataRequested = true;
+    that->tryToInitialize();
+}
+
+void ExamplesListModelFilter::tryToInitialize()
+{
+    if (!m_initalized
+            && m_qtVersionManagerInitialized && m_helpManagerInitialized && m_exampleDataRequested) {
+        m_initalized = true;
+        connect(QtVersionManager::instance(), SIGNAL(qtVersionsChanged(QList<int>,QList<int>,QList<int>)),
+                this, SLOT(handleQtVersionsChanged()));
+        connect(ProjectExplorer::KitManager::instance(), SIGNAL(defaultkitChanged()),
+                this, SLOT(handleQtVersionsChanged()));
+        handleQtVersionsChanged();
+        m_sourceModel->updateExamples();
+    }
+}
+
 void ExamplesListModelFilter::delayedUpdateFilter()
 {
     if (m_timerId != 0)

src/plugins/qtsupport/exampleslistmodel.h

@@ -85,21 +85,15 @@ public:
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
 
     QStringList tags() const;
-    void ensureInitialized() const;
 
     void beginReset() { beginResetModel(); }
     void endReset() { endResetModel(); }
 
-    void filterForQtById(int id);
+    void setUniqueQtId(int id);
+    void updateExamples();
 
 signals:
     void tagsUpdated();
-    void qtVersionsChanged();
-
-public slots:
-    void handleQtVersionsChanged();
-    void updateExamples();
-    void helpInitialized();
 
 private:
     void parseExamples(QXmlStreamReader *reader, const QString &projectsOffset,
@@ -113,9 +107,6 @@ private:
 
     QList<ExampleItem> m_exampleItems;
     QStringList m_tags;
-    bool m_updateOnQtVersionsChanged;
-    bool m_initialized;
-    bool m_helpInitialized;
     int m_uniqueQtId;
 };
 
@@ -143,13 +134,7 @@ public:
     QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const;
     QAbstractItemModel* qtVersionModel();
 
-    Q_INVOKABLE void filterForQtById(int id)
+    Q_INVOKABLE void filterForQtById(int id);
-    {
-        if (m_blockIndexUpdate)
-            return;
-
-        m_sourceModel->filterForQtById(id);
-    }
 
 public slots:
     void setFilterTags(const QStringList &arg)
@@ -180,7 +165,13 @@ signals:
     void searchStrings(const QStringList &arg);
     void qtVersionIndexChanged();
 
+private slots:
+    void qtVersionManagerLoaded();
+    void helpManagerInitialized();
+
 private:
+    void exampleDataRequested() const;
+    void tryToInitialize();
     void timerEvent(QTimerEvent *event);
     void delayedUpdateFilter();
     int qtVersionIndex() const;
@@ -192,6 +183,10 @@ private:
     int m_timerId;
     QtVersionsModel* m_qtVersionModel;
     bool m_blockIndexUpdate;
+    bool m_qtVersionManagerInitialized;
+    bool m_helpManagerInitialized;
+    bool m_initalized;
+    bool m_exampleDataRequested;
 };
 
 } // namespace Internal