[libcalamaresui] Remove *next* button from ViewManager

- add properties for the next button (enabled, label, icon...)
- update those properties as normal
- connect to the properties in the UI implementation

src/calamares/CalamaresWindow.cpp

@@ -150,6 +150,16 @@ getButtonIcon( const QString& name )
     return Calamares::Branding::instance()->image( name, QSize( 22, 22 ) );
 }
 
+static inline void
+setButtonIcon( QPushButton* button, const QString& name )
+{
+    auto icon = getButtonIcon( name );
+    if ( button && !icon.isNull() )
+    {
+        button->setIcon( icon );
+    }
+}
+
 QWidget*
 CalamaresWindow::getWidgetNavigation()
 {
@@ -162,6 +172,10 @@ CalamaresWindow::getWidgetNavigation()
     auto* next = new QPushButton( getButtonIcon( QStringLiteral( "go-next" ) ), tr( "&Next" ), navigation );
     next->setObjectName( "view-button-next" );
     connect( next, &QPushButton::clicked, m_viewManager, &Calamares::ViewManager::next );
+    connect( m_viewManager, &Calamares::ViewManager::nextEnabledChanged, next, &QPushButton::setEnabled );
+    connect( m_viewManager, &Calamares::ViewManager::nextLabelChanged, next, &QPushButton::setText );
+    connect(
+        m_viewManager, &Calamares::ViewManager::nextIconChanged, this, [=]( QString n ) { setButtonIcon( next, n ); } );
     auto* quit = new QPushButton( getButtonIcon( QStringLiteral( "dialog-cancel" ) ), tr( "&Cancel" ), navigation );
     quit->setObjectName( "view-button-cancel" );
     connect( quit, &QPushButton::clicked, m_viewManager, &Calamares::ViewManager::quit );

src/libcalamaresui/ViewManager.cpp

@@ -91,8 +91,6 @@ ViewManager::ViewManager( QObject* parent )
     // Create buttons and sets an initial icon; the icons may change
     m_back = new QPushButton( getButtonIcon( QStringLiteral( "go-previous" ) ), tr( "&Back" ), m_widget );
     m_back->setObjectName( "view-button-back" );
-    m_next = new QPushButton( getButtonIcon( QStringLiteral( "go-next" ) ), tr( "&Next" ), m_widget );
-    m_next->setObjectName( "view-button-next" );
     m_quit = new QPushButton( getButtonIcon( QStringLiteral( "dialog-cancel" ) ), tr( "&Cancel" ), m_widget );
     m_quit->setObjectName( "view-button-cancel" );
 
@@ -102,11 +100,9 @@ ViewManager::ViewManager( QObject* parent )
     mainLayout->addLayout( bottomLayout );
     bottomLayout->addStretch();
     bottomLayout->addWidget( m_back );
-    bottomLayout->addWidget( m_next );
     bottomLayout->addSpacing( 12 );
     bottomLayout->addWidget( m_quit );
 
-    connect( m_next, &QPushButton::clicked, this, &ViewManager::next );
     connect( m_back, &QPushButton::clicked, this, &ViewManager::back );
     connect( m_quit, &QPushButton::clicked, this, &ViewManager::quit );
     m_back->setEnabled( false );
@@ -142,7 +138,8 @@ ViewManager::addViewStep( ViewStep* step )
     // If this is the first inserted view step, update status of "Next" button
     if ( m_steps.count() == 1 )
     {
-        m_next->setEnabled( step->isNextEnabled() );
+        m_nextEnabled = step->isNextEnabled();
+        emit nextEnabledChanged( m_nextEnabled );
     }
 }
 
@@ -153,13 +150,15 @@ ViewManager::insertViewStep( int before, ViewStep* step )
     emit beginInsertRows( QModelIndex(), before, before );
     m_steps.insert( before, step );
     connect( step, &ViewStep::enlarge, this, &ViewManager::enlarge );
+    // TODO: this can be a regular slot
     connect( step, &ViewStep::nextStatusChanged, this, [this]( bool status ) {
         ViewStep* vs = qobject_cast< ViewStep* >( sender() );
         if ( vs )
         {
             if ( vs == m_steps.at( m_currentStep ) )
             {
-                m_next->setEnabled( status );
+                m_nextEnabled = status;
+                emit nextEnabledChanged( m_nextEnabled );
             }
         }
     } );
@@ -364,7 +363,8 @@ ViewManager::next()
         {
             // Reached the end in a weird state (e.g. no finished step after an exec)
             executing = false;
-            m_next->setEnabled( false );
+            m_nextEnabled = false;
+            emit nextEnabledChanged( m_nextEnabled );
             m_back->setEnabled( false );
         }
         updateCancelEnabled( !settings->disableCancel() && !( executing && settings->disableCancelDuringExec() ) );
@@ -376,7 +376,8 @@ ViewManager::next()
 
     if ( m_currentStep < m_steps.count() )
     {
-        m_next->setEnabled( !executing && m_steps.at( m_currentStep )->isNextEnabled() );
+        m_nextEnabled = !executing && m_steps.at( m_currentStep )->isNextEnabled();
+        emit nextEnabledChanged( m_nextEnabled );
         m_back->setEnabled( !executing && m_steps.at( m_currentStep )->isBackEnabled() );
     }
 
@@ -399,13 +400,17 @@ ViewManager::updateButtonLabels()
     // If we're going into the execution step / install phase, other message
     if ( stepIsExecute( m_steps, m_currentStep + 1 ) )
     {
-        m_next->setText( nextIsInstallationStep );
-        setButtonIcon( m_next, "run-install" );
+        m_nextLabel = nextIsInstallationStep;
+        m_nextIcon = "run-install";
+        emit nextLabelChanged( m_nextLabel );
+        emit nextIconChanged( m_nextIcon );
     }
     else
     {
-        m_next->setText( tr( "&Next" ) );
-        setButtonIcon( m_next, "go-next" );
+        m_nextLabel = tr( "&Next" );
+        m_nextIcon = "go-next";
+        emit nextLabelChanged( m_nextLabel );
+        emit nextIconChanged( m_nextIcon );
     }
 
     // Going back is always simple
@@ -460,7 +465,8 @@ ViewManager::back()
         return;
     }
 
-    m_next->setEnabled( m_steps.at( m_currentStep )->isNextEnabled() );
+    m_nextEnabled = m_steps.at( m_currentStep )->isNextEnabled();
+    emit nextEnabledChanged( m_nextEnabled );
     m_back->setEnabled( m_steps.at( m_currentStep )->isBackEnabled() );
 
     if ( m_currentStep == 0 && m_steps.first()->isAtBeginning() )

src/libcalamaresui/ViewManager.h

@@ -38,6 +38,9 @@ class UIDLLEXPORT ViewManager : public QAbstractListModel
 {
     Q_OBJECT
     Q_PROPERTY( int currentStepIndex READ currentStepIndex NOTIFY currentStepChanged FINAL )
+    Q_PROPERTY( bool nextEnabled READ nextEnabled NOTIFY nextEnabledChanged FINAL )
+    Q_PROPERTY( QString nextLabel READ nextLabel NOTIFY nextLabelChanged FINAL )
+    Q_PROPERTY( QString nextIcon READ nextIcon NOTIFY nextIconChanged FINAL )
 
 public:
     /**
@@ -99,6 +102,18 @@ public Q_SLOTS:
      * have any more pages.
      */
     void next();
+    bool nextEnabled() const
+    {
+        return m_nextEnabled;  ///< Is the next-button to be enabled
+    }
+    QString nextLabel() const
+    {
+        return m_nextLabel;  ///< What should be displayed on the next-button
+    }
+    QString nextIcon() const
+    {
+        return m_nextIcon;  ///< Name of the icon to show
+    }
 
     /**
      * @brief back moves backward to the previous page of the current ViewStep (if any),
@@ -133,6 +148,10 @@ signals:
     void enlarge( QSize enlarge ) const;  // See ViewStep::enlarge()
     void cancelEnabled( bool enabled ) const;
 
+    void nextEnabledChanged( bool ) const;
+    void nextLabelChanged( QString ) const;
+    void nextIconChanged( QString ) const;
+
 private:
     explicit ViewManager( QObject* parent = nullptr );
     virtual ~ViewManager() override;
@@ -149,9 +168,12 @@ private:
     QWidget* m_widget;
     QStackedWidget* m_stack;
     QPushButton* m_back;
-    QPushButton* m_next;
     QPushButton* m_quit;
 
+    bool m_nextEnabled = false;
+    QString m_nextLabel;
+    QString m_nextIcon;  ///< Name of icon to show on button
+
 public:
     /** @section Model
      *