[FEATURE] Layer tree view indicator for non-removable (required) layers

qgis · Sep 11, 2018 · b8197ed · b8197ed
1 parent 602b3e9
commit b8197ed
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diff --git a/src/app/CMakeLists.txt b/src/app/CMakeLists.txt
@@ -58,6 +58,7 @@ SET(QGIS_APP_SRCS
   qgslayertreeviewembeddedindicator.cpp
   qgslayertreeviewfilterindicator.cpp
   qgslayertreeviewmemoryindicator.cpp
+  qgslayertreeviewnonremovableindicator.cpp
   qgsloadstylefromdbdialog.cpp
   qgsmapcanvasdockwidget.cpp
   qgsmaplayerstyleguiutils.cpp
@@ -281,6 +282,7 @@ SET (QGIS_APP_MOC_HDRS
   qgslayertreeviewembeddedindicator.h
   qgslayertreeviewmemoryindicator.h
   qgslayertreeviewfilterindicator.h
+  qgslayertreeviewnonremovableindicator.h
   qgsloadstylefromdbdialog.h
   qgsmapcanvasdockwidget.h
   qgsmaplayerstyleguiutils.h

diff --git a/src/app/qgisapp.cpp b/src/app/qgisapp.cpp
@@ -204,6 +204,7 @@ Q_GUI_EXPORT extern int qt_defaultDpiX();
 #include "qgslayertreeviewembeddedindicator.h"
 #include "qgslayertreeviewfilterindicator.h"
 #include "qgslayertreeviewmemoryindicator.h"
+#include "qgslayertreeviewnonremovableindicator.h"
 #include "qgslayout.h"
 #include "qgslayoutatlas.h"
 #include "qgslayoutcustomdrophandler.h"
@@ -3873,6 +3874,7 @@ void QgisApp::initLayerTreeView()
   new QgsLayerTreeViewFilterIndicatorProvider( mLayerTreeView );  // gets parented to the layer view
   new QgsLayerTreeViewEmbeddedIndicatorProvider( mLayerTreeView );  // gets parented to the layer view
   new QgsLayerTreeViewMemoryIndicatorProvider( mLayerTreeView );  // gets parented to the layer view
+  new QgsLayerTreeViewNonRemovableIndicatorProvider( mLayerTreeView );  // gets parented to the layer view
 
   setupLayerTreeViewFromSettings();
 

diff --git a/src/app/qgslayertreeviewnonremovableindicator.cpp b/src/app/qgslayertreeviewnonremovableindicator.cpp
@@ -0,0 +1,165 @@
+/***************************************************************************
+  qgslayertreeviewnonremovableindicator.cpp
+  --------------------------------------
+  Date                 : Sep 2018
+  Copyright            : (C) 2018 by Martin Dobias
+  Email                : wonder dot sk at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgslayertreeviewnonremovableindicator.h"
+
+#include "qgslayertree.h"
+#include "qgslayertreemodel.h"
+#include "qgslayertreeview.h"
+
+
+QgsLayerTreeViewNonRemovableIndicatorProvider::QgsLayerTreeViewNonRemovableIndicatorProvider( QgsLayerTreeView *view )
+  : QObject( view )
+  , mLayerTreeView( view )
+{
+  mIcon = QgsApplication::getThemeIcon( QStringLiteral( "/lockedGray.svg" ) );
+
+  QgsLayerTree *tree = mLayerTreeView->layerTreeModel()->rootGroup();
+  onAddedChildren( tree, 0, tree->children().count() - 1 );
+
+  connect( tree, &QgsLayerTree::addedChildren, this, &QgsLayerTreeViewNonRemovableIndicatorProvider::onAddedChildren );
+  connect( tree, &QgsLayerTree::willRemoveChildren, this, &QgsLayerTreeViewNonRemovableIndicatorProvider::onWillRemoveChildren );
+}
+
+void QgsLayerTreeViewNonRemovableIndicatorProvider::onAddedChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo )
+{
+  // recursively connect to providers' dataChanged() signal
+
+  QList<QgsLayerTreeNode *> children = node->children();
+  for ( int i = indexFrom; i <= indexTo; ++i )
+  {
+    QgsLayerTreeNode *childNode = children[i];
+
+    if ( QgsLayerTree::isGroup( childNode ) )
+    {
+      onAddedChildren( childNode, 0, childNode->children().count() - 1 );
+    }
+    else if ( QgsLayerTree::isLayer( childNode ) )
+    {
+      QgsLayerTreeLayer *childLayerNode = QgsLayerTree::toLayer( childNode );
+      if ( QgsMapLayer *layer = childLayerNode->layer() )
+      {
+        connect( layer, &QgsMapLayer::flagsChanged, this, &QgsLayerTreeViewNonRemovableIndicatorProvider::onFlagsChanged );
+        addOrRemoveIndicator( childLayerNode, layer );
+      }
+      else if ( !childLayerNode->layer() )
+      {
+        // wait for layer to be loaded (e.g. when loading project, first the tree is loaded, afterwards the references to layers are resolved)
+        connect( childLayerNode, &QgsLayerTreeLayer::layerLoaded, this, &QgsLayerTreeViewNonRemovableIndicatorProvider::onLayerLoaded );
+      }
+    }
+  }
+}
+
+
+void QgsLayerTreeViewNonRemovableIndicatorProvider::onWillRemoveChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo )
+{
+  // recursively disconnect from providers' dataChanged() signal
+
+  QList<QgsLayerTreeNode *> children = node->children();
+  for ( int i = indexFrom; i <= indexTo; ++i )
+  {
+    QgsLayerTreeNode *childNode = children[i];
+
+    if ( QgsLayerTree::isGroup( childNode ) )
+    {
+      onWillRemoveChildren( childNode, 0, childNode->children().count() - 1 );
+    }
+    else if ( QgsLayerTree::isLayer( childNode ) )
+    {
+      QgsLayerTreeLayer *childLayerNode = QgsLayerTree::toLayer( childNode );
+      if ( childLayerNode->layer() )
+        disconnect( childLayerNode->layer(), &QgsMapLayer::flagsChanged, this, &QgsLayerTreeViewNonRemovableIndicatorProvider::onFlagsChanged );
+    }
+  }
+}
+
+
+void QgsLayerTreeViewNonRemovableIndicatorProvider::onLayerLoaded()
+{
+  QgsLayerTreeLayer *nodeLayer = qobject_cast<QgsLayerTreeLayer *>( sender() );
+  if ( !nodeLayer )
+    return;
+
+  if ( QgsMapLayer *layer = nodeLayer->layer() )
+  {
+    connect( layer, &QgsMapLayer::flagsChanged, this, &QgsLayerTreeViewNonRemovableIndicatorProvider::onFlagsChanged );
+    addOrRemoveIndicator( nodeLayer, layer );
+  }
+}
+
+void QgsLayerTreeViewNonRemovableIndicatorProvider::onFlagsChanged()
+{
+  QgsMapLayer *layer = qobject_cast<QgsMapLayer *>( sender() );
+  if ( !layer )
+    return;
+
+  // walk the tree and find layer node that needs to be updated
+  const QList<QgsLayerTreeLayer *> layerNodes = mLayerTreeView->layerTreeModel()->rootGroup()->findLayers();
+  for ( QgsLayerTreeLayer *node : layerNodes )
+  {
+    if ( node->layer() && node->layer() == layer )
+    {
+      addOrRemoveIndicator( node, layer );
+      break;
+    }
+  }
+}
+
+
+std::unique_ptr<QgsLayerTreeViewIndicator> QgsLayerTreeViewNonRemovableIndicatorProvider::newIndicator()
+{
+  std::unique_ptr< QgsLayerTreeViewIndicator > indicator = qgis::make_unique< QgsLayerTreeViewIndicator >( this );
+  indicator->setIcon( mIcon );
+  indicator->setToolTip( tr( "Layer required by the project" ) );
+  mIndicators.insert( indicator.get() );
+  return indicator;
+}
+
+void QgsLayerTreeViewNonRemovableIndicatorProvider::addOrRemoveIndicator( QgsLayerTreeNode *node, QgsMapLayer *layer )
+{
+  bool removable = layer->flags() & QgsMapLayer::Removable;
+  if ( !removable )
+  {
+    const QList<QgsLayerTreeViewIndicator *> nodeIndicators = mLayerTreeView->indicators( node );
+
+    // maybe the indicator exists already
+    for ( QgsLayerTreeViewIndicator *indicator : nodeIndicators )
+    {
+      if ( mIndicators.contains( indicator ) )
+        return;
+    }
+
+    // it does not exist: need to create a new one
+    mLayerTreeView->addIndicator( node, newIndicator().release() );
+  }
+  else
+  {
+    const QList<QgsLayerTreeViewIndicator *> nodeIndicators = mLayerTreeView->indicators( node );
+
+    // there may be existing indicator we need to get rid of
+    for ( QgsLayerTreeViewIndicator *indicator : nodeIndicators )
+    {
+      if ( mIndicators.contains( indicator ) )
+      {
+        mLayerTreeView->removeIndicator( node, indicator );
+        indicator->deleteLater();
+        return;
+      }
+    }
+
+    // no indicator was there before, nothing to do
+  }
+}
diff --git a/src/app/qgslayertreeviewnonremovableindicator.h b/src/app/qgslayertreeviewnonremovableindicator.h
@@ -0,0 +1,54 @@
+/***************************************************************************
+  qgslayertreeviewnonremovableindicator.h
+  --------------------------------------
+  Date                 : Sep 2018
+  Copyright            : (C) 2018 by Martin Dobias
+  Email                : wonder dot sk at gmail dot com
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSLAYERTREEVIEWNONREMOVABLEINDICATOR_H
+#define QGSLAYERTREEVIEWNONREMOVABLEINDICATOR_H
+
+#include "qgslayertreeviewindicator.h"
+
+#include <QSet>
+#include <memory>
+
+class QgsLayerTreeNode;
+class QgsLayerTreeView;
+class QgsMapLayer;
+
+class QgsLayerTreeViewNonRemovableIndicatorProvider : public QObject
+{
+    Q_OBJECT
+  public:
+    explicit QgsLayerTreeViewNonRemovableIndicatorProvider( QgsLayerTreeView *view );
+
+  private slots:
+    //! Connects to signals of layers newly added to the tree
+    void onAddedChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo );
+    //! Disconnects from layers about to be removed from the tree
+    void onWillRemoveChildren( QgsLayerTreeNode *node, int indexFrom, int indexTo );
+    //! Starts listening to layer provider's dataChanged signal
+    void onLayerLoaded();
+    void onFlagsChanged();
+
+  private:
+    std::unique_ptr< QgsLayerTreeViewIndicator > newIndicator();
+    void addOrRemoveIndicator( QgsLayerTreeNode *node, QgsMapLayer *layer );
+
+  private:
+    QgsLayerTreeView *mLayerTreeView = nullptr;
+    QIcon mIcon;
+    QSet<QgsLayerTreeViewIndicator *> mIndicators;
+};
+
+
+#endif // QGSLAYERTREEVIEWNONREMOVABLEINDICATOR_H