[bugfix][backport] Browser shared model

Backport of master PR 5164

Author: elpaso

src/app/qgisapp.cpp

@@ -116,6 +116,7 @@
 #include "qgsauthsslerrorsdialog.h"
 #endif
 #include "qgsbookmarks.h"
+#include "qgsbrowsermodel.h"
 #include "qgsbrowserdockwidget.h"
 #include "qgsadvanceddigitizingdockwidget.h"
 #include "qgsclipboard.h"
@@ -803,12 +804,13 @@ QgisApp::QgisApp( QSplashScreen *splash, bool restorePlugins, bool skipVersionCh
   mSnappingDialog->setObjectName( "SnappingOption" );
   endProfile();
 
-  mBrowserWidget = new QgsBrowserDockWidget( tr( "Browser Panel" ), this );
+  mBrowserModel = new QgsBrowserModel( this );
+  mBrowserWidget = new QgsBrowserDockWidget( tr( "Browser Panel" ), mBrowserModel, this );
   mBrowserWidget->setObjectName( "Browser" );
   addDockWidget( Qt::LeftDockWidgetArea, mBrowserWidget );
   mBrowserWidget->hide();
 
-  mBrowserWidget2 = new QgsBrowserDockWidget( tr( "Browser Panel (2)" ), this );
+  mBrowserWidget2 = new QgsBrowserDockWidget( tr( "Browser Panel (2)" ), mBrowserModel, this );
   mBrowserWidget2->setObjectName( "Browser2" );
   addDockWidget( Qt::LeftDockWidgetArea, mBrowserWidget2 );
   mBrowserWidget2->hide();
@@ -1147,6 +1149,7 @@ QgisApp::QgisApp()
     , mPythonUtils( nullptr )
     , mUndoWidget( nullptr )
     , mUndoDock( nullptr )
+    , mBrowserModel( nullptr )
     , mBrowserWidget( nullptr )
     , mBrowserWidget2( nullptr )
     , mAdvancedDigitizingDockWidget( nullptr )

src/app/qgisapp.h

@@ -82,6 +82,7 @@ class QNetworkProxy;
 class QAuthenticator;
 
 class QgsBrowserDockWidget;
+class QgsBrowserModel;
 class QgsAdvancedDigitizingDockWidget;
 class QgsSnappingDialog;
 class QgsGPSInformationWidget;
@@ -1724,6 +1725,7 @@ class APP_EXPORT QgisApp : public QMainWindow, private Ui::MainWindow
     QgsUndoWidget *mUndoWidget;
     QgsDockWidget *mUndoDock;
 
+    QgsBrowserModel *mBrowserModel;
     QgsBrowserDockWidget *mBrowserWidget;
     QgsBrowserDockWidget *mBrowserWidget2;
 

src/app/qgsbrowserdockwidget.cpp

@@ -261,12 +261,30 @@ void QgsBrowserPropertiesDialog::setItem( QgsDataItem* item )
   setWindowTitle( item->type() == QgsDataItem::Layer ? tr( "Layer Properties" ) : tr( "Directory Properties" ) );
 }
 
+
+QgsBrowserDockWidget::QgsBrowserDockWidget( const QString& name, QgsBrowserModel *model, QWidget * parent )
+    : QgsDockWidget( parent )
+    , mModel( model )
+    , mProxyModel( nullptr )
+    , mPropertiesWidgetEnabled( false )
+    , mPropertiesWidgetHeight( 0 )
+{
+  init( name );
+}
+
+
 QgsBrowserDockWidget::QgsBrowserDockWidget( const QString& name, QWidget * parent )
     : QgsDockWidget( parent )
     , mModel( nullptr )
     , mProxyModel( nullptr )
     , mPropertiesWidgetEnabled( false )
     , mPropertiesWidgetHeight( 0 )
+{
+  init( name );
+}
+
+
+void QgsBrowserDockWidget::init( const QString& name )
 {
   setupUi( this );
 
@@ -324,6 +342,7 @@ QgsBrowserDockWidget::QgsBrowserDockWidget( const QString& name, QWidget * paren
   connect( mSplitter, SIGNAL( splitterMoved( int, int ) ), this, SLOT( splitterMoved() ) );
 }
 
+
 QgsBrowserDockWidget::~QgsBrowserDockWidget()
 {
   QSettings settings;
@@ -334,11 +353,20 @@ QgsBrowserDockWidget::~QgsBrowserDockWidget()
 
 void QgsBrowserDockWidget::showEvent( QShowEvent * e )
 {
-  // delayed initialization of the model
+
   if ( !mModel )
   {
     mModel = new QgsBrowserModel( mBrowserView );
+  }
 
+  // delayed initialization of the model
+  if ( !mModel->initialized( ) )
+  {
+    mModel->init();
+  }
+
+  if ( ! mProxyModel )
+  {
     connect( QgisApp::instance(), SIGNAL( newProject() ), mModel, SLOT( updateProjectHome() ) );
 
     mProxyModel = new QgsBrowserTreeFilterProxyModel( this );

src/app/qgsbrowserdockwidget.h

@@ -105,6 +105,7 @@ class APP_EXPORT QgsBrowserDockWidget : public QgsDockWidget, private Ui::QgsBro
     Q_OBJECT
   public:
     explicit QgsBrowserDockWidget( const QString& name, QWidget *parent = nullptr );
+    explicit QgsBrowserDockWidget( const QString& name, QgsBrowserModel *model, QWidget *parent = nullptr );
     ~QgsBrowserDockWidget();
     void addFavouriteDirectory( const QString& favDir );
 
@@ -153,6 +154,7 @@ class APP_EXPORT QgsBrowserDockWidget : public QgsDockWidget, private Ui::QgsBro
     float mPropertiesWidgetHeight;
 
   private:
+    void init( const QString& name );
 };
 
 

src/core/qgsbrowsermodel.cpp

@@ -51,10 +51,8 @@ QgsBrowserModel::QgsBrowserModel( QObject *parent )
     : QAbstractItemModel( parent )
     , mFavourites( nullptr )
     , mProjectHome( nullptr )
+    , mInitialized( false )
 {
-  connect( QgsProject::instance(), SIGNAL( readProject( const QDomDocument & ) ), this, SLOT( updateProjectHome() ) );
-  connect( QgsProject::instance(), SIGNAL( writeProject( QDomDocument & ) ), this, SLOT( updateProjectHome() ) );
-  addRootItems();
 }
 
 QgsBrowserModel::~QgsBrowserModel()
@@ -574,3 +572,14 @@ void QgsBrowserModel::hidePath( QgsDataItem *item )
     emit endRemoveRows();
   }
 }
+
+void QgsBrowserModel::init()
+{
+  if ( ! mInitialized )
+  {
+    connect( QgsProject::instance(), SIGNAL( readProject( const QDomDocument & ) ), this, SLOT( updateProjectHome() ) );
+    connect( QgsProject::instance(), SIGNAL( writeProject( QDomDocument & ) ), this, SLOT( updateProjectHome() ) );
+    addRootItems();
+    mInitialized = true;
+  }
+}

src/core/qgsbrowsermodel.h

@@ -129,6 +129,12 @@ class CORE_EXPORT QgsBrowserModel : public QAbstractItemModel
     bool canFetchMore( const QModelIndex & parent ) const override;
     void fetchMore( const QModelIndex & parent ) override;
 
+    //! Returns true if the model has been initialized
+    bool initialized( ) const { return mInitialized; }
+
+    //! Delayed initialization
+    void init();
+
   signals:
     /** Emitted when item children fetch was finished */
     void stateChanged( const QModelIndex & index, QgsDataItem::State oldState );
@@ -158,6 +164,9 @@ class CORE_EXPORT QgsBrowserModel : public QAbstractItemModel
     QVector<QgsDataItem*> mRootItems;
     QgsFavouritesItem *mFavourites;
     QgsDirectoryItem *mProjectHome;
+
+  private:
+    bool mInitialized;
 };
 
 #endif // QGSBROWSERMODEL_H