logic for tracking state of the project/map canvas so user can be prompted to save prior to exiting, closing, opening, or creating a new project file

git-svn-id: http://svn.osgeo.org/qgis/trunk@621 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/qgisapp.cpp

@@ -284,6 +284,8 @@ QgisApp::QgisApp(QWidget * parent, const char *name, WFlags fl):QgisAppBase(pare
   delete mySplash;
   QString plib = PLUGINS;
   std::cout << "Plugins are installed in " << plib << std::endl;
+  // set the dirty flag to false -- no changes yet
+  projectIsDirty = false;
 }
 
 QgisApp::~QgisApp()
@@ -352,6 +354,7 @@ void QgisApp::addLayer()
 		    lyr->setRenderer(renderer);
 		    renderer->initializeSymbology(lyr);
 		    mapCanvas->addLayer(lyr);
+        projectIsDirty = true;
 		} else {
 			QString msg = *it + " ";
 			msg += tr("is not a valid or recognized data source");
@@ -447,6 +450,7 @@ QgisApp::addRasterLayer()
     {
       // add it to the mapcanvas collection
       mapCanvas->addLayer( layer );
+      projectIsDirty = true;
     } else 
     {
       QString msg( *it + " is not a valid or recognized raster data source" );
@@ -543,6 +547,7 @@ void QgisApp::addDatabaseLayer()
         renderer->initializeSymbology(lyr);
         // add it to the mapcanvas collection
         mapCanvas->addLayer(lyr);
+        projectIsDirty = true;
       }else{
         std::cerr << *it << " is an invalid layer - not loaded" << std::endl;
         QMessageBox::critical(this, tr("Invalid Layer"),
@@ -579,24 +584,34 @@ void QgisApp::fileExit()
 
 }
 void QgisApp::fileNew(){
-	mapCanvas->removeAll();
-	setCaption(tr("Quantum GIS -- Untitled"));
-	mapCanvas->clear();
-	mapLegend->update();
-	fullPath = "";
+  int answer= saveDirty();
+ 
+  if(answer != QMessageBox::Cancel){
+    mapCanvas->removeAll();
+    setCaption(tr("Quantum GIS -- Untitled"));
+    mapCanvas->clear();
+    mapLegend->update();
+    fullPath = "";
+    projectIsDirty = false;
+  }
 }
 void QgisApp::fileOpen(){
-	mapCanvas->freeze(true);
-	QgsProjectIo *pio = new QgsProjectIo(mapCanvas, QgsProjectIo::OPEN, this);
-	
-	if(pio->read()){
-		setCaption(tr("Quantum GIS --") +" " + pio->baseName());
-		fullPath = pio->fullPathName();
-		}
-	delete pio;
-	
-	mapLegend->update();
-	mapCanvas->freeze(false);
+  int answer= saveDirty();
+ 
+  if(answer != QMessageBox::Cancel){
+    mapCanvas->freeze(true);
+    QgsProjectIo *pio = new QgsProjectIo(mapCanvas, QgsProjectIo::OPEN, this);
+    
+    if(pio->read()){
+      setCaption(tr("Quantum GIS --") +" " + pio->baseName());
+      fullPath = pio->fullPathName();
+      }
+    delete pio;
+    
+    mapLegend->update();
+    mapCanvas->freeze(false);
+    projectIsDirty = false;
+  }
 }
 void QgisApp::fileSave(){
 	QgsProjectIo *pio = new QgsProjectIo(mapCanvas, QgsProjectIo::SAVE);
@@ -606,6 +621,7 @@ void QgisApp::fileSave(){
 		statusBar()->message(tr("Saved map to:") +" "  + pio->fullPathName());
 	}
 	delete pio;
+  projectIsDirty = false;
 }
 
 void QgisApp::fileSaveAs(){
@@ -615,6 +631,7 @@ void QgisApp::fileSaveAs(){
 		statusBar()->message(tr("Saved map to:") + " " + pio->fullPathName());
 	}
 	delete pio;	
+   projectIsDirty = false;
 }
 
 void QgisApp::exportMapServer(){
@@ -1401,6 +1418,7 @@ void QgisApp::addVectorLayer(QString vectorLayerPath, QString baseName, QString
 			renderer->initializeSymbology(lyr);
 			// add it to the mapcanvas collection
 			mapCanvas->addLayer(lyr);
+      projectIsDirty = true;
 			//qWarning("incrementing iterator");
 		/*! \todo Need legend scrollview and legenditem classes */
 		mapLegend->update();
@@ -1416,3 +1434,19 @@ void QgisApp::addVectorLayer(QString vectorLayerPath, QString baseName, QString
 	mapCanvas->render2();
 	QApplication::restoreOverrideCursor();
 }
+int QgisApp::saveDirty(){
+   int answer = 0;
+   mapCanvas->freeze(true);
+   if((projectIsDirty || mapCanvas->isDirty()) && mapCanvas->layerCount() > 0){
+    // prompt user to save
+    answer =  QMessageBox::information(this, "Save?","Do you want to save the current project?",
+    QMessageBox::Yes | QMessageBox::Default,
+    QMessageBox::No,
+    QMessageBox::Cancel | QMessageBox::Escape);
+    if(answer == QMessageBox::Yes){
+      fileSave();
+    }
+  }
+  mapCanvas->freeze(false);
+  return answer;
+}

src/qgisapp.h

@@ -93,7 +93,8 @@ class QgisApp:public QgisAppBase
 	void about();
 	//! activates the selection tool
 	void select();
-
+  //! check to see if file is dirty and if so, prompt the user th save it
+  int saveDirty();
 	private slots:				
 		//! Slot to show the map coordinate position of the mouse cursor
 	void showMouseCoordinate(QgsPoint &);
@@ -167,6 +168,10 @@ class QgisApp:public QgisAppBase
 	QString versionMessage;
 	friend class QgisIface;
   QgsProviderRegistry *providerRegistry;
+  /** Flag to track whether the user should be prompted to save the project
+  * before opening/creating a new one or exiting the application
+  */
+  bool projectIsDirty;
 };
 
 #endif

src/qgsmapcanvas.cpp

@@ -72,6 +72,9 @@ QgsLegend * QgsMapCanvas::getLegend(){
 void QgsMapCanvas::setDirty(bool _dirty){
 	dirty = _dirty;
 }
+bool QgsMapCanvas::isDirty(){
+  return dirty;
+}
 void QgsMapCanvas::addLayer(QgsMapLayerInterface * lyr){
 	// add a maplayer interface to a layer type defined in a plugin
 	
@@ -312,6 +315,7 @@ void QgsMapCanvas::zoomFullExtent()
 	currentExtent = fullExtent;
 	clear();
 	render2();
+  dirty = true;
 }
 
 void QgsMapCanvas::zoomPreviousExtent()
@@ -322,6 +326,7 @@ void QgsMapCanvas::zoomPreviousExtent()
 		previousExtent = tempRect;
 		clear();
 		render2();
+    dirty = true;
 	}
 }
 
@@ -365,6 +370,7 @@ void QgsMapCanvas::zoomToSelected()
 	    return;
 	}
     }
+    dirty = true;
 }
 
 void QgsMapCanvas::mousePressEvent(QMouseEvent * e)
@@ -413,6 +419,7 @@ void QgsMapCanvas::mouseReleaseEvent(QMouseEvent * e)
 			  currentExtent.normalize();
 			  clear();
 			  render2();
+        dirty = true;
 			  break;
 		  case QGis::ZoomOut:
 			  {
@@ -454,6 +461,7 @@ void QgsMapCanvas::mouseReleaseEvent(QMouseEvent * e)
 				  std::cout << "Center of currentExtent after scaling is " << currentExtent.center() << std::endl;
 				  clear();
 				  render2();
+          dirty = true;
 			  }
 			  break;
 
@@ -485,6 +493,7 @@ void QgsMapCanvas::mouseReleaseEvent(QMouseEvent * e)
 			  }
 			  clear();
 			  render2();
+        dirty = true;
 		  }
 			  break;
 
@@ -700,6 +709,7 @@ void QgsMapCanvas::remove(QString key)
 	layers = newLayers;
 	delete l;
 	zOrder.remove(key);
+  dirty = true;
 }
 void QgsMapCanvas::removeAll(){
 	layers.clear();

src/qgsmapcanvas.h

@@ -99,6 +99,8 @@ class QgsMapCanvas:public QWidget
     void removeAll();
     //! Flag the canvas as dirty and needed a refresh
     void setDirty(bool _dirty);
+    //! Return the state of the canvas (dirty or not)
+    bool isDirty();
     //! Declare the legend class as a friend of the map canvas
     friend class QgsLegend;
     public slots:

src/qgsprojectio.cpp

@@ -12,7 +12,7 @@
  *   (at your option) any later version.                                   *
  *                                                                         *
  ***************************************************************************/
-/* qgsprojectio.cpp,v 1.20 2004/01/27 07:56:13 mhugent Exp */
+/* qgsprojectio.cpp,v 1.21 2004/01/28 05:55:27 gsherman Exp */
 #include <iostream>
 #include <fstream>
 #include <qfiledialog.h>
@@ -481,10 +481,10 @@ if(action == SAVE && fullPath.isEmpty()){
 	}
 switch(action){
 	case OPEN:
-	fullPath = QFileDialog::getOpenFileName("./", QObject::tr("QGis files (*.qgs)"), 0,  0, QObject::tr("Choose a file to open") );
+	fullPath = QFileDialog::getOpenFileName("./", QObject::tr("QGis files (*.qgs)"), 0,  0, QObject::tr("Choose a QGIS project file to open") );
 	break;
 	case SAVEAS:
-		fullPath = QFileDialog::getSaveFileName("./", QObject::tr("QGis files (*.qgs)"), 0,  0, QObject::tr("Choose a filename  to save") );
+		fullPath = QFileDialog::getSaveFileName("./", QObject::tr("QGis files (*.qgs)"), 0,  0, QObject::tr("Choose a filename to save") );
 	break;
 	}
 	return fullPath;