[ui] display information messages to the user

This commit add some messages to the user :
- An instruction message
- If an empty json file is saved.
- If there is no property to display (if the json file loaded is empty for exemple)

ApplicationComponents/SaveAndLoadLidarState/lqLidarStateDialog.cxx

@@ -7,10 +7,12 @@
 
 //-----------------------------------------------------------------------------
 lqLidarStateDialog::lqLidarStateDialog(QWidget *parent,
-                                       std::vector<propertyInfo>& propertiesVector) :
+                                       std::vector<propertyInfo>& propertiesVector,
+                                       const std::string& instruction) :
   QDialog(parent)
 {
   this->properties = propertiesVector;
+  this->instructions = QString(instruction.c_str());
 
   QVBoxLayout* vbox = new QVBoxLayout;
 
@@ -26,6 +28,22 @@ lqLidarStateDialog::lqLidarStateDialog(QWidget *parent,
 //-----------------------------------------------------------------------------
 void lqLidarStateDialog::CreateDialog(QVBoxLayout *vbox)
 {
+  // Display an information message if there is no property to display
+  if(this->properties.empty())
+  {
+    QLabel * label =  new QLabel(QString("No property available"));
+    vbox->addWidget(label, 0, Qt::AlignCenter);
+    return;
+  }
+
+  // Display a message to give a tip to the user :
+  if(!this->instructions.isEmpty())
+  {
+    QLabel * label =  new QLabel(this->instructions);
+    label->setStyleSheet("font: italic;font-size: 12px ; color: grey");
+    vbox->addWidget(label, 0, Qt::AlignLeft);
+  }
+
   for(unsigned int i = 0; i < this->properties.size(); i++)
   {
     propertyInfo currentProperty = this->properties[i];

ApplicationComponents/SaveAndLoadLidarState/lqLidarStateDialog.h

@@ -63,13 +63,17 @@ class lqLidarStateDialog : public QDialog
   Q_OBJECT
 
 public:
-  explicit lqLidarStateDialog(QWidget *parent, std::vector<propertyInfo>& propertiesVector);
+  explicit lqLidarStateDialog(QWidget *parent,
+                              std::vector<propertyInfo>& propertiesVector,
+                              const std::string& instruction = "");
 
   ~lqLidarStateDialog(){}
 
   void CreateDialog(QVBoxLayout * vbox);
 
   std::vector<propertyInfo> properties;
+
+  QString instructions;
 };
 #endif // LQLIDARSTATEDIALOG_H
 

ApplicationComponents/SaveAndLoadLidarState/lqLoadLidarStateReaction.cxx

@@ -80,7 +80,7 @@ void lqLoadLidarStateReaction::onTriggered()
     return;
   }
 
-  lqLidarStateDialog dialog(nullptr, propertyInfo);
+  lqLidarStateDialog dialog(nullptr, propertyInfo, "Please select the parameters to load");
   if(dialog.exec())
   {
     for(const auto & currentProp : dialog.properties)

ApplicationComponents/SaveAndLoadLidarState/lqSaveLidarStateReaction.cxx

@@ -70,7 +70,7 @@ void lqSaveLidarStateReaction::onTriggered()
   std::vector<propertyInfo> propertiesInfo;
   constructPropertiesInfo(lidarProxy, propertiesInfo);
 
-  lqLidarStateDialog dialog(nullptr, propertiesInfo);
+  lqLidarStateDialog dialog(nullptr, propertiesInfo, "Please select the parameters to save");
   if(dialog.exec())
   {
     Json::StyledStreamWriter writer;
@@ -108,6 +108,10 @@ void lqSaveLidarStateReaction::onTriggered()
         }
       }
     }
+    if(data.empty())
+    {
+      QMessageBox::information(nullptr, QObject::tr(""), QObject::tr("Saved json file is empty (no parameter selected)"));
+    }
     writer.write(configFile, data);
   }