An item can be added to the model with accepting the NewItemDialog.

Dialogs/newitemdialog.cpp

@@ -1,6 +1,8 @@
 #include "newitemdialog.h"
 
 #include <QGridLayout>
+#include <QJsonArray>
+#include <QJsonObject>
 #include <QLabel>
 #include <QLineEdit>
 #include <QSpinBox>
@@ -58,3 +60,21 @@ void NewItemDialog::createContent() {
 
   m_outerLayout->insertWidget(0, m_contentContainer);
 }
+
+void NewItemDialog::accept() {
+  QJsonObject itemObject;
+  itemObject.insert("Name", m_nameEdit->text());
+  itemObject.insert("Description", m_descriptionEdit->text());
+  itemObject.insert("Info", m_infoEdit->text());
+  itemObject.insert("Amount", m_amountBox->value());
+  itemObject.insert("Factor", m_factorBox->value());
+
+  QJsonDocument jsonDoc;
+  QJsonArray itemArray;
+  itemArray.append(itemObject);
+  jsonDoc.setArray(itemArray);
+  emit addItems(jsonDoc.toJson(QJsonDocument::Compact));
+
+  // resetContent();
+  AbstractDialog::accept();
+}

Dialogs/newitemdialog.h

@@ -3,15 +3,25 @@
 
 #include "abstractdialog.h"
 
+class QDoubleSpinBox;
 class QLineEdit;
 class QSpinBox;
 class QLabel;
 class NewItemDialog : public AbstractDialog {
+  Q_OBJECT
+
  public:
   NewItemDialog(QWidget* parent = nullptr);
 
   void createContent() override;
 
+ signals:
+  void addItems(const QByteArray& jsonDoc);
+
+ public slots:
+  void accept() override;
+  // void reject() override;
+
  private:
   QLabel* m_nameLabel   = nullptr;
   QLineEdit* m_nameEdit = nullptr;