informationwindow.cpp Example File

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 #include "informationwindow.h"

 InformationWindow::InformationWindow(int id, QSqlRelationalTableModel *items,
                                      QWidget *parent)
     : QDialog(parent)
 {
     QLabel *itemLabel = new QLabel(tr("Item: "));
     QLabel *descriptionLabel = new QLabel(tr("Description: "));
     QLabel *imageFileLabel = new QLabel(tr("Image file: "));

     createButtons();

     itemText = new QLabel;
     descriptionEditor = new QTextEdit;

     imageFileEditor = new QComboBox;
     imageFileEditor->setModel(items->relationModel(1));
     imageFileEditor->setModelColumn(items->relationModel(1)->fieldIndex("file"));

     mapper = new QDataWidgetMapper(this);
     mapper->setModel(items);
     mapper->setSubmitPolicy(QDataWidgetMapper::ManualSubmit);
     mapper->setItemDelegate(new QSqlRelationalDelegate(mapper));
     mapper->addMapping(imageFileEditor, 1);
     mapper->addMapping(itemText, 2, "text");
     mapper->addMapping(descriptionEditor, 3);
     mapper->setCurrentIndex(id);

     connect(descriptionEditor, &QTextEdit::textChanged, [=]() {
         enableButtons();
     });
     connect(imageFileEditor, QOverload<int>::of(&QComboBox::currentIndexChanged), [=]() {
         enableButtons();
     });

     QFormLayout *formLayout = new QFormLayout;
     formLayout->addRow(itemLabel, itemText);
     formLayout->addRow(imageFileLabel, imageFileEditor);
     formLayout->addRow(descriptionLabel, descriptionEditor);

     QVBoxLayout *layout = new QVBoxLayout;
     layout->addLayout(formLayout);
     layout->addWidget(buttonBox);
     setLayout(layout);

     itemId = id;
     displayedImage = imageFileEditor->currentText();

     setWindowFlags(Qt::Window);
     enableButtons(false);
     setWindowTitle(itemText->text());
 }

 int InformationWindow::id() const
 {
     return itemId;
 }

 void InformationWindow::revert()
 {
     mapper->revert();
     enableButtons(false);
 }

 void InformationWindow::submit()
 {
     QString newImage(imageFileEditor->currentText());

     if (displayedImage != newImage) {
         displayedImage = newImage;
         emit imageChanged(itemId, newImage);
     }

     mapper->submit();
     mapper->setCurrentIndex(itemId);

     enableButtons(false);
 }

 void InformationWindow::createButtons()
 {
     closeButton = new QPushButton(tr("&Close"));
     revertButton = new QPushButton(tr("&Revert"));
     submitButton = new QPushButton(tr("&Submit"));

     closeButton->setDefault(true);

     connect(closeButton, &QPushButton::clicked, this, &InformationWindow::close);
     connect(revertButton, &QPushButton::clicked, this, &InformationWindow::revert);
     connect(submitButton, &QPushButton::clicked, this, &InformationWindow::submit);

     buttonBox = new QDialogButtonBox(this);
     buttonBox->addButton(submitButton, QDialogButtonBox::AcceptRole);
     buttonBox->addButton(revertButton, QDialogButtonBox::ResetRole);
     buttonBox->addButton(closeButton, QDialogButtonBox::RejectRole);
 }

 void InformationWindow::enableButtons(bool enable)
 {
     revertButton->setEnabled(enable);
     submitButton->setEnabled(enable);
 }