connectionwidget.cpp Example File

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 #include "connectionwidget.h"

 #include <QtWidgets>
 #include <QtSql>

 ConnectionWidget::ConnectionWidget(QWidget *parent)
     : QWidget(parent)
 {
     QVBoxLayout *layout = new QVBoxLayout(this);
     tree = new QTreeWidget(this);
     tree->setObjectName(QLatin1String("tree"));
     tree->setHeaderLabels(QStringList(tr("database")));
     tree->header()->setSectionResizeMode(QHeaderView::Stretch);
     QAction *refreshAction = new QAction(tr("Refresh"), tree);
     metaDataAction = new QAction(tr("Show Schema"), tree);
     connect(refreshAction, SIGNAL(triggered()), SLOT(refresh()));
     connect(metaDataAction, SIGNAL(triggered()), SLOT(showMetaData()));
     tree->addAction(refreshAction);
     tree->addAction(metaDataAction);
     tree->setContextMenuPolicy(Qt::ActionsContextMenu);

     layout->addWidget(tree);

     QMetaObject::connectSlotsByName(this);
 }

 ConnectionWidget::~ConnectionWidget()
 {
 }

 static QString qDBCaption(const QSqlDatabase &db)
 {
     QString nm = db.driverName();
     nm.append(QLatin1Char(':'));
     if (!db.userName().isEmpty())
         nm.append(db.userName()).append(QLatin1Char('@'));
     nm.append(db.databaseName());
     return nm;
 }

 void ConnectionWidget::refresh()
 {
     tree->clear();
     QStringList connectionNames = QSqlDatabase::connectionNames();

     bool gotActiveDb = false;
     for (int i = 0; i < connectionNames.count(); ++i) {
         QTreeWidgetItem *root = new QTreeWidgetItem(tree);
         QSqlDatabase db = QSqlDatabase::database(connectionNames.at(i), false);
         root->setText(0, qDBCaption(db));
         if (connectionNames.at(i) == activeDb) {
             gotActiveDb = true;
             setActive(root);
         }
         if (db.isOpen()) {
             QStringList tables = db.tables();
             for (int t = 0; t < tables.count(); ++t) {
                 QTreeWidgetItem *table = new QTreeWidgetItem(root);
                 table->setText(0, tables.at(t));
             }
         }
     }
     if (!gotActiveDb) {
         activeDb = connectionNames.value(0);
         setActive(tree->topLevelItem(0));
     }

     tree->doItemsLayout(); // HACK
 }

 QSqlDatabase ConnectionWidget::currentDatabase() const
 {
     return QSqlDatabase::database(activeDb);
 }

 static void qSetBold(QTreeWidgetItem *item, bool bold)
 {
     QFont font = item->font(0);
     font.setBold(bold);
     item->setFont(0, font);
 }

 void ConnectionWidget::setActive(QTreeWidgetItem *item)
 {
     for (int i = 0; i < tree->topLevelItemCount(); ++i) {
         if (tree->topLevelItem(i)->font(0).bold())
             qSetBold(tree->topLevelItem(i), false);
     }

     if (!item)
         return;

     qSetBold(item, true);
     activeDb = QSqlDatabase::connectionNames().value(tree->indexOfTopLevelItem(item));
 }

 void ConnectionWidget::on_tree_itemActivated(QTreeWidgetItem *item, int /* column */)
 {

     if (!item)
         return;

     if (!item->parent()) {
         setActive(item);
     } else {
         setActive(item->parent());
         emit tableActivated(item->text(0));
     }
 }

 void ConnectionWidget::showMetaData()
 {
     QTreeWidgetItem *cItem = tree->currentItem();
     if (!cItem || !cItem->parent())
         return;
     setActive(cItem->parent());
     emit metaDataRequested(cItem->text(0));
 }

 void ConnectionWidget::on_tree_currentItemChanged(QTreeWidgetItem *current, QTreeWidgetItem *)
 {
     metaDataAction->setEnabled(current && current->parent());
 }