Add basic drag and drop functionality

Author: u-235

gcodeworkshop/include/gcodeworkshop.h

@@ -38,6 +38,8 @@ class QClipboard;
 class QCloseEvent;
 class QComboBox;
 class QDir;
+class QDragEnterEvent;
+class QDropEvent;
 class QEvent;
 class QFileSystemModel;
 class QFileSystemWatcher;
@@ -95,6 +97,13 @@ class GCodeWorkShop : public QMainWindow
 	Document* activeDocument() const;
 	QString currentPath() const;
 	QString lastOpenedPath() const;
+	/*
+	 * To implement the opening of dragged files, we override the event handlers.
+	 * see textedit.h and textedit.cpp
+	 * see https://doc.qt.io/qt-5/dnd.html#dropping
+	 */
+	void dragEnterEvent(QDragEnterEvent* event) override;
+	void dropEvent(QDropEvent* event) override;
 
 protected:
 	Ui::GCodeWorkShop* ui;

gcodeworkshop/src/gcodereventfilter.cpp

@@ -19,11 +19,14 @@
  */
 
 #include <QChar>                    // for QChar, operator==, operator!=
+#include <QDragEnterEvent>          // for QDragEnterEvent
+#include <QDropEvent>               // for QDropEvent
 #include <QEvent>                   // for QEvent, QEvent::KeyPress, QEvent::MouseButtonDblClick, QEvent::ToolTip
 #include <QHelpEvent>               // for QHelpEvent
 #include <QKeyEvent>                // for QKeyEvent
 #include <QLatin1Char>              // for QLatin1Char
 #include <QLatin1String>            // for QLatin1String
+#include <QMimeData>                // for QMimeData
 #include <QMouseEvent>              // for QMouseEvent
 #include <QPlainTextEdit>           // for QPlainTextEdit
 #include <QRect>                    // for QRect
@@ -88,6 +91,16 @@ bool GCoderEventFilter::eventFilter(QObject* obj, QEvent* event)
 		return keyEvent(ke);
 	}
 
+	if (event->type() == QEvent::DragEnter) {
+		QDragEnterEvent* dee = dynamic_cast<QDragEnterEvent*>(event);
+		return dragEnterEvent(dee);
+	}
+
+	if (event->type() == QEvent::Drop) {
+		QDropEvent* de = dynamic_cast<QDropEvent*>(event);
+		return dropEvent(de);
+	}
+
 	return false;
 }
 
@@ -251,3 +264,13 @@ bool GCoderEventFilter::keyEvent(QKeyEvent* event)
 
 	return false;
 }
+
+bool GCoderEventFilter::dragEnterEvent(QDragEnterEvent* event)
+{
+	return event->mimeData()->hasUrls();
+}
+
+bool GCoderEventFilter::dropEvent(QDropEvent* event)
+{
+	return event->mimeData()->hasUrls();
+}

gcodeworkshop/src/gcodereventfilter.h

@@ -25,6 +25,8 @@
 #include <QRegularExpression>   // for QRegularExpression
 #include <QString>              // for QString
 
+class QDragEnterEvent;
+class QDropEvent;
 class QEvent;
 class QHelpEvent;
 class QKeyEvent;
@@ -61,6 +63,16 @@ class GCoderEventFilter : public QObject
 	bool mouseButtonDblClickEvent(QMouseEvent* event);
 	bool keyEvent(QKeyEvent* event);
 
+	/*
+	 * The QPlainTextEdit class already has a drag-n-drop mechanism, but in
+	 * the case of files, QPlainTextEdit inserts a text representation of url
+	 * into the edited document. So we add event handlers to filter such events
+	 * and handle those events in the main window.
+	 * see https://doc.qt.io/qt-5/dnd.html#dropping
+	 */
+	bool dragEnterEvent(QDragEnterEvent* event);
+	bool dropEvent(QDropEvent* event);
+
 protected:
 	QPlainTextEdit* m_textEdit;
 	QHash<QString, QString> m_tips;

gcodeworkshop/src/gcodeworkshop.cpp

@@ -36,6 +36,8 @@
 #include <QDesktopServices>     // for QDesktopServices
 #include <QDialog>              // for QDialog, QDialog::Accepted
 #include <QDir>                 // for QDir, operator|, QDir::Files, QDir::Hidden, QDir::Name, QDir::NoSymLinks
+#include <QDragEnterEvent>      // for QDragEnterEvent
+#include <QDropEvent>           // for QDropEvent
 #include <QEvent>               // for QEvent, QEvent::ToolTip
 #include <QFile>                // for QFile
 #include <QFileDialog>          // for QFileDialog, QFileDialog::DontConfirmOverwrite
@@ -60,6 +62,7 @@
 #include <QMenu>                // for QMenu
 #include <QMenuBar>             // for QMenuBar
 #include <QMessageBox>          // for QMessageBox, operator|, QMessageBox::Save, QMessageBox::Discard, QMess...
+#include <QMimeData>            // for QMimeData
 #include <QModelIndex>          // for QModelIndex
 #include <QModelIndexList>      // for QModelIndexList
 #include <QObject>              // for SIGNAL, SLOT, qobject_cast, emit
@@ -158,6 +161,7 @@ GCodeWorkShop::GCodeWorkShop(Medium* medium)
 
 	ui = new Ui::GCodeWorkShop();
 	ui->setupUi(this);
+	setAcceptDrops(true);
 
 	findToolBar = nullptr;
 	serialToolBar = nullptr;
@@ -288,6 +292,30 @@ void GCodeWorkShop::moveEvent(QMoveEvent* event)
 	QMainWindow::moveEvent(event);
 }
 
+void GCodeWorkShop::dragEnterEvent(QDragEnterEvent* event)
+{
+	if (!event->mimeData()->hasUrls()) {
+		QMainWindow::dragEnterEvent(event);
+		return;
+	}
+
+	event->acceptProposedAction();
+}
+
+void GCodeWorkShop::dropEvent(QDropEvent* event)
+{
+	if (!event->mimeData()->hasUrls()) {
+		QMainWindow::dropEvent(event);
+		return;
+	}
+
+	for (QUrl url : event->mimeData()->urls()) {
+		openFile(url.toString(QUrl::PreferLocalFile));
+	}
+
+	event->acceptProposedAction();
+}
+
 Addons::Actions* GCodeWorkShop::addonsActions()
 {
 	return m_addonsActions;