Add recordpanel beside datagrid

pglab/crud/RecordPanel.cpp

@@ -0,0 +1,268 @@
+#include "RecordPanel.h"
+#include "CustomDataRole.h"
+#include "Pgsql_oids.h"
+#include <QEvent>
+#include <QFont>
+#include <QFontDatabase>
+#include <QFormLayout>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QLineEdit>
+#include <QPlainTextEdit>
+#include <QToolButton>
+#include <QVBoxLayout>
+
+namespace {
+
+constexpr int CollapsedTextLines = 2;
+constexpr int ExpandedTextLines = 10;
+
+bool isLongTextType(Oid oid)
+{
+	switch (oid) {
+		case Pgsql::text_oid:
+		case Pgsql::varchar_oid:
+		case Pgsql::bpchar_oid:
+		case Pgsql::json_oid:
+		case Pgsql::jsonb_oid:
+		case Pgsql::xml_oid:
+			return true;
+		default:
+			return false;
+	}
+}
+
+int textEditHeight(const QPlainTextEdit *edit, int lines)
+{
+	return edit->fontMetrics().lineSpacing() * lines + 2 * edit->frameWidth() + 6;
+}
+
+QString editorText(const QWidget *editor)
+{
+	if (auto line = qobject_cast<const QLineEdit *>(editor))
+		return line->text();
+	if (auto plain = qobject_cast<const QPlainTextEdit *>(editor))
+		return plain->toPlainText();
+	return {};
+}
+
+} // namespace
+
+RecordPanel::RecordPanel(QWidget *parent)
+	: QScrollArea(parent)
+{
+	setWidgetResizable(true);
+}
+
+void RecordPanel::setModel(QAbstractItemModel *model)
+{
+	if (m_model)
+		m_model->disconnect(this);
+
+	m_model = model;
+	if (m_model) {
+		connect(m_model, &QAbstractItemModel::dataChanged, this, &RecordPanel::refresh);
+		connect(m_model, &QAbstractItemModel::layoutChanged, this, &RecordPanel::refresh);
+		connect(m_model, &QAbstractItemModel::rowsInserted, this, &RecordPanel::refresh);
+		connect(m_model, &QAbstractItemModel::rowsRemoved, this, &RecordPanel::refresh);
+		connect(m_model, &QAbstractItemModel::modelReset, this, &RecordPanel::onModelReset);
+	}
+	onModelReset();
+}
+
+void RecordPanel::setFirstDataColumn(int column)
+{
+	m_firstDataColumn = column;
+	clearFields();
+	refresh();
+}
+
+void RecordPanel::setCurrentRow(int row)
+{
+	if (m_model && row >= 0 && row < m_model->rowCount())
+		m_rowIndex = QPersistentModelIndex(m_model->index(row, 0));
+	else
+		m_rowIndex = QPersistentModelIndex();
+	refresh();
+}
+
+void RecordPanel::onModelReset()
+{
+	m_rowIndex = QPersistentModelIndex();
+	refresh();
+}
+
+void RecordPanel::refresh()
+{
+	if (!m_model || !m_rowIndex.isValid()) {
+		clearFields();
+		return;
+	}
+
+	int columns = m_model->columnCount() - m_firstDataColumn;
+	if (columns < 0)
+		columns = 0;
+	if (m_fields.size() != static_cast<size_t>(columns))
+		rebuild();
+
+	for (auto &field : m_fields) {
+		QModelIndex index = m_model->index(m_rowIndex.row(), field.column);
+		bool editable = m_model->flags(index).testFlag(Qt::ItemIsEditable);
+		QVariant value = index.data(Qt::EditRole);
+		QString text;
+		if (value.isValid() && !value.isNull()) {
+			text = value.toString();
+			// An empty string is shown as '' so it can be told apart from NULL, the placeholder shows NULL
+			if (text.isEmpty())
+				text = QStringLiteral("''");
+		}
+		showValue(field, text, editable);
+	}
+}
+
+void RecordPanel::clearFields()
+{
+	m_fields.clear();
+	if (QWidget *old = takeWidget())
+		old->deleteLater();
+}
+
+void RecordPanel::rebuild()
+{
+	clearFields();
+
+	auto content = new QWidget;
+	auto layout = new QFormLayout(content);
+	layout->setFieldGrowthPolicy(QFormLayout::AllNonFixedFieldsGrow);
+
+	int row = m_rowIndex.row();
+	for (int column = m_firstDataColumn; column < m_model->columnCount(); ++column) {
+		QString header = m_model->headerData(column, Qt::Horizontal, Qt::DisplayRole).toString();
+		int newline = header.indexOf('\n');
+		QString name = newline < 0 ? header : header.left(newline);
+		QString typeName = newline < 0 ? QString() : header.mid(newline + 1);
+
+		auto caption = new QWidget(content);
+		auto captionLayout = new QVBoxLayout(caption);
+		captionLayout->setContentsMargins(0, 0, 0, 0);
+		auto nameLabel = new QLabel(name, caption);
+		QFont nameFont = nameLabel->font();
+		nameFont.setBold(true);
+		nameLabel->setFont(nameFont);
+		auto typeLabel = new QLabel(typeName, caption);
+		captionLayout->addWidget(nameLabel);
+		captionLayout->addWidget(typeLabel);
+
+		Oid oid = m_model->index(row, column).data(CustomDataTypeRole).toUInt();
+		FieldRow field;
+		field.column = column;
+		QWidget *fieldWidget = nullptr;
+
+		if (isLongTextType(oid)) {
+			auto container = new QWidget(content);
+			auto containerLayout = new QVBoxLayout(container);
+			containerLayout->setContentsMargins(0, 0, 0, 0);
+
+			auto edit = new QPlainTextEdit(container);
+			edit->setFont(QFontDatabase::systemFont(QFontDatabase::FixedFont));
+			edit->setPlaceholderText(tr("null"));
+			edit->setFixedHeight(textEditHeight(edit, CollapsedTextLines));
+			edit->installEventFilter(this);
+
+			auto expand = new QToolButton(container);
+			expand->setCheckable(true);
+			expand->setArrowType(Qt::DownArrow);
+			expand->setToolTip(tr("Expand or collapse the value"));
+			connect(expand, &QToolButton::toggled, edit, [edit, expand](bool expanded) {
+				edit->setFixedHeight(textEditHeight(edit, expanded ? ExpandedTextLines : CollapsedTextLines));
+				expand->setArrowType(expanded ? Qt::UpArrow : Qt::DownArrow);
+			});
+
+			auto buttonRow = new QHBoxLayout;
+			buttonRow->addStretch();
+			buttonRow->addWidget(expand);
+			containerLayout->addWidget(edit);
+			containerLayout->addLayout(buttonRow);
+
+			field.editor = edit;
+			field.expandButton = expand;
+			fieldWidget = container;
+		}
+		else {
+			auto edit = new QLineEdit(content);
+			edit->setPlaceholderText(tr("null"));
+			connect(edit, &QLineEdit::editingFinished, this, [this, edit]() { commitEditor(edit); });
+
+			field.editor = edit;
+			fieldWidget = edit;
+		}
+
+		layout->addRow(caption, fieldWidget);
+		m_fields.push_back(field);
+	}
+
+	setWidget(content);
+}
+
+void RecordPanel::showValue(FieldRow &field, const QString &text, bool editable)
+{
+	QWidget *editor = field.editor;
+	if (auto line = qobject_cast<QLineEdit *>(editor))
+		line->setReadOnly(!editable);
+	else if (auto plain = qobject_cast<QPlainTextEdit *>(editor))
+		plain->setReadOnly(!editable);
+
+	// Do not replace the text while the user is typing in it
+	if (editor->hasFocus())
+		return;
+
+	if (auto line = qobject_cast<QLineEdit *>(editor))
+		line->setText(text);
+	else if (auto plain = qobject_cast<QPlainTextEdit *>(editor))
+		plain->setPlainText(text);
+	field.original = text;
+}
+
+void RecordPanel::commitEditor(QWidget *editor)
+{
+	if (m_updating || !m_model || !m_rowIndex.isValid())
+		return;
+
+	FieldRow *field = findField(editor);
+	if (!field)
+		return;
+
+	QString text = editorText(editor);
+	if (text == field->original)
+		return;
+
+	QModelIndex index = m_model->index(m_rowIndex.row(), field->column);
+	if (!m_model->flags(index).testFlag(Qt::ItemIsEditable))
+		return;
+
+	m_updating = true;
+	m_model->setData(index, text, Qt::EditRole);
+	m_updating = false;
+
+	// The model may have rebuilt the fields while storing the value, so look the field up again
+	if (FieldRow *updated = findField(editor))
+		updated->original = text;
+}
+
+RecordPanel::FieldRow *RecordPanel::findField(QWidget *editor)
+{
+	for (auto &field : m_fields) {
+		if (field.editor == editor)
+			return &field;
+	}
+	return nullptr;
+}
+
+bool RecordPanel::eventFilter(QObject *watched, QEvent *event)
+{
+	if (event->type() == QEvent::FocusOut) {
+		if (auto edit = qobject_cast<QPlainTextEdit *>(watched))
+			commitEditor(edit);
+	}
+	return QScrollArea::eventFilter(watched, event);
+}