Don't block the UI when showing the statics for big columns in the

Statistics Dialog.

src/commonfrontend/matrix/MatrixView.cpp

@@ -1481,7 +1481,6 @@ void MatrixView::exportToLaTeX(const QString& path, const bool verticalHeaders,
 void MatrixView::showColumnStatistics() {
 	if (selectedColumnCount() > 0) {
 		QString dlgTitle (m_matrix->name() + " column statistics");
-		auto* dlg = new StatisticsDialog(dlgTitle);
 		QVector<Column*> columns;
 		for (int col = 0; col < m_matrix->columnCount(); ++col) {
 			if (isColumnSelected(col, false)) {
@@ -1489,7 +1488,8 @@ void MatrixView::showColumnStatistics() {
 				columns << new Column(headerString, static_cast<QVector<QVector<double>>*>(m_matrix->data())->at(col));
 			}
 		}
-		dlg->setColumns(columns);
+		auto* dlg = new StatisticsDialog(dlgTitle, columns);
+		dlg->showStatistics();
 		if (dlg->exec() == QDialog::Accepted) {
 			qDeleteAll(columns);
 			columns.clear();
@@ -1500,7 +1500,6 @@ void MatrixView::showColumnStatistics() {
 void MatrixView::showRowStatistics() {
 	if (selectedRowCount() > 0) {
 		QString dlgTitle (m_matrix->name() + " row statistics");
-		auto* dlg = new StatisticsDialog(dlgTitle);
 		QVector<Column*> columns;
 		for (int row = 0; row < m_matrix->rowCount(); ++row) {
 			if (isRowSelected(row, false)) {
@@ -1509,7 +1508,8 @@ void MatrixView::showRowStatistics() {
 				columns << new Column(headerString, m_matrix->rowCells<double>(row, 0, m_matrix->columnCount()-1));
 			}
 		}
-		dlg->setColumns(columns);
+		auto* dlg = new StatisticsDialog(dlgTitle, columns);
+		dlg->showStatistics();
 		if (dlg->exec() == QDialog::Accepted) {
 			qDeleteAll(columns);
 			columns.clear();

src/commonfrontend/spreadsheet/SpreadsheetView.cpp

@@ -83,6 +83,7 @@
 #include <QSqlError>
 #include <QSqlQuery>
 #include <QTableView>
+#include <QTimer>
 #include <QToolBar>
 #include <QTextStream>
 #include <QProcess>
@@ -2715,27 +2716,26 @@ void SpreadsheetView::showAllColumnsStatistics() {
 
 void SpreadsheetView::showColumnStatistics(bool forAll) {
 	QString dlgTitle(m_spreadsheet->name() + " column statistics");
-	auto* dlg = new StatisticsDialog(dlgTitle);
 	QVector<Column*> columns;
 
 	if (!forAll)
-		dlg->setColumns(selectedColumns());
+		columns = selectedColumns();
 	else if (forAll) {
 		for (int col = 0; col < m_spreadsheet->columnCount(); ++col) {
 			if (m_spreadsheet->column(col)->columnMode() == AbstractColumn::ColumnMode::Numeric)
 				columns << m_spreadsheet->column(col);
 		}
-		dlg->setColumns(columns);
-	}
-	if (dlg->exec() == QDialog::Accepted) {
-		if (forAll)
-			columns.clear();
 	}
+
+	auto* dlg = new StatisticsDialog(dlgTitle, columns);
+	dlg->setModal(true);
+	dlg->show();
+	QApplication::processEvents(QEventLoop::AllEvents, 0);
+	QTimer::singleShot(0, this, [=] () {dlg->showStatistics();});
 }
 
 void SpreadsheetView::showRowStatistics() {
 	QString dlgTitle(m_spreadsheet->name() + " row statistics");
-	auto* dlg = new StatisticsDialog(dlgTitle);
 
 	QVector<Column*> columns;
 	for (int i = 0; i < m_spreadsheet->rowCount(); ++i) {
@@ -2743,10 +2743,11 @@ void SpreadsheetView::showRowStatistics() {
 			QVector<double> rowValues;
 			for (int j = 0; j < m_spreadsheet->columnCount(); ++j)
 				rowValues << m_spreadsheet->column(j)->valueAt(i);
-			columns << new Column(QString::number(i+1), rowValues);
+			columns << new Column(i18n("Row %1").arg(i+1), rowValues);
 		}
 	}
-	dlg->setColumns(columns);
+	auto* dlg = new StatisticsDialog(dlgTitle, columns);
+	dlg->showStatistics();
 
 	if (dlg->exec() == QDialog::Accepted) {
 		qDeleteAll(columns);

src/kdefrontend/spreadsheet/StatisticsDialog.cpp

@@ -34,6 +34,7 @@
 #include <QPushButton>
 #include <QTabWidget>
 #include <QTextEdit>
+#include <QTimer>
 #include <QVBoxLayout>
 #include <QWindow>
 
@@ -43,7 +44,7 @@
 
 #include <cmath>
 
-StatisticsDialog::StatisticsDialog(const QString& title, QWidget* parent) : QDialog(parent),
+StatisticsDialog::StatisticsDialog(const QString& title, const QVector<Column*>& columns, QWidget* parent) : QDialog(parent),
 	m_twStatistics(new QTabWidget) {
 
 	QDialogButtonBox* btnBox = new QDialogButtonBox(QDialogButtonBox::Ok);
@@ -215,6 +216,25 @@ StatisticsDialog::StatisticsDialog(const QString& title, QWidget* parent) : QDia
 	                     "</tr>"
 	                     "</table>");
 
+
+	m_columns = columns;
+
+	//create tab widgets for every column and show the initial text with the placeholders
+	if (!m_columns.isEmpty()) {
+		for (auto* col : m_columns) {
+			auto* textEdit = new QTextEdit(this);
+			textEdit->setReadOnly(true);
+			m_twStatistics->addTab(textEdit, col->name());
+		}
+
+		auto* const textEdit = static_cast<QTextEdit*>(m_twStatistics->currentWidget());
+		textEdit->setHtml(m_htmlText.arg(QLatin1String("-"), QLatin1String("-"), QLatin1String("-"), QLatin1String("-"),
+									QLatin1String("-"), QLatin1String("-"), QLatin1String("-"), QLatin1String("-"), QLatin1String("-")).
+									arg(QLatin1String("-"), QLatin1String("-"), QLatin1String("-"), QLatin1String("-"), QLatin1String("-"),
+										QLatin1String("-"), QLatin1String("-"), QLatin1String("-"), QLatin1String("-")).
+									arg(QLatin1String("-"), QLatin1String("-"), QLatin1String("-")));
+	}
+
 	connect(m_twStatistics, &QTabWidget::currentChanged, this, &StatisticsDialog::currentTabChanged);
 
 	//restore saved settings if available
@@ -232,18 +252,9 @@ StatisticsDialog::~StatisticsDialog() {
 	KWindowConfig::saveWindowSize(windowHandle(), conf);
 }
 
-void StatisticsDialog::setColumns(const QVector<Column*>& columns) {
-	if (!columns.size())
-		return;
-
-	m_columns = columns;
-
-	for (auto* col : m_columns) {
-		auto* textEdit = new QTextEdit;
-		textEdit->setReadOnly(true);
-		m_twStatistics->addTab(textEdit, col->name());
-	}
-	currentTabChanged(0);
+void StatisticsDialog::showStatistics() {
+	QApplication::processEvents(QEventLoop::AllEvents, 0);
+	QTimer::singleShot(0, this, [=] () {currentTabChanged(0);});
 }
 
 const QString StatisticsDialog::isNanValue(const double value) {
@@ -275,11 +286,13 @@ QString modeValue(Column* column, double value) {
 }
 
 void StatisticsDialog::currentTabChanged(int index) {
+	auto* const textEdit = static_cast<QTextEdit*>(m_twStatistics->currentWidget());
+	if (!textEdit)
+		return;
+
 	WAIT_CURSOR;
 	const Column::ColumnStatistics& statistics = m_columns[index]->statistics();
-	RESET_CURSOR;
 
-	auto* const textEdit = static_cast<QTextEdit*>(m_twStatistics->currentWidget());
 	textEdit->setHtml(m_htmlText.arg(QString::number(statistics.size),
 									isNanValue(statistics.minimum == INFINITY ? NAN : statistics.minimum),
 									isNanValue(statistics.maximum == -INFINITY ? NAN : statistics.maximum),
@@ -301,4 +314,5 @@ void StatisticsDialog::currentTabChanged(int index) {
 						arg(isNanValue(statistics.skewness),
 							isNanValue(statistics.kurtosis),
 							isNanValue(statistics.entropy)));
+	RESET_CURSOR;
 }

src/kdefrontend/spreadsheet/StatisticsDialog.h

@@ -38,9 +38,9 @@ class StatisticsDialog : public QDialog {
 	Q_OBJECT
 
 public:
-	explicit StatisticsDialog(const QString&, QWidget *parent = nullptr);
+	explicit StatisticsDialog(const QString&, const QVector<Column*>&, QWidget *parent = nullptr);
 	~StatisticsDialog() override;
-	void setColumns(const QVector<Column*>&);
+	void showStatistics();
 
 private:
 	const QString isNanValue(const double);