select all content upon receiving focus - c++

Question

I have the following problem, I have a QTableWidget to which I have added some QDoubleSpinBox to some cells, all good so far my question is how I can do to select all the content of the spinbox when changing the focus, I mean when pressing the key tab and when they receive the focus, I will appreciate any suggestions.
I leave my code:
void MainClass::setData(double val1, double val2,int _rowCount)
{
for (int i=0;i<= _rowCount; i++) {
int rowCount=ui->tableWidget_4->rowCount();
// ui->tableWidget_4->setRowCount(rowCount);
//primera columna
ui->tableWidget_4->insertRow(rowCount);
// qDebug()<<rowCount;
QTableWidgetItem *item=new QTableWidgetItem(QString("v %1").arg(v));
ui->tableWidget_4->setItem(rowCount,V,item);
//segunda columna columna
// ui->tableWidget_4->insertRow(rowCount);
QTableWidgetItem *item1=new QTableWidgetItem(0);
ui->tableWidget_4->setItem(rowCount,Velocidad,item1);
ui->tableWidget_4->setCellWidget(rowCount,Velocidad,new QDoubleSpinBox);
QDoubleSpinBox *sb=qobject_cast<QDoubleSpinBox *>(
ui->tableWidget_4->cellWidget(rowCount,Velocidad));
sb->setValue(val1);
// qDebug()<<item1->data(Qt::DisplayRole).toString();
//tercera columna columna
// ui->tableWidget_4->insertRow(rowCount);
QTableWidgetItem *item2=new QTableWidgetItem(QString("h %1").arg(h));
ui->tableWidget_4->setItem(rowCount,H,item2);
//cuarta columna columna
// ui->tableWidget_4->insertRow(rowCount);
QTableWidgetItem *item3=new QTableWidgetItem(val2);
ui->tableWidget_4->setItem(rowCount,Profundidad,item3);
ui->tableWidget_4->setCellWidget(rowCount,Profundidad,new QDoubleSpinBox);
QDoubleSpinBox *sb2=qobject_cast<QDoubleSpinBox *>(
ui->tableWidget_4->cellWidget(rowCount,Profundidad));
sb2->setValue(val2);
v++;
h++;
}
here the form
Note that when the spinboxes are in focus, only the cursor blinks but not all the content is selected.
note:
in the assignment of the column number in setItem I use an enumeration instead of the column numbers.
enum ColNames{V,Velocidad,H,Profundidad};

Answer 1

One possible solution is to override the focusInEvent method of the QDoubleSpinBox that is invoked when it receives the focus, and then select all the text.
class DoubleSpinBox: public QDoubleSpinBox{
public:
using QDoubleSpinBox::QDoubleSpinBox;
protected:
void focusInEvent(QFocusEvent *event){
QDoubleSpinBox::focusInEvent(event);
selectAll();
}
};
And then set it using the setCellWidget method.
You can also avoid using the setCellWidget method and use the delegate:
#include <QtWidgets>
#include <random>
class Helper: public QObject{
public:
Helper(QDoubleSpinBox *ds): QObject(ds), m_ds(ds){
m_ds->installEventFilter(this);
}
bool eventFilter(QObject *watched, QEvent *event){
if(watched == m_ds && event->type() == QEvent::FocusIn){
m_ds->selectAll();
}
return QObject::eventFilter(watched, event);
}
private:
QDoubleSpinBox* m_ds;
};
class Delegate: public QStyledItemDelegate{
public:
QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const{
QWidget *editor = QStyledItemDelegate::createEditor(parent, option, index);
if(QDoubleSpinBox *ds = qobject_cast<QDoubleSpinBox *>(editor)){
new Helper(ds);
}
return editor;
}
};
class MainWindow: public QMainWindow{
public:
MainWindow(QWidget *parent=nullptr):
QMainWindow(parent), table(new QTableWidget)
{
table->setColumnCount(4);
table->setItemDelegate(new Delegate);
setCentralWidget(table);
}
void append(double value1, double value2){
int number_of_rows = table->rowCount();
QTableWidgetItem *item1 = new QTableWidgetItem;
item1->setText(QString("v %1").arg(number_of_rows));
QTableWidgetItem *item2 = new QTableWidgetItem;
item2->setData(Qt::DisplayRole, value1);
QTableWidgetItem *item3 = new QTableWidgetItem;
item3->setText(QString("h %1").arg(number_of_rows));
QTableWidgetItem *item4 = new QTableWidgetItem;
item4->setData(Qt::DisplayRole, value2);
table->insertRow(number_of_rows);
table->setItem(number_of_rows, 0, item1);
table->setItem(number_of_rows, 1, item2);
table->setItem(number_of_rows, 2, item3);
table->setItem(number_of_rows, 3, item4);
table->openPersistentEditor(item2);
table->openPersistentEditor(item4);
}
private:
QTableWidget *table;
};
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
a.setStyle("fusion");
MainWindow w;
std::uniform_real_distribution<> dist(1.0, 2.0);
for(int i=0; i< 4; i++){
double val1 = dist(*QRandomGenerator::global());
double val2 = dist(*QRandomGenerator::global());
w.append(val1, val2);
}
w.resize(640, 480);
w.show();
return a.exec();
}