How to update QLineEdit in a QDialog

frnklu20

In the program that i'm developing, there is a QDialog class named BarramDialog that contains 4 QLineEdit Widgets and there is a class named Diagrama.

barramdialog.h

class BarramDialog;
}

class BarramDialog : public QDialog
{
    Q_OBJECT

public:
    explicit BarramDialog(QWidget *parent = nullptr);
    ~BarramDialog();
    QString nome="pegadinha";
    int num=42;
    float tensao;
    float ang;

    QString nome_dialog(QString &);
    void setdata(QList<QString>&);
    QList<QString> data=QList<QString>() <<""<<""<<""<<"";

As you can see, in my class BarramDialog there is a QList<QString> variable that is responsible to set the text of the QLineEdit widgets when i execute the dialog:

barramdialog.cpp

BarramDialog::BarramDialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::BarramDialog)
{
    ui->setupUi(this);

    ui->ang_lin->setText(data[0]);
    ui->tensao_line->setText(data[1]);
    ui->num_lin->setText(data[2]);
    ui->nome_lin->setText(data[3]);
    update();
}

The problem is:

diagrama.cpp

void Diagrama::showMousePosition(const QPoint &pos, const QVariant property)
{
    if(modo=="info")
    {

         BarramDialog *info=new BarramDialog;
         QList<QString> listagem= QList<QString>() <<QString::number(BarramentoMap[property.toString()]->ang)
                 <<QString::number(BarramentoMap[property.toString()]->tensao)
                 <<QString::number(BarramentoMap[property.toString()]->num)
                 <<BarramentoMap[property.toString()]->nome;
         info->setModal(true);
         info->setdata(listagem);


         info->exec();
    }

the function setdata of BarramDialog is

void BarramDialog::setdata(QList<QString> &new_list)
{
   data=new_list;
}

But when i use this function and execute the dialog, the text on QLineEdit widget stay the same.

How can i fix it?

Pablo J. Rogina

@frnklu20 what about something like this (pseudo-code):

BarramDialog::BarramDialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::BarramDialog)
{
    ui->setupUi(this);
    updateLineEdits();
    ....
}

void BarramDialog::updateLineEdits()
{
     ui->ang_lin->setText(data[0]);
     ui->tensao_line->setText(data[1]);
     ui->num_lin->setText(data[2]);
     ui->nome_lin->setText(data[3]);
}

void BarramDialog::setdata(QList<QString> &new_list)
{
   data=new_list;
   updateLineEdits();
}

Gojir4

@frnklu20 Hi,

Your QLineEdit are not updated because you don't update them in your method setData.

I suggest to change setData like this:

void BarramDialog::setdata(const QList<QString> &new_list)
{
   ui->ang_lin->setText(data[0]);
   ui->tensao_line->setText(data[1]);
   ui->num_lin->setText(data[2]);
   ui->nome_lin->setText(data[3]);
}

Other points:

There is a memory leak issue in showMousePosition(). You have to set a parent to your dialog, or to destroy it at the end of the function:

BarramDialog *info=new BarramDialog(this);

//OR
BarramDialog *info=new BarramDialog;
...
info.deleteLater(); //put at the end of showMousePosition()

Even simple, declare it on the stack:

BarramDialog info;
...
info.exec()

I have modified the parameter type in setData to const QList<QString> &new_list. I have added the const directive as there is no reason to pass it by non-const reference.

jsulm

@Gojir4 @frnklu20 Actually there is no need for heap allocation of BarramDialog.

void Diagrama::showMousePosition(const QPoint &pos, const QVariant property)
{
    if(modo=="info")
    {
        BarramDialog info;
        ...
        info.exec();
    }
    ...
}

frnklu20

Thank you!!