CODEWITHSUNDEEP
qtqt-designerqlineedit
GG.
GG.

Reputation: 2951

Select text of QLineEdit on focus

I have created a dialog using QtDesigner. There is a QLineEdit object in the dialog with some default content. When the dialog initializes and the focus goes to the QLineEdit, I want the default content to be auto selected, so once the user start writing, the previous content will be overwritten.

EDIT:

In constructor:

dialog->accept();

and

connect( dialog, SIGNAL(accepted()), QlineObj, SLOT( selectAll() ) );

Upvotes: 18

Views: 18693

Answers (4)

Tobias Leupold
Tobias Leupold

Reputation: 1722

Create a class derived from QLineEdit and override the focusInEvent in the header:

void focusInEvent(QFocusEvent *event) override;

Then implement it like so:

void MyLineEdit::focusInEvent(QFocusEvent *event)
{
    // First let the base class process the event
    QLineEdit::focusInEvent(event);
    // Then select the text by a single shot timer, so that everything will
    // be processed before (calling selectAll() directly won't work)
    QTimer::singleShot(0, this, &QLineEdit::selectAll);
}

Upvotes: 14

Catcow
Catcow

Reputation: 27

You can use QApplication::focusChanged along with QTimer::singleShot to select all the text on a changed focus.

Normally your QApplication is declared in main, so use QObject::connect there, eg:

int main(int argc, char *argv[]) {
    QApplication a(argc, argv);
    My_Main_Window w();
    QObject::connect(&a, SIGNAL(focusChanged(QWidget*, QWidget*)),
                     &w, SLOT(my_focus_changed_slot(QWidget*, QWidget*)));
    w.show();

    return a.exec();
}

Remember to make the public slot in the My_Main_Window class:

public slots:
void my_focus_changed_slot(QWidget*, QWidget*);

Then in your definition of my_focus_changed_slot, check if the second QWidget* (which points to the newly focused widget) is the same as the QLineEdit you wish to select all of, and do so using QTimer::singleShot so that the event loop gets called, then the QLineEdit has the selectAll slot called immediately after, eg

void My_Main_Window::focus_changed(QWidget*, QWidget* new_widget) {
    if (new_widget == my_lineedit) {
        QTimer::singleShot(0, my_lineedit, &QLineEdit::selectAll);
    }
}

where my_lineedit is a pointer to a QLineEdit and is part of the My_Main_Window class.

Upvotes: 0

Rob
Rob

Reputation: 3513

There is a simpler method to get almost the same behaviour, which is to set the default content using setPlaceholderText() instead of setText(). This will show the default content grayed out and as soon as the QLineEdit gains focus, it will disappear.

Upvotes: 8

andref
andref

Reputation: 4492

Call

lineEdit->selectAll();

after you set the default text. (In the dialog constructor, perhaps.)

Upvotes: 12

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