QPushButton gets stuck drawing pressed when transfer of focus to button interrupted

Hello

I have some forms with input fields that provide warnings to the user when the fields looses focus (if something is wrong of course). To that end Iâ€™ve created my own control that inherits from QLineEdit. For this question consider the extremely simple field that will pop a message box whenever focus is lost when there is text in the control. The actual controls have more logic but all are supposed to pop a message box.

Code:

class test_line_edit : public QLineEdit
{
  Q_OBJECT
 
public:
  test_line_edit(QWidget * parent = 0) : QLineEdit(parent)
  {}
 
  ~test_line_edit(){}
 
protected:  
  virtual void focusOutEvent(QFocusEvent * e)
  {
    if(!text().isEmpty())
    {
      QMessageBox msg;
      msg.setText(tr("Test"));
      msg.exec();
      setFocus(Qt::OtherFocusReason);
    }
    else
    {
      QLineEdit::focusOutEvent(e);
    }
  }
 
};

Now say I have a simple form with just one of these controls and a QPushButton. If the user types in the control and then clicks the button the messagebox pops but the button gets stuck being drawn looking like itâ€™s pressed. How can I make that stop? As best I can tell the QPushButtonâ€™s pressed signal is getting fired but that is all I can hear from the button. Since these test_line_edit controls are going to be used everywhere on many different forms Iâ€™m hoping there is something I can change inside the test_line_edit class that will fix the problem. Running Qt 4.7.0 on Windows using Visual Studio 2010.

Iâ€™ve seen this bug and not sure if itâ€™s related since itâ€™s a different platform and Iâ€™m not actually holding the button down: http://bugreports.qt.nokia.com/browse/QTBUG-7901

Hereâ€™s a full program that demonstrates the problem (warning: some code generated from the VS plugin)

main.h:

Code:

#include <QtGui/QMainWindow>
 
#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QHeaderView>
#include <QtGui/QMainWindow>
#include <QtGui/QMenuBar>
#include <QtGui/QPushButton>
#include <QtGui/QStatusBar>
#include <QtGui/QToolBar>
#include <QtGui/QVBoxLayout>
#include <QtGui/QWidget>
 
#include <QLineEdit>
#include <QMessageBox>
 
class test_line_edit : public QLineEdit
{
  Q_OBJECT
 
public:
  test_line_edit(QWidget * parent = 0) : QLineEdit(parent)
  {}
 
  ~test_line_edit(){}
 
protected:  
  virtual void focusOutEvent(QFocusEvent * e)
  {
    if(!text().isEmpty())
    {
      QMessageBox msg;
      msg.setText(tr("Test"));
      msg.exec();
      //setFocus(Qt::OtherFocusReason);
    }
    else
    {
      QLineEdit::focusOutEvent(e);
    }
 
    QLineEdit::focusOutEvent(e);
  }
 
};
 
QT_BEGIN_NAMESPACE
 
class Ui_btn_drawing_testClass
{
public:
    QWidget *centralWidget;
    QVBoxLayout *verticalLayout;
    test_line_edit *line_edit;
    QPushButton *btn;
    QMenuBar *menuBar;
    QToolBar *mainToolBar;
    QStatusBar *statusBar;
 
    void setupUi(QMainWindow *btn_drawing_testClass)
    {
        if (btn_drawing_testClass->objectName().isEmpty())
            btn_drawing_testClass->setObjectName(QString::fromUtf8("btn_drawing_testClass"));
        btn_drawing_testClass->resize(167, 127);
        centralWidget = new QWidget(btn_drawing_testClass);
        centralWidget->setObjectName(QString::fromUtf8("centralWidget"));
        verticalLayout = new QVBoxLayout(centralWidget);
        verticalLayout->setSpacing(6);
        verticalLayout->setContentsMargins(11, 11, 11, 11);
        verticalLayout->setObjectName(QString::fromUtf8("verticalLayout"));
        line_edit = new test_line_edit(centralWidget);
        line_edit->setObjectName(QString::fromUtf8("line_edit"));
 
        verticalLayout->addWidget(line_edit);
 
        btn = new QPushButton(centralWidget);
        btn->setObjectName(QString::fromUtf8("btn"));
 
        verticalLayout->addWidget(btn);
 
        btn_drawing_testClass->setCentralWidget(centralWidget);
        menuBar = new QMenuBar(btn_drawing_testClass);
        menuBar->setObjectName(QString::fromUtf8("menuBar"));
        menuBar->setGeometry(QRect(0, 0, 167, 20));
        btn_drawing_testClass->setMenuBar(menuBar);
        mainToolBar = new QToolBar(btn_drawing_testClass);
        mainToolBar->setObjectName(QString::fromUtf8("mainToolBar"));
        btn_drawing_testClass->addToolBar(Qt::TopToolBarArea, mainToolBar);
        statusBar = new QStatusBar(btn_drawing_testClass);
        statusBar->setObjectName(QString::fromUtf8("statusBar"));
        btn_drawing_testClass->setStatusBar(statusBar);
 
        retranslateUi(btn_drawing_testClass);
 
        QMetaObject::connectSlotsByName(btn_drawing_testClass);
    } // setupUi
 
    void retranslateUi(QMainWindow *btn_drawing_testClass)
    {
        btn_drawing_testClass->setWindowTitle(QApplication::translate("btn_drawing_testClass", "btn_drawing_test", 0, QApplication::UnicodeUTF8));
        btn->setText(QApplication::translate("btn_drawing_testClass", "PushButton", 0, QApplication::UnicodeUTF8));
    } // retranslateUi
 
};
 
namespace Ui {
    class btn_drawing_testClass: public Ui_btn_drawing_testClass {};
} // namespace Ui
 
QT_END_NAMESPACE
 
class btn_drawing_test : public QMainWindow
{
    Q_OBJECT
 
public:
  btn_drawing_test(QWidget *parent = 0, Qt::WFlags flags = 0): QMainWindow(parent, flags)
  {
    ui.setupUi(this);
  }
  ~btn_drawing_test(){}
 
private:
    Ui::btn_drawing_testClass ui;
 
protected slots:
  void on_btn_clicked()
  {
    int breakpoint = 5;
  }
  void on_btn_pressed()
  {
    int breakpoint = 5;
  }    
  void on_btn_toggled(bool)
  {
    int breakpoint = 5;
  }
};

main.cpp:

Code:

#include <QtGui/QApplication>
#include "main.h"
 
 
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    btn_drawing_test w;
    w.show();
    return a.exec();
}

Thank you for your help and please let me know if I can provide any more information.