LineEdit with clearbutton ...

can anybody tell me why the example below stops working when I use a QWidget derived object instead of a QWidget object in line 37/38? Using an objekt derived from QToolButton works fine though ...

Code:

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#include <QApplication>
#include <QtGui>
 
#ifndef LINEEDIT_H
#define LINEEDIT_H
 
class LineEdit : public QLineEdit
{
    Q_OBJECT
    public:
        LineEdit(QWidget *parent=0);
    private:
        QWidget *clearWidget;
    private slots:
        void updateClearWidget(const QString& text);
    protected:
        void resizeEvent(QResizeEvent *);
};
#endif
 
#ifndef CLEARWIDGET_H
#define CLEARWIDGET_H
 
class ClearWidget : public QWidget
{
    Q_OBJECT
    public:
        ClearWidget(QWidget *parent=0) : QWidget(parent) {}
};
#endif
 
/* Implementation of LineEdit */
 
LineEdit::LineEdit(QWidget *parent)
    : QLineEdit(parent)
{
    //clearWidget = new ClearWidget(this); // comment out this line and uncomment then next line and things won't work anymore
     clearWidget = new QWidget(this);
    clearWidget->setStyleSheet("QWidget { background-color:gray; }");
 
    clearWidget->hide();
    connect(this, SIGNAL(textChanged(const QString&)), SLOT(updateClearWidget(const QString&)));
 
    QSize sz = sizeHint();
    int frameWidth = style()->pixelMetric(QStyle::PM_DefaultFrameWidth);
    this->setStyleSheet(QString("QLineEdit { padding-right:%1px; }").arg(sz.height() + frameWidth));
}
 
void LineEdit::updateClearWidget(const QString& text)
{
    clearWidget->setVisible(!text.isEmpty());
}
 
void LineEdit::resizeEvent(QResizeEvent *)
{
    QSize sz = sizeHint();
    int frameWidth = style()->pixelMetric(QStyle::PM_DefaultFrameWidth);
    clearWidget->resize(sz.height(), sz.height());
    clearWidget->move(rect().right() - clearWidget->width() - frameWidth,
             (rect().bottom() + 1 - clearWidget->height())/2);
}
 
/* Main */
 
#include "main.moc"
int main(int argc, char **argv)
{
    QApplication app(argc, argv);
    LineEdit * le = new LineEdit;
    le->show();
    return app.exec();
}

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thanx in advance

Probably because its contents causes the stylesheet to be ignored (if that is what you mean).

Quote:

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Originally Posted by wysota

Probably because its contents causes the stylesheet to be ignored (if that is what you mean).

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Well, it has no content and worse than that, the widget itself is not shown at all. Actually the ClearWidget does not differ from an ordinary QWidget so why isn't it displayed? I even tried to fill it with some content but even then you see a pixel or two but not a proper widget. Trying to resize the widget or to set a fixed size didn't help either :(.

http://trolltech.com/developer/task-...ntry&id=166742

Quote:

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Resolution: QWidget, QDialog are special widgets in the sense that they do not have a paintEvent. In Qt, we paint through the backing store. For custom widgets that directly inherit from QWidget and QDialog, one needs to provide a paintEvent as below:

Code:

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void paintEvent(QPaintEvent *)
{
        QStyleOption opt;
        opt.init(this);
        QPainter p(this);
        style()->drawPrimitive(QStyle::PE_Widget, &opt, &p, this);
}

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