Errors while compiling a test program using Qt
I am pretty new to C++/Qt
I am following the book 'C++ GUI Programming with Qt 4' by Jasmin Blanchette and Mark Summerfield.
I was working on an example program and got stuck up with some compilation errors which I was not able to resolve. Code and Errors below. Any help is appreciated.
Thanks.
finddialog.h
#ifndef FINDDIALOG_H
#define FINDDIALOG_H
#include <QDialog>
class QCheckBox;
class QLabel;
class QLineEdit;
class QPushButton;
class QWidget;
class FindDialog : QDialog
{
Q_OBJECT
public:
FindDialog(QWidget *parent = 0);
signals:
void findNext(const QString &str, Qt::CaseSensitivity cs);
void findPrevious(const QString &str, Qt::CaseSensitivity cs);
private slots:
void findClicked();
void enableFindButton(const QString &text);
private:
QLabel *label;
QLineEdit *lineEdit;
QCheckBox *caseCheckBox;
QCheckBox *backwardCheckBox;
QPushButton *findButton;
QPushButton *closeButton;
};
#endif // FINDDIALOG_H
finddialog.cpp
#include <QtGui>
#include "finddialog.h"
FindDialog::FindDialog(QWidget *parent) : QDialog(parent)
{
label = new QLabel(tr("Find &what:"));
lineEdit = new QLineEdit;
label->setBuddy(lineEdit);
caseCheckBox = new QCheckBox(tr("Match &case"));
backwardCheckBox = new QCheckBox(tr("Search &backward"));
findButton = new QPushButton(tr("&Find"));
findButton->setDefault(true);
findButton->setEnabled(false);
closeButton = new QPushButton(tr("Close"));
connect(lineEdit, SIGNAL(textChanged(QString)), this, SLOT(enableFindButton(QString)));
connect(findButton, SIGNAL(clicked()), this, SLOT(findClicked()));
connect(closeButton, SIGNAL(clicked()), this, SLOT(close()));
开发者_如何学运维
QHBoxLayout *topLeftLayout = new QHBoxLayout;
topLeftLayout->addWidget(label);
topLeftLayout->addWidget(lineEdit);
QVBoxLayout *leftLayout = new QVBoxLayout;
leftLayout->addLayout(topLeftLayout);
leftLayout->addWidget(caseCheckBox);
leftLayout->addWidget(backwardCheckBox);
QVBoxLayout *rightLayout = new QVBoxLayout;
rightLayout->addWidget(findButton);
rightLayout->addWidget(closeButton);
rightLayout->addStretch();
QHBoxLayout *mainLayout = new QHBoxLayout;
mainLayout->addLayout(leftLayout);
mainLayout->addLayout(rightLayout);
setLayout(mainLayout);
setWindowTitle(tr("Find"));
setFixedHeight(sizeHint().height());
}
void FindDialog::findClicked()
{
QString text = lineEdit->text();
Qt::CaseSensitivity cs =
caseCheckBox->isChecked() ? Qt::CaseSensitive
: Qt::CaseInsensitive;
if (backwardCheckBox->isChecked()) {
emit findPrevious(text, cs);
} else {
emit findNext(text, cs);
}
}
void FindDialog::enableFindButton(const QString &text)
{
findButton->setEnabled(!text.isEmpty());
}
main.cpp
#include <QApplication>
#include "finddialog.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
FindDialog *dialog = new FindDialog;
dialog->show();
return app.exec();
}
Errors below..
c:/Qt/2010.02.1/qt/include/QtGui/../../src/gui/kernel/qwidget.h: In function 'int qMain(int, char**)': c:/Qt/2010.02.1/qt/include/QtGui/../../src/gui/kernel/qwidget.h:485: error: 'void QWidget::show()' is inaccessible main.cpp:7: error: within this context main.cpp:7: error: 'QWidget' is not an accessible base of 'FindDialog'
You should inherit publically from QWidget
or QDialog
:
class FindDialog : public QDialog {
// ...
show()
is actually implemented by a base of FindDialog
, QWidget
- but you are not inheriting publically from it and thus can't access it.
Inheritance for classes is by default private, i.e.
class A : B {};
and
class A : private B {};
are equivalent.
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