Qt错误:QHBoxLayout没有在此范围内声明? [英] Qt Error: QHBoxLayout was not declaredin this scope?
问题描述
我试图编译以下使用Qt 4但我得到错误。我研究了很多来源,但我没有能够解决这个问题。见下面的代码。这个程序是从Qt 4教科书。该代码根据它们工作。
I am trying to compile the following using Qt 4 but I get errors. I researched many sources but I have not been able to solve the problem. See Code below. This program is from Qt 4 textbook. The code works according to them.
.pro文件
HEADERS += \
findDialog.h
SOURCES += \
findDialog.cpp \
main.cpp
QT += widgets \
gui
FindDialog.h
FindDialog.h
#ifndef FINDDIALOG_H
#define FINDDIALOG_H
#include <QDialog>
class QCheckbox;
class QLabel;
class QLineEdit;
class QPushButton;
class FindDialog : public 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.cpp
FindDialog.cpp
#include <QtGui>
#include "findDialog.h"
#include <QCheckBox>
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(const QString &)),
this, SLOT(enableFindButton(const QString &)));
connect(findButton, SIGNAL(clicked()),
this, SLOT(findClicked()));
connect(closeButton, SIGNAL(clicked()), this, SLOT(close()));
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::CaseSensitivity : 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();
}
错误显示如下:
finddialog.cpp:25:2: error: ‘QHBoxLayout’ was not declared in this scope
QHBoxLayout *topLeftLayout = new QHBoxLayout;
^
finddialog.cpp:25:15: error: ‘topLeftLayout’ was not declared in this scope
QHBoxLayout *topLeftLayout = new QHBoxLayout;
^
finddialog.cpp:25:35: error: expected type-specifier before ‘QHBoxLayout’
QHBoxLayout *topLeftLayout = new QHBoxLayout;
^
finddialog.cpp:25:35: error: expected ‘;’ before ‘QHBoxLayout’
finddialog.cpp:29:2: error: ‘QVBoxLayout’ was not declared in this scope
QVBoxLayout *leftLayout = new QVBoxLayout;
^
finddialog.cpp:29:15: error: ‘leftLayout’ was not declared in this scope
QVBoxLayout *leftLayout = new QVBoxLayout;
^
finddialog.cpp:29:32: error: expected type-specifier before ‘QVBoxLayout’
QVBoxLayout *leftLayout = new QVBoxLayout;
^
finddialog.cpp:29:32: error: expected ‘;’ before ‘QVBoxLayout’
finddialog.cpp:34:15: error: ‘rightLayout’ was not declared in this scope
QVBoxLayout *rightLayout = new QVBoxLayout;
^
finddialog.cpp:34:33: error: expected type-specifier before ‘QVBoxLayout’
QVBoxLayout *rightLayout = new QVBoxLayout;
^
finddialog.cpp:34:33: error: expected ‘;’ before ‘QVBoxLayout’
finddialog.cpp:39:15: error: ‘mainLayout’ was not declared in this scope
QHBoxLayout *mainLayout = new QHBoxLayout;
^
finddialog.cpp:39:32: error: expected type-specifier before ‘QHBoxLayout’
QHBoxLayout *mainLayout = new QHBoxLayout;
^
finddialog.cpp:39:32: error: expected ‘;’ before ‘QHBoxLayout’
finddialog.cpp: In member function ‘void FindDialog::findClicked()’:
finddialog.cpp:50:25: error: invalid use of incomplete type ‘class QLineEdit’
QString text = lineEdit->text();
^
In file included from finddialog.cpp:3:0:
finddialog.h:8:7: error: forward declaration of ‘class QLineEdit’
class QLineEdit;
^
finddialog.cpp:51:39: error: invalid use of incomplete type ‘class QCheckbox’
Qt::CaseSensitivity cs = caseCheckBox->isChecked() ? Qt::CaseSensitivity
^
In file included from finddialog.cpp:3:0:
finddialog.h:6:7: error: forward declaration of ‘class QCheckbox’
class QCheckbox;
^
finddialog.cpp:52:17: error: expected primary-expression before ‘:’ token
: Qt::CaseInsensitive;
^
finddialog.cpp:53:21: error: invalid use of incomplete type ‘class QCheckbox’
if(backwardCheckBox->isChecked()) {
^
In file included from finddialog.cpp:3:0:
finddialog.h:6:7: error: forward declaration of ‘class QCheckbox’
class QCheckbox;
^
finddialog.cpp: In member function ‘void FindDialog::enableFindButton(const QString&)’:
finddialog.cpp:62:12: error: invalid use of incomplete type ‘class QPushButton’
findButton->setEnabled(!text.isEmpty());
^
In file included from /opt/QtSDK/Desktop/Qt/4.8.1/gcc/include/QtGui/QDialog:1:0,
from finddialog.h:4,
from finddialog.cpp:3:
/opt/QtSDK/Desktop/Qt/4.8.1/gcc/include/QtGui/qdialog.h:53:7: error: forward declaration of ‘class QPushButton’
class QPushButton;
推荐答案
包括指令以代替QLabel,QLineEdit,QPushButton,
QCheckBox的类并添加 #include
code> #include< QVBoxLayout> 。它工作很好。
I just added the #include
instruction in place of "class" for QLabel, QLineEdit, QPushButton,
QCheckBox and added #include <QHBoxLayout>
and #include <QVBoxLayout>
. It worked just fine.
我认为问题来自Qt版本。我使用Qt 5和更多,我读一本书为Qt 4。
The problem I think comes from the Qt version. I work with Qt 5 and more and I read a book for Qt 4.
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