我正在尝试使用QtCreater编译以下程序，但是我在这个程序中遇到了很多错误。我从一本书中得到了这个程序，我无法弄清楚错误的位置。有人可以帮助调试这个程序。
这是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
#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(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());
}
的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();
}
我得到的错误如下：
finddialog.cpp:21:32: note: candidates are:
In file included from /usr/include/qt5/QtCore/qabstractanimation.h:45:0,
from /usr/include/qt5/QtCore/QtCore:4,
from /usr/include/qt5/QtGui/QtGui:4,
from finddialog.cpp:1:
/usr/include/qt5/QtCore/qobject.h:199:36: note: static QMetaObject::Connection QObject::connect(const QObject*, const char*, const QObject*, const char*, Qt::ConnectionType)
static QMetaObject::Connection connect(const QObject *sender, const char *signal,
^
/usr/include/qt5/QtCore/qobject.h:199:36: note: no known conversion for argument 1 from ‘QPushButton*’ to ‘const QObject*’
/usr/include/qt5/QtCore/qobject.h:202:36: note: static QMetaObject::Connection QObject::connect(const QObject*, const QMetaMethod&, const QObject*, const QMetaMethod&, Qt::ConnectionType)
static QMetaObject::Connection connect(const QObject *sender, const QMetaMethod &signal,
^
/usr/include/qt5/QtCore/qobject.h:202:36: note: no known conversion for argument 1 from ‘QPushButton*’ to ‘const QObject*’
/usr/include/qt5/QtCore/qobject.h:418:32: note: QMetaObject::Connection QObject::connect(const QObject*, const char*, const char*, Qt::ConnectionType) const
inline QMetaObject::Connection QObject::connect(const QObject *asender, const char *asignal,
^
/usr/include/qt5/QtCore/qobject.h:418:32: note: no known conversion for argument 1 from ‘QPushButton*’ to ‘const QObject*’
/usr/include/qt5/QtCore/qobject.h:215:43: note: template<class Func1, class Func2> static QMetaObject::Connection QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, const typename QtPrivate::FunctionPointer<Func2>::Object*, Func2, Qt::ConnectionType)
static inline QMetaObject::Connection connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal,
^
/usr/include/qt5/QtCore/qobject.h:215:43: note: template argument deduction/substitution failed:
/usr/include/qt5/QtCore/qobject.h: In substitution of ‘template<class Func1, class Func2> static QMetaObject::Connection QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, const typename QtPrivate::FunctionPointer<Func2>::Object*, Func2, Qt::ConnectionType) [with Func1 = const char*; Func2 = const char*]’:
finddialog.cpp:21:32: required from here
/usr/include/qt5/QtCore/qobject.h:215:43: error: no type named ‘Object’ in ‘struct QtPrivate::FunctionPointer<const char*>’
/usr/include/qt5/QtCore/qobject.h:245:13: note: template<class Func1, class Func2> static typename QtPrivate::QEnableIf<((int)(QtPrivate::FunctionPointer<Func2>::ArgumentCount) >= 0), QMetaObject::Connection>::Type QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, Func2)
connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 slot)
^
/usr/include/qt5/QtCore/qobject.h:245:13: note: template argument deduction/substitution failed:
finddialog.cpp:21:32: note: candidate expects 3 arguments, 4 provided
this, SLOT(findClicked()));
^
In file included from /usr/include/qt5/QtCore/qabstractanimation.h:45:0,
from /usr/include/qt5/QtCore/QtCore:4,
from /usr/include/qt5/QtGui/QtGui:4,
from finddialog.cpp:1:
/usr/include/qt5/QtCore/qobject.h:268:13: note: template<class Func1, class Func2> static typename QtPrivate::QEnableIf<(QtPrivate::FunctionPointer<Func2>::ArgumentCount == (-1)), QMetaObject::Connection>::Type QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, Func2)
connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 slot)
^
/usr/include/qt5/QtCore/qobject.h:268:13: note: template argument deduction/substitution failed:
finddialog.cpp:21:32: note: candidate expects 3 arguments, 4 provided
this, SLOT(findClicked()));
^
finddialog.cpp:23:61: error: no matching function for call to ‘FindDialog::connect(QPushButton*&, const char [11], FindDialog* const, const char [9])’
connect(closeButton, SIGNAL(clicked()), this, SLOT(close()));
^
finddialog.cpp:23:61: note: candidates are:
In file included from /usr/include/qt5/QtCore/qabstractanimation.h:45:0,
from /usr/include/qt5/QtCore/QtCore:4,
from /usr/include/qt5/QtGui/QtGui:4,
from finddialog.cpp:1:
/usr/include/qt5/QtCore/qobject.h:199:36: note: static QMetaObject::Connection QObject::connect(const QObject*, const char*, const QObject*, const char*, Qt::ConnectionType)
static QMetaObject::Connection connect(const QObject *sender, const char *signal,
^
/usr/include/qt5/QtCore/qobject.h:199:36: note: no known conversion for argument 1 from ‘QPushButton*’ to ‘const QObject*’
/usr/include/qt5/QtCore/qobject.h:202:36: note: static QMetaObject::Connection QObject::connect(const QObject*, const QMetaMethod&, const QObject*, const QMetaMethod&, Qt::ConnectionType)
static QMetaObject::Connection connect(const QObject *sender, const QMetaMethod &signal,
^
/usr/include/qt5/QtCore/qobject.h:202:36: note: no known conversion for argument 1 from ‘QPushButton*’ to ‘const QObject*’
/usr/include/qt5/QtCore/qobject.h:418:32: note: QMetaObject::Connection QObject::connect(const QObject*, const char*, const char*, Qt::ConnectionType) const
inline QMetaObject::Connection QObject::connect(const QObject *asender, const char *asignal,
^
/usr/include/qt5/QtCore/qobject.h:418:32: note: no known conversion for argument 1 from ‘QPushButton*’ to ‘const QObject*’
/usr/include/qt5/QtCore/qobject.h:215:43: note: template<class Func1, class Func2> static QMetaObject::Connection QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, const typename QtPrivate::FunctionPointer<Func2>::Object*, Func2, Qt::ConnectionType)
static inline QMetaObject::Connection connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal,
^
/usr/include/qt5/QtCore/qobject.h:215:43: note: template argument deduction/substitution failed:
/usr/include/qt5/QtCore/qobject.h: In substitution of ‘template<class Func1, class Func2> static QMetaObject::Connection QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, const typename QtPrivate::FunctionPointer<Func2>::Object*, Func2, Qt::ConnectionType) [with Func1 = const char*; Func2 = const char*]’:
finddialog.cpp:23:61: required from here
/usr/include/qt5/QtCore/qobject.h:215:43: error: no type named ‘Object’ in ‘struct QtPrivate::FunctionPointer<const char*>’
/usr/include/qt5/QtCore/qobject.h:245:13: note: template<class Func1, class Func2> static typename QtPrivate::QEnableIf<((int)(QtPrivate::FunctionPointer<Func2>::ArgumentCount) >= 0), QMetaObject::Connection>::Type QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, Func2)
connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 slot)
^
/usr/include/qt5/QtCore/qobject.h:245:13: note: template argument deduction/substitution failed:
finddialog.cpp:23:61: note: candidate expects 3 arguments, 4 provided
connect(closeButton, SIGNAL(clicked()), this, SLOT(close()));
^
In file included from /usr/include/qt5/QtCore/qabstractanimation.h:45:0,
from /usr/include/qt5/QtCore/QtCore:4,
from /usr/include/qt5/QtGui/QtGui:4,
from finddialog.cpp:1:
/usr/include/qt5/QtCore/qobject.h:268:13: note: template<class Func1, class Func2> static typename QtPrivate::QEnableIf<(QtPrivate::FunctionPointer<Func2>::ArgumentCount == (-1)), QMetaObject::Connection>::Type QObject::connect(const typename QtPrivate::FunctionPointer<Func>::Object*, Func1, Func2)
connect(const typename QtPrivate::FunctionPointer<Func1>::Object *sender, Func1 signal, Func2 slot)
^
/usr/include/qt5/QtCore/qobject.h:268:13: note: template argument deduction/substitution failed:
finddialog.cpp:23:61: note: candidate expects 3 arguments, 4 provided
connect(closeButton, SIGNAL(clicked()), this, SLOT(close()));
^
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 /usr/include/qt5/QtWidgets/QDialog:1:0,
from finddialog.h:4,
from finddialog.cpp:3:
/usr/include/qt5/QtWidgets/qdialog.h:52:7: error: forward declaration of ‘class QPushButton’
class QPushButton;
^
make: *** [finddialog.o] Error 1
答案 0 :(得分：13)
错误应该来自您的.pro文件，因为您使用的是Qt5，您应该包括：
QT += widgets
更改
的所有实例#include <QtGui>
到
#include <QtWidgets>
但是包含你需要的文件而不是整个QtGui或QtWidgets要好得多。
答案 1 :(得分：6)
findDialog.h头文件中的'class'前向声明不起作用，因此无法找到QLabel等的构造函数。用相应的#include替换每个类，如下所示。 （在finddialog.h文件中不需要QHBoxLayout和QVBoxLayout，但为方便起见，我也移动了所有必需的包含在同一个地方）。
#include <QDialog>
#include <QCheckBox> //class QCheckBox;
#include <QLabel> //class QLabel;
#include <QLineEdit> //class QLineEdit;
#include <QPushButton> //class QPushButton;
#include <QHBoxLayout> //in the finddialog.cpp
#include <QVBoxLayout> //in the finddialog.cpp
将.pro文件编辑为：
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = find
TEMPLATE = app
HEADERS = finddialog.h
SOURCES = finddialog.cpp \
main.cpp
删除所有旧的makefile和find.pro.user并重建项目。
答案 2 :(得分：3)
从Qt4移动时，您需要更改许多项目。以下是根据我的经验（来自http://www.gpupowered.org/node/23）的列表。无论如何，这不是一个完整的清单。
QtGui中QWidget定义的错误。如已建议的那样在.pro文件中添加Qt + =小部件。
有些像#include“QGraphicsItem”，需要QtWidgets / QGraphicsItem，QtWidgets / QVBoxLayout
QGtring :: toAscii（）== xgxperfserver.cpp中的QString :: toLatin1（）
Qt + =需要小部件，以避免链接所有小部件的错误
Project ERROR：QT中的未知模块：svg == svg在Qt中不是默认值，需要qtsvg
QApplication == QtWidgets / QApplication
需要明确声明“QtWidgets / QGraphicsProxyWidget”
包含要明确声明的“QtWidgets / QGraphicsDropShadowEffect”
包含要明确声明的“QDebug”
如果项目包含.ui文件，并且需要ui_mainwindow.h，还需要添加QT + = widgets，以便调用uic来生成ui文件
添加QtWidgets，＃include“QtWidgets / QGraphicsEffect”
添加QtWidgets，＃include“QtWidgets / QGraphicsView”
包括“QtWidgets / QPushButton”
QGraphicsItem :: Scale变为QGraphicsItem :: setScale
QApplication :: sendEvent成为QCoreApplication :: sendEvent
QGraphicsDropShadowEffect变为QtWidgets / QGraphicsDropShadowEffect
答案 3 :(得分：1)
我也在读同一本书。问题来自Qt的版本。这本书是为Qt4编写的，当你尝试使用Qt5时。解决问题的最简单方法是更改以下行。
在 FindDialog.pro 中添加：
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
并在 FindDialog.cpp 中更改#include <QtGui>行：
#include <QtWidgets>
您不需要包含更多内容，现在应该编译时没有错误。有关它的更多信息，请查看有关transition from Qt4 to Qt5。
的Qt文档答案 4 :(得分：0)
对我来说，qmake -v举报QMake version 3.0和Qt version 5.3.0，其工作原理如下：
1）将这两行添加到find.pro：
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
2）在find.h中保留前向声明，并在find.cpp中使用下面的包含：
#include <QCheckBox>
#include <QLineEdit>
#include <QLabel>
#include <QPushButtons>
#include <QHBoxLayout>
#include <QVBoxLayout>