正如在使用 Qt 编译测试程序时出现的错误中一样，我也在关注 Jasmin Blanchette 和 Mark Summerfield 所著的“C++ GUI Programming with Qt 4”一书。我没有那个错误，无论如何我无法构建它。在我开始编写构造函数之前，它一直能够构建。我通过 Qt 插件使用 Qt 4.8 和 MSVC 2010。
[编辑] 我可以避免在 Qt Visual Studio 插件中使用 Qmake 吗？ [/编辑]
我的代码：
查找对话框.h
#ifndef FindDialog_H
#define FindDialog_H
#include <qdialog.h>
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 findPrev(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
查找对话框.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("Serch 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(findClicked()), this, SLOT(clicked()));
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);
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 findPrev(text, cs);
else emit findNext(text, cs);
}
void FindDialog::enableFindButton(const QString &text)
{
findButton->setEnabled(!text.isEmpty());
}
主文件
#include <qapplication.h>
#include <finddialog.h>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
FindDialog *dialog = new FindDialog;
dialog->show();
return app.exec();
}
和输出：
1>------ Build started: Project: ex1, Configuration: Release Win32 ------
1>Build started 26.03.2013 23:36:17.
1>InitializeBuildStatus:
1> Touching "Release\ex1.unsuccessfulbuild".
1>ClCompile:
1> finddialog.cpp
1> main.cpp
1> Generating Code...
1>finddialog.obj : error LNK2019: unresolved external symbol "public: static struct QMetaObject const FindDialog::staticMetaObject" (?staticMetaObject@FindDialog@@2UQMetaObject@@B) referenced in function "public: static class QString __cdecl FindDialog::tr(char const *,char const *)" (?tr@FindDialog@@SA?AVQString@@PBD0@Z)
1>finddialog.obj : error LNK2019: unresolved external symbol "protected: void __thiscall FindDialog::findNext(class QString const &,enum Qt::CaseSensitivity)" (?findNext@FindDialog@@IAEXABVQString@@W4CaseSensitivity@Qt@@@Z) referenced in function "private: void __thiscall FindDialog::findClicked(void)" (?findClicked@FindDialog@@AAEXXZ)
1>finddialog.obj : error LNK2019: unresolved external symbol "protected: void __thiscall FindDialog::findPrev(class QString const &,enum Qt::CaseSensitivity)" (?findPrev@FindDialog@@IAEXABVQString@@W4CaseSensitivity@Qt@@@Z) referenced in function "private: void __thiscall FindDialog::findClicked(void)" (?findClicked@FindDialog@@AAEXXZ)
1>finddialog.obj : error LNK2001: unresolved external symbol "public: virtual struct QMetaObject const * __thiscall FindDialog::metaObject(void)const " (?metaObject@FindDialog@@UBEPBUQMetaObject@@XZ)
1>finddialog.obj : error LNK2001: unresolved external symbol "public: virtual void * __thiscall FindDialog::qt_metacast(char const *)" (?qt_metacast@FindDialog@@UAEPAXPBD@Z)
1>finddialog.obj : error LNK2001: unresolved external symbol "public: virtual int __thiscall FindDialog::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@FindDialog@@UAEHW4Call@QMetaObject@@HPAPAX@Z)
1>C:\Users\Family\Documents\Visual Studio 2010\Projects\ex1\Win32\Release\\ex1.exe : fatal error LNK1120: 6 unresolved externals
1>
1>Build FAILED.
1>
1>Time Elapsed 00:00:02.21
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
谢谢你。
代码之前已经运行过。它在没有任何 make-file 的情况下工作。只需在 MSVC2010 中进行简单编译：
#include <QApplication>
#include <QHBoxLayout>
#include <QSlider>
#include <QSpinBox>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QWidget *window = new QWidget;
window->setWindowTitle("Enter Your Age");
QSpinBox *spinBox = new QSpinBox;
QSlider *slider = new QSlider(Qt::Horizontal);
spinBox->setRange(0, 130);
slider->setRange(0, 130);
QObject::connect(spinBox, SIGNAL(valueChanged(int)),
slider, SLOT(setValue(int)));
QObject::connect(slider, SIGNAL(valueChanged(int)),
spinBox, SLOT(setValue(int)));
spinBox->setValue(35);
QHBoxLayout *layout = new QHBoxLayout;
layout->addWidget(spinBox);
layout->addWidget(slider);
window->setLayout(layout);
window->show();
return app.exec();
}