Errors while compiling a test program using Qt中一样,我也遵循Jasmin Blanchette和Mark Summerfield撰写的《使用Qt 4进行C++ GUI编程》一书。我没有那个错误,无论如何我都无法建立它。在我开始编写构造函数之前,它一直可以构建。
我通过Qt加载项使用Qt 4.8和MSVC 2010。

[编辑]
我可以避免在Qt visual studio加载项中使用Qmake吗?
[/ EDIT]

我的代码:

查找对话框

#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

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("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());
}

main.cpp
#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();
}

并输出:
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。

代码之前已运行。 它可以在没有任何make-file的情况下工作。在MSVC2010中只是简单的编译:
#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();
}

最佳答案

也许这是一个初学者的问题。但是,如果我有这样的一个,也许对其他人会有帮助。

由于使用Q_OBJECT导致出现错误,因此如果没有moc,我的应用程序将无法运行。第二个示例协同工作,因为没有宏,并且不一定需要moc。

而且我可以避免编写Qmake和moc吗?我可以。 Qt Visual Studio加载项会自动生成所有必需的文件。如果有类似的问题

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)

然后重新加载定义了Q_OBJECT类的头文件(只需排除该文件,然后再次添加它)。将创建新的moc.cpp文件。然后重建项目。

我找不到有关Qt加载项的任何帮助。如果有人知道,请给我链接。

10-07 19:34
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