C++ GUI Programming With Qt4 书中的一个程序 [复制链接]

FindDialog.h

#ifndef FINDDIALOG_H_
#define FINDDIALOG_H_

#include <qdialog>
#include <qlabel>
#include <qlineedit>
#include <qcheckbox>
#include <qpushbutton>

class FindDialog: public QDialog {
public:
    FindDialog(QWidget *parent = 0);
    virtual ~FindDialog();
signals:
    void findNext(const QString &str, Qt::CaseSensitivity cs);
    void findPrevious(const QString &str, Qt::CaseSensitivity cs);

private slots:
    void findChecked();
    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(const QString &)), this,
            SLOT(enableFindButton(const QString &)));
    connect(findButton, SIGNAL(clicked()), this, SLOT(findChecked()));
    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("Find");
    setFixedHeight(sizeHint().height());
}

FindDialog::~FindDialog() {
}

void FindDialog::findChecked() {
    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());
}


编译时的错误信息：

make debug
make -f Makefile.Debug
make[1]: Entering directory `D:/program/eclipse/FindDlg'
g++ -c -g -frtti -fexceptions -mthreads -Wall -DUNICODE -DQT_LARGEFILE_SUPPORT -DQT_DLL -DQT_GUI_LIB -DQT_CORE_LIB -DQT_THREAD_SUPPORT -DQT_NEEDS_QMAIN -I"c:\Qt\qt\include\QtCore" -I"c:\Qt\qt\include\QtGui" -I"c:\Qt\qt\include" -I"c:\Qt\qt\include\ActiveQt" -I"debug" -I"." -I"c:\Qt\qt\mkspecs\default" -o debug\FindDialog.o FindDialog.cpp
g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-reloc -mthreads -Wl -Wl,-subsystem,windows -o debug\FindDlg.exe debug/FindDialog.o debug/main.o  -L"c:\Qt\qt\lib" -lmingw32 -lqtmaind -lQtGuid4 -lQtCored4
debug/FindDialog.o: In function `ZN10FindDialog11findCheckedEv':
D:/program/eclipse/FindDlg/FindDialog.cpp:55: undefined reference to `FindDialog::findPrevious(QString const&, Qt::CaseSensitivity)'
D:/program/eclipse/FindDlg/FindDialog.cpp:57: undefined reference to `FindDialog::findNext(QString const&, Qt::CaseSensitivity)'
collect2: ld returned 1 exit status
make[1]: *** [debug\FindDlg.exe] Error 1
make[1]: Leaving directory `D:/program/eclipse/FindDlg'
make: *** [debug] Error 2


我是用的mingw+eclipse+cdt环境

还有就是书中虽然声明了QLabel,
QLineEdit的类，但是在编译的时候还是没用，还是要把这些头文件加上去，不然你编译不过去

我在看这个例子的时候也发现的这个问题。我想主要是因为这两个函数被声明了，但是根本就没有定义。

缺少宏Q_OBJECT

emit findPrevious(text, cs);
emit findNext(text, cs);
这两句注释掉～好像这个应用后续章节才用到，所示换个执行动作就可以通过编译了。比如加不同的QMessageBox...

同问