我正在尝试从qt书中编译对话程序.我一直收到这个错误:
:'QLabel':类没有构造函数
亲们:
QT += core gui greaterThan(QT_MAJOR_VERSION, 4): QT += widgets TARGET = untitled TEMPLATE = app SOURCES += main.cpp\ mainwindow.cpp \ finddialog.cpp HEADERS += mainwindow.h \ finddialog.h FORMS += mainwindow.ui
主要:
#include#include "finddialog.h" int main(int argc, char *argv[]) { QApplication app(argc, argv); FindDialog *dialog = new FindDialog; dialog->show(); return app.exec(); }
标题:
#ifndef FINDDIALOG_H #define FINDDIALOG_H #includeclass QCheckBox; class QLabel; class QLineEdit; class QPushButton; class QWidget; 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_H
实行:
#include#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(QString)), this, SLOT(enableFindButton(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::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()); }
lpapp.. 5
:'QLabel':类没有构造函数
看来你包括QtGui而不是QtWidgets.替换此行:
#include
同
#include
如果您正在使用Qt 5构建.本书是为Qt 4编写的,并且小部件类移动到他们自己的模块中.
免责声明:包含整个模块是一个坏主意.