从 Qt 中的信号调用成员函数的问题
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【中文标题】从 Qt 中的信号调用成员函数的问题【英文标题】:Problem Calling member function from a signal in Qt 【发布时间】:2020-02-09 21:29:06 【问题描述】:所以,我正在使用 Qt4 作为 GUI 框架在 C++ 中制作一个简单的计算器应用程序。 我以前使用过 Qt,但这次我使用的是 C++ 而不是 python。
现在我的项目中有三个文件,
main.cpp (调用和运行主 GUI 类的简单套件) window.cpp (包含实现 GUI 类和其他例程的文件套件。) header.h (window.cpp
文件的模板。)
主要的 GUI 实现类称为 Ui_MainWindow
。
现在,这个类有一个名为handleButton
的成员函数
我想做的是在
clicked
事件发生时调用这个handlebutton
函数。 所以,我应该做的是将事件连接到插槽 (handlebutton
) ,对吗??
按钮的名称是pushButton
,如上所述,handlebutton
是一个成员函数
班级Ui_MainWindow
这里是后面应该实现的 sn-p:
QObject::connect( pushButton , SIGNAL (clicked()), this , handleButton );
那么,当这个点击事件发生时this->handleButton
应该被调用,对吧??
但我收到一个错误:
error: no matching function for call to ‘QObject::connect(QPushButton*&, const char [11], Ui_MainWindow*, void (&)())
QObject::connect( pushButton , SIGNAL (clicked()), this , handleButton );
我尝试将成员 func 设为静态并尝试了所有我能想到的方法,但它似乎对我不起作用。
请指导我如何解决此问题。
文件:window.cpp
#include <iostream>
#include <window.h>
void Ui_MainWindow::handleButton ( void )
std::cout << "Hi this is MEeeeee!.\n";
return;
void Ui_MainWindow::setupUi(QMainWindow *MainWindow)
if (MainWindow->objectName().isEmpty())
MainWindow->setObjectName(QString::fromUtf8("MainWindow"));
MainWindow->resize(423, 410);
MainWindow->setMaximumSize(QSize(700, 600));
centralwidget = new QWidget(MainWindow);
centralwidget->setObjectName(QString::fromUtf8("centralwidget"));
gridLayout_2 = new QGridLayout(centralwidget);
gridLayout_2->setObjectName(QString::fromUtf8("gridLayout_2"));
label_2 = new QLabel(centralwidget);
label_2->setObjectName(QString::fromUtf8("label_2"));
label_2->setMaximumSize(QSize(16777215, 41));
QFont font;
font.setPointSize(20);
label_2->setFont(font);
label_2->setAlignment(Qt::AlignCenter);
gridLayout_2->addWidget(label_2, 0, 0, 1, 1);
label = new QLabel(centralwidget);
label->setObjectName(QString::fromUtf8("label"));
QFont font1;
font1.setFamily(QString::fromUtf8("Roboto"));
font1.setPointSize(22);
label->setFont(font1);
label->setLayoutDirection(Qt::RightToLeft);
label->setStyleSheet(QString::fromUtf8("background-color: rgb(179, 179, 179);\n""border-radius:4px;\n""padding:20px;"));
label->setAlignment(Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter);
gridLayout_2->addWidget(label, 1, 0, 1, 1);
horizontalLayout = new QHBoxLayout();
horizontalLayout->setObjectName(QString::fromUtf8("horizontalLayout"));
gridLayout = new QGridLayout();
gridLayout->setObjectName(QString::fromUtf8("gridLayout"));
pushButton = new QPushButton(centralwidget);
pushButton->setObjectName(QString::fromUtf8("pushButton"));
pushButton->setMinimumSize(QSize(0, 60));
pushButton->setMaximumSize(QSize(60, 60));
gridLayout->addWidget(pushButton, 0, 0, 1, 1);
pushButton_2 = new QPushButton(centralwidget);
pushButton_2->setObjectName(QString::fromUtf8("pushButton_2"));
pushButton_2->setMinimumSize(QSize(0, 60));
pushButton_2->setMaximumSize(QSize(60, 60));
gridLayout->addWidget(pushButton_2, 0, 1, 1, 1);
pushButton_3 = new QPushButton(centralwidget);
pushButton_3->setObjectName(QString::fromUtf8("pushButton_3"));
pushButton_3->setMinimumSize(QSize(0, 60));
pushButton_3->setMaximumSize(QSize(60, 60));
gridLayout->addWidget(pushButton_3, 0, 2, 1, 1);
pushButton_4 = new QPushButton(centralwidget);
pushButton_4->setObjectName(QString::fromUtf8("pushButton_4"));
pushButton_4->setMinimumSize(QSize(0, 60));
pushButton_4->setMaximumSize(QSize(60, 60));
gridLayout->addWidget(pushButton_4, 1, 0, 1, 1);
pushButton_5 = new QPushButton(centralwidget);
pushButton_5->setObjectName(QString::fromUtf8("pushButton_5"));
pushButton_5->setMinimumSize(QSize(0, 60));
pushButton_5->setMaximumSize(QSize(60, 60));
gridLayout->addWidget(pushButton_5, 1, 1, 1, 1);
pushButton_6 = new QPushButton(centralwidget);
pushButton_6->setObjectName(QString::fromUtf8("pushButton_6"));
pushButton_6->setMinimumSize(QSize(0, 60));
pushButton_6->setMaximumSize(QSize(60, 60));
gridLayout->addWidget(pushButton_6, 1, 2, 1, 1);
pushButton_7 = new QPushButton(centralwidget);
pushButton_7->setObjectName(QString::fromUtf8("pushButton_7"));
pushButton_7->setMinimumSize(QSize(0, 60));
pushButton_7->setMaximumSize(QSize(60, 60));
gridLayout->addWidget(pushButton_7, 2, 0, 1, 1);
pushButton_8 = new QPushButton(centralwidget);
pushButton_8->setObjectName(QString::fromUtf8("pushButton_8"));
pushButton_8->setMinimumSize(QSize(0, 60));
pushButton_8->setMaximumSize(QSize(60, 60));
gridLayout->addWidget(pushButton_8, 2, 1, 1, 1);
pushButton_9 = new QPushButton(centralwidget);
pushButton_9->setObjectName(QString::fromUtf8("pushButton_9"));
pushButton_9->setMinimumSize(QSize(0, 60));
pushButton_9->setMaximumSize(QSize(60, 60));
gridLayout->addWidget(pushButton_9, 2, 2, 1, 1);
horizontalLayout->addLayout(gridLayout);
verticalLayout = new QVBoxLayout();
verticalLayout->setObjectName(QString::fromUtf8("verticalLayout"));
verticalLayout->setContentsMargins(0, -1, -1, -1);
pushButton_15 = new QPushButton(centralwidget);
pushButton_15->setObjectName(QString::fromUtf8("pushButton_15"));
pushButton_15->setMinimumSize(QSize(0, 127));
pushButton_15->setMaximumSize(QSize(60, 152));
verticalLayout->addWidget(pushButton_15);
pushButton_10 = new QPushButton(centralwidget);
pushButton_10->setObjectName(QString::fromUtf8("pushButton_10"));
pushButton_10->setMinimumSize(QSize(0, 60));
pushButton_10->setMaximumSize(QSize(60, 60));
verticalLayout->addWidget(pushButton_10);
horizontalLayout->addLayout(verticalLayout);
verticalLayout_3 = new QVBoxLayout();
verticalLayout_3->setObjectName(QString::fromUtf8("verticalLayout_3"));
pushButton_12 = new QPushButton(centralwidget);
pushButton_12->setObjectName(QString::fromUtf8("pushButton_12"));
pushButton_12->setMinimumSize(QSize(0, 60));
pushButton_12->setMaximumSize(QSize(60, 60));
verticalLayout_3->addWidget(pushButton_12);
pushButton_11 = new QPushButton(centralwidget);
pushButton_11->setObjectName(QString::fromUtf8("pushButton_11"));
pushButton_11->setMinimumSize(QSize(0, 60));
pushButton_11->setMaximumSize(QSize(60, 60));
verticalLayout_3->addWidget(pushButton_11);
pushButton_14 = new QPushButton(centralwidget);
pushButton_14->setObjectName(QString::fromUtf8("pushButton_14"));
pushButton_14->setMinimumSize(QSize(0, 60));
pushButton_14->setMaximumSize(QSize(60, 60));
verticalLayout_3->addWidget(pushButton_14);
horizontalLayout->addLayout(verticalLayout_3);
verticalLayout_2 = new QVBoxLayout();
verticalLayout_2->setObjectName(QString::fromUtf8("verticalLayout_2"));
pushButton_17 = new QPushButton(centralwidget);
pushButton_17->setObjectName(QString::fromUtf8("pushButton_17"));
pushButton_17->setMinimumSize(QSize(0, 127));
pushButton_17->setMaximumSize(QSize(60, 152));
verticalLayout_2->addWidget(pushButton_17);
pushButton_13 = new QPushButton(centralwidget);
pushButton_13->setObjectName(QString::fromUtf8("pushButton_13"));
pushButton_13->setMinimumSize(QSize(0, 60));
pushButton_13->setMaximumSize(QSize(60, 60));
verticalLayout_2->addWidget(pushButton_13);
horizontalLayout->addLayout(verticalLayout_2);
gridLayout_2->addLayout(horizontalLayout, 2, 0, 1, 1);
MainWindow->setCentralWidget(centralwidget);
retranslateUi(MainWindow);
QObject::connect( pushButton , SIGNAL (clicked()), this , handleButton );
//this->handleButton();
// setupU
void Ui_MainWindow::retranslateUi(QMainWindow *MainWindow)
MainWindow->setWindowTitle(QApplication::translate("MainWindow", "DD | Calc", 0, QApplication::UnicodeUTF8));
label_2->setText(QApplication::translate("MainWindow", "DD - Calc", 0, QApplication::UnicodeUTF8));
label->setText(QApplication::translate("MainWindow", "0", 0, QApplication::UnicodeUTF8));
pushButton->setText(QApplication::translate("MainWindow", "1", 0, QApplication::UnicodeUTF8));
pushButton_2->setText(QApplication::translate("MainWindow", "2", 0, QApplication::UnicodeUTF8));
pushButton_3->setText(QApplication::translate("MainWindow", "3", 0, QApplication::UnicodeUTF8));
pushButton_4->setText(QApplication::translate("MainWindow", "4", 0, QApplication::UnicodeUTF8));
pushButton_5->setText(QApplication::translate("MainWindow", "5", 0, QApplication::UnicodeUTF8));
pushButton_6->setText(QApplication::translate("MainWindow", "6", 0, QApplication::UnicodeUTF8));
pushButton_7->setText(QApplication::translate("MainWindow", "7", 0, QApplication::UnicodeUTF8));
pushButton_8->setText(QApplication::translate("MainWindow", "8", 0, QApplication::UnicodeUTF8));
pushButton_9->setText(QApplication::translate("MainWindow", "9", 0, QApplication::UnicodeUTF8));
pushButton_15->setText(QApplication::translate("MainWindow", "=", 0, QApplication::UnicodeUTF8));
pushButton_10->setText(QApplication::translate("MainWindow", "0", 0, QApplication::UnicodeUTF8));
pushButton_12->setText(QApplication::translate("MainWindow", "-", 0, QApplication::UnicodeUTF8));
pushButton_11->setText(QApplication::translate("MainWindow", "+", 0, QApplication::UnicodeUTF8));
pushButton_14->setText(QApplication::translate("MainWindow", "/", 0, QApplication::UnicodeUTF8));
pushButton_17->setText(QApplication::translate("MainWindow", "C", 0, QApplication::UnicodeUTF8));
pushButton_13->setText(QApplication::translate("MainWindow", "x", 0, QApplication::UnicodeUTF8));
// retranslateUi
文件:window.h
#ifndef WINDOW_H
#define WINDOW_H
#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QGridLayout>
#include <QtGui/QHBoxLayout>
#include <QtGui/QHeaderView>
#include <QtGui/QLabel>
#include <QtGui/QMainWindow>
#include <QtGui/QPushButton>
#include <QtGui/QVBoxLayout>
#include <QtGui/QWidget>
#include <iostream>
QT_BEGIN_NAMESPACE
class Ui_MainWindow
private slots:
void handleButton();
public:
QWidget *centralwidget;
QGridLayout *gridLayout_2;
QLabel *label_2;
QLabel *label;
QHBoxLayout *horizontalLayout;
QGridLayout *gridLayout;
QPushButton *pushButton;
QPushButton *pushButton_2;
QPushButton *pushButton_3;
QPushButton *pushButton_4;
QPushButton *pushButton_5;
QPushButton *pushButton_6;
QPushButton *pushButton_7;
QPushButton *pushButton_8;
QPushButton *pushButton_9;
QVBoxLayout *verticalLayout;
QPushButton *pushButton_15;
QPushButton *pushButton_10;
QVBoxLayout *verticalLayout_3;
QPushButton *pushButton_12;
QPushButton *pushButton_11;
QPushButton *pushButton_14;
QVBoxLayout *verticalLayout_2;
QPushButton *pushButton_17;
QPushButton *pushButton_13;
void setupUi(QMainWindow *MainWindow);
void retranslateUi(QMainWindow *MainWindow);
;
// namespace Ui
// class MainWindow: public Ui_MainWindow ;
// // namespace Ui
QT_END_NAMESPACE
#endif // WINDOW_H
文件:main.cpp
#include <QApplication>
#include <QtCore/QVariant>
#include <iostream>
#include <window.h>
int main(int argc, char **argv)
QApplication app (argc, argv);
QMainWindow window;
Ui_MainWindow win;
win.setupUi(&window);
window.show();
return app.exec();
【问题讨论】:
【参考方案1】:连接的正确语法是这样的:
QObject::connect( pushButton , SIGNAL (clicked()), this , SLOT(handleButton()));
或新的函数指针语法(在 Qt5 中):
QObject::connect( pushButton , &QPushButton::clicked, this , Ui_MainWindow::handleButton);
但是你在那里做错了,你不应该修改类 UI_FormName
,因为当你在 Designer 中修改 .ui
文件时,该文件很可能会重新生成,请查看文档 here 以了解如何您可以在代码中使用uic
生成的代码。
LE:谢谢@MathiasSchmid
我没有注意到缺少宏,Q_OBJECT
宏需要添加到您的类的私有部分中才能使信号和插槽工作。
【讨论】:
我试过这个:QObject::connect( pushButton , &QPushButton::clicked(), this , Ui_MainWindow::handleButton);
但我得到了这个错误:error: cannot call member function ‘void QAbstractButton::clicked(bool)’ without object QObject::connect( pushButton , &QPushButton::clicked(), this , Ui_MainWindow::handleButton);
类定义 Ui_MainWindow
中缺少 Q_OBJECT
宏。并且UI_MainWindow
必须派生自QObject
或从QObject
派生的另一个类,然后它才能工作。
好的,所以我从 QObject
派生了类 Ui
类,并且代码确实可以编译,但现在我在运行时遇到错误:Object::connect: No such slot QObject::handleButton()
您需要Q_OBJECT
宏来在运行时解析信号槽连接。只需将 Q_OBJECT
作为 Ui_MainWindow 类定义的第一行。
更多关于 QOBJECT 宏的英特尔 here.以上是关于从 Qt 中的信号调用成员函数的问题的主要内容,如果未能解决你的问题,请参考以下文章