QT信号连接信号

2024-05-31 05:26| 来源: 网络整理| 查看: 265

有时候代码可能复杂，我们需要一个信号连接另一个信号，比如例子中的下课不是直接运行时触发的，而是点击下课按钮

#include "mainwindow.h" #include "ui_mainwindow.h" #include "QPushbutton.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); //创建一个老师对象 this->tc = new Teacher(this); //创建一个学生对象 this->st = new Student(this); void(Teacher::*teachersignal2)(void) = &Teacher::Hungry; void(Student::*studentslot2)(void) = &Student::Treat; connect(tc,teachersignal, st, studentslot); QPushButton *btn = new QPushButton("下课",this); this->resize(600,400); connect(tc,teachersignal2, st, studentslot2); connect(btn,&QPushButton::clicked,tc,teachersignal2); } MainWindow::~MainWindow() { delete ui; }

扩展内容

断开信号使用disconnect(tc,teachersignal2, st, studentslot2); 一个信号可以连接多个槽函数多个信号可以连接一个槽函数

在teacher类加入一个crying信号

#ifndef TEACHER_H #define TEACHER_H #include class Teacher : public QObject { Q_OBJECT public: explicit Teacher(QObject *parent = nullptr); signals: void Hungry(); void Hungry(QString foodName); void Crying(); //老师感动哭了 }; #endif // TEACHER_H # void(Teacher::*teachersignal)(QString) = &Teacher::Hungry; void(Student::*studentslot)(QString) = &Student::Treat; void(Teacher::*teachersignal2)(void) = &Teacher::Hungry; void(Student::*studentslot2)(void) = &Student::Treat; void(Teacher::*teachersignal3)(void) = &Teacher::Crying; connect(tc,teachersignal, st, studentslot); //classIsOver(); QPushButton *btn = new QPushButton("下课",this); this->resize(600,400); //connect(btn,&QPushButton::clicked,this,&MainWindow::classIsOver); connect(tc,teachersignal2, st, studentslot2); connect(tc,teachersignal3, st, studentslot2); connect(btn,&QPushButton::clicked,tc,teachersignal2); connect(btn,&QPushButton::clicked,tc,teachersignal3);

代码中我使用qpushbutton触发了两个信号，同理我也可以使用不同信号触发同一个槽函数

信号和槽函数的参数必须一一对应信号参数个数可以多余槽的参数个数，但类型要一一对应

Qt4版本以前的信号与槽的连接连接无参 connect(tc,SIGNAL(Hungry()),st,SLOT(Treat())); 优点，参数直观。缺点，类型不做检测（编译不做检测，运行报错）

Qt5以上支持Qt4的写法，反之不支持。

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QT信号连接信号

QT信号连接信号

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