Qt-Qt使用回调函数方(callback)

实例代码：

.pro

1 QT       += core gui
 2 
 3 greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 4 
 5 CONFIG += c++11
 6 
 7 # The following define makes your compiler emit warnings if you use
 8 # any Qt feature that has been marked deprecated (the exact warnings
 9 # depend on your compiler). Please consult the documentation of the
10 # deprecated API in order to know how to port your code away from it.
11 DEFINES += QT_DEPRECATED_WARNINGS
12 
13 # You can also make your code fail to compile if it uses deprecated APIs.
14 # In order to do so, uncomment the following line.
15 # You can also select to disable deprecated APIs only up to a certain version of Qt.
16 #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
17 
18 SOURCES += \
19     main.cpp \
20     mainwindow.cpp
21 
22 HEADERS += \
23     mainwindow.h
24 
25 FORMS += \
26     mainwindow.ui
27 
28 # Default rules for deployment.
29 qnx: target.path = /tmp/$${TARGET}/bin
30 else: unix:!android: target.path = /opt/$${TARGET}/bin
31 !isEmpty(target.path): INSTALLS += target

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main.cpp

1 #include "mainwindow.h"
 2 
 3 #include <QApplication>
 4 
 5 int main(int argc, char *argv[])
 6 {
 7     QApplication a(argc, argv);
 8     MainWindow w;
 9     w.show();
10     return a.exec();
11 }

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mainwindow.h

1 #ifndef MAINWINDOW_H
 2 #define MAINWINDOW_H
 3 
 4 #include <QMainWindow>
 5 #include <QDebug>
 6 
 7 QT_BEGIN_NAMESPACE
 8 namespace Ui { class MainWindow; }
 9 QT_END_NAMESPACE
10 
11 typedef QString(*callBack)(QString str);// 函数指针
12 
13 // ******************调用类********************* //
14 class CallbackA
15 {
16 public:
17      void setCallBack(callBack callBackFunc);// 设置回调函数
18      callBack m_pCallBackFunc;// 回调函数成员
19 };
20 
21 // ******************被调类********************* //
22 class CallbackB
23 {
24 public:
25     static QString callBack(QString str);// 声明回调函数
26 };
27 
28 // ******************使用类********************* //
29 class MainWindow : public QMainWindow
30 {
31     Q_OBJECT
32 
33 public:
34     MainWindow(QWidget *parent = nullptr);
35     ~MainWindow();
36 
37 private:
38     Ui::MainWindow *ui;
39 };
40 #endif // MAINWINDOW_H

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mainwindow.cpp

1 #include "mainwindow.h"
 2 #include "ui_mainwindow.h"
 3 
 4 MainWindow::MainWindow(QWidget *parent)
 5     : QMainWindow(parent)
 6     , ui(new Ui::MainWindow)
 7 {
 8     ui->setupUi(this);
 9 
10     CallbackA *oCallbackAo = new CallbackA();
11     oCallbackAo->setCallBack(&CallbackB::callBack);// 运行后输出“CallbackB:callBack:  "CallbackA"”
12 }
13 
14 MainWindow::~MainWindow()
15 {
16     delete ui;
17 }
18 
19 
20 QString CallbackB::callBack(QString str)
21 {
22     qDebug() << "CallbackB:callBack: " << str;
23     return "CallbackB:callBack: ";
24 }
25 
26 void CallbackA::setCallBack(callBack callBackFunc)
27 {
28     m_pCallBackFunc = callBackFunc;
29     m_pCallBackFunc("CallbackA");
30 }

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mainwindow.ui

1 <?xml version="1.0" encoding="UTF-8"?>
 2 <ui version="4.0">
 3  <class>MainWindow</class>
 4  <widget class="QMainWindow" name="MainWindow">
 5   <property name="geometry">
 6    <rect>
 7     <x>0</x>
 8     <y>0</y>
 9     <width>358</width>
10     <height>169</height>
11    </rect>
12   </property>
13   <property name="windowTitle">
14    <string>MainWindow</string>
15   </property>
16   <widget class="QWidget" name="centralwidget"/>
17  </widget>
18  <resources/>
19  <connections/>
20 </ui>

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