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QT笔记——QT类反射机制简单学习

2022-08-02 10:59:00 【旧街凉风°】

学习 QT的类反射机制

使用Qt 反射机制的条件

1.需要继承自QObject 类或者它的派生类，并需要在类中加入Q_OBJECT 宏
2.注册成员函数：若希望普通成员函数能够被反射，需要在函数声明之前加入Q_INVOKABLE 宏。
3.注册成员变量：若希望成员变量能被反射，需要使用Q_PROPERTY 宏。
4.注册枚举变量：若希望枚举能被反射，需要使用Q_ENUM 或者 Q_FLAGS宏。

在这里插入图片描述

QMetaObjectTest.h

#pragma once

#include <QtWidgets/QWidget>
#include "ui_QMetaObjectTest.h"
#include <QMetaObject>
#include <QDebug>

class QMetaObjectTest : public QWidget
{
    
    Q_OBJECT
    Q_CLASSINFO("author", "lion_cxq")   
    Q_PROPERTY(QString m_name READ getName WRITE setName)
public:
     Q_INVOKABLE  QMetaObjectTest(QWidget *parent = Q_NULLPTR);
     enum PriorityType{
     
         High,
         Low, 
         VeryHigh,
         VeryLow 
     };
     Q_ENUM(PriorityType)
     Q_INVOKABLE void setName(QString name);
     Q_INVOKABLE QString getName();
     Q_INVOKABLE void testMessage(int a ,int b);
private:
    Ui::QMetaObjectTestClass ui;
	QString m_name;
};

QMetaObjectTest.cpp

#include "QMetaObjectTest.h"

QMetaObjectTest::QMetaObjectTest(QWidget *parent)
    : QWidget(parent)
{
    
    ui.setupUi(this);
}

void QMetaObjectTest::testMessage(int a,int b)
{
    
    qDebug() <<QStringLiteral("参数一:") << a<< QStringLiteral("参数二:") << b;
}

void QMetaObjectTest::setName(QString name)
{
    
    m_name = name;
}

QString QMetaObjectTest::getName()
{
    
    return m_name;
}

main.cpp

#include "QMetaObjectTest.h"
#include <QtWidgets/QApplication>
#include <QMetaObject>
#include <QMetaMethod>
#include <QDebug>
#include <QMetaProperty>

int main(int argc, char *argv[])
{
    
    QApplication a(argc, argv);

   QMetaObjectTest object;
   const QMetaObject* theMetaObject = object.metaObject();
   
   //该类的类名
   qDebug() <<QStringLiteral("类名：") << theMetaObject->className();

   //该类注册的信息
   int  classInfoIndex;
   int classInfoCount = theMetaObject->classInfoCount();
   for (classInfoIndex = 0; classInfoIndex < classInfoCount; ++classInfoIndex)
   {
    
	   QMetaClassInfo classInfo = theMetaObject->classInfo(classInfoIndex);
	   qDebug() << "name: " << classInfo.name() << " " << "value: " << classInfo.value();
   }
   
	//该类的成员
   int metathodIndex;
   int metathodCount = theMetaObject->methodCount();
   for (metathodIndex = 0; metathodIndex < metathodCount; ++metathodIndex)
   {
    
	   QMetaMethod oneMethod = theMetaObject->method(metathodIndex);
	   qDebug() << "typeName: " << oneMethod.typeName()<<" "<< "methodType: " << oneMethod.methodType()<<" "<<"parameterNames: " << oneMethod.parameterNames();
   }

   //该类的 属性
   int propertyIndex;
   int propertyCount = theMetaObject->propertyCount();
   for (propertyIndex = 0; propertyIndex < propertyCount; ++propertyIndex)
   {
    
	   QMetaProperty oneProperty = theMetaObject->property(propertyIndex);
	   qDebug() << "name: " << oneProperty.name()<<" "<<"type: " << oneProperty.type();
   }

   //该对象的 枚举集合
   int enumeratorIndex;
   int enumeratorCount = theMetaObject->enumeratorCount();
   for (enumeratorIndex = 0; enumeratorIndex < enumeratorCount; ++enumeratorIndex)
   {
    
	   QMetaEnum oneEnumerator = theMetaObject->enumerator(enumeratorIndex);
	   int enumIndex;
	   int enumCount = oneEnumerator.keyCount();
	   for (enumIndex = 0; enumIndex < enumCount; ++enumIndex)
	   {
    
		   qDebug() << oneEnumerator.key(enumIndex) << " ==> " << oneEnumerator.value(enumIndex);
	   }
   }

   //获取该类的静态元对象 调用 并且实例化一个对象(我们并没有new它)
   QMetaObject metaObj = QMetaObjectTest::staticMetaObject;
   QObject* obj = metaObj.newInstance();
   QMetaObjectTest* metaObjectTest= qobject_cast<QMetaObjectTest*>(obj);
   metaObjectTest->testMessage(10, 20);
   
    return a.exec();
}