第16课 Qt对象间的父子关系

#include <QApplication>
#include <QString>
#include <QDebug>//father-children测试
void fcTest()
{
    QObject* p = new QObject(); //只有QObject及子孙类之间才能够成父子关系
    QObject* c1 = new QObject();
    QObject* c2 = new QObject();
    
    c1->setParent(p);
    c2->setParent(p);
    
    //1.先打印c1和c2两个对象的地址
    qDebug() << "c1: " << c1; //打印c1的地址
    qDebug() << "c2: " << c2; //打印c2的地址

    //2.输出：通过p，输出其两个孩子的地址（期待结果为c1和c2）
    const QObjectList& list = p->children();
    for(int i = 0; i < list.length(); i++)
    {
        qDebug() << list[i];
    }

    qDebug() <<"p: " << p; //输出p的地址

    qDebug() << "c1->parent：" << c1->parent();
    qDebug() << "c2->parent: " << c2->parent();
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    
    fcTest();
      
    return a.exec();
}

#include <QApplication>
#include <QString>
#include <QDebug>

//Qt对象要从QObject中继承下来
class MObj: public QObject
{
    QString m_name;
public:
    MObj(const QString& name)
    {
        m_name = name;
        
        qDebug() << "Constructor:" << this << m_name;
    }
    
    ~MObj(){ qDebug() << "Destructor:" << this << m_name;}
};

//删除对象树某节点
void delTest()
{
    MObj* obj1 = new MObj("obj1");
    MObj* obj2 = new MObj("obj2");
    MObj* obj3 = new MObj("obj3");
    MObj* obj4 = new MObj("obj4");
    
    obj2->setParent(obj1);
    obj3->setParent(obj1);
    obj4->setParent(obj3);
    
    delete obj3; //删除obj3,会同时删除其孩子并将其从父对象链表中移除！

    const QObjectList& list = obj1->children();

    qDebug()<< "obj2: " << obj2;

    for(int i = 0; i < list.length(); i++)
    {
        qDebug() << list[i]; //obj1的孩子只剩obj2
    }
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    
    delTest();
      
    return a.exec();
}