Summary of the use of qobjectcleanuphandler in QT

background

QObjectCleanupHandler Class for cleanup QObject Class object , It can usually be used as a resource Cleaner .

Monitor object lifecycle

①． summary

QObjectCleanupHandler The objects managed in are delete It will be automatically deleted from the managed image list , It can be used to monitor the life cycle of objects .

②． Code example

QtClassDemo * demo = new QtClassDemo(nullptr);
QObjectCleanupHandler  * demoWatch = new QObjectCleanupHandler;

connect(ui.pushButton, &QPushButton::clicked, [demo, demoWatch]() {
      
    demoWatch->add(demo);    
});

connect(ui.pushButton_2, &QPushButton::clicked, [demo, demoWatch]() {
    
    delete demo;
});

connect(ui.pushButton_3, &QPushButton::clicked, [demo, demoWatch]() {
    
    if (demoWatch->isEmpty())
    {
    
      qDebug() << " demo  have been deleted ";
    }
});

Automatic cleanup of objects

①． summary

QObjectCleanupHandler Objects are automatically destructed delete The objects it manages , It can be used for automatic deletion of dynamic objects .

②． Code example

connect(ui.pushButton, &QPushButton::clicked, [&]() {
    
  
    QObjectCleanupHandler objectHandler;
    objectHandler.add(new QtClassDemo("demo1"));
    objectHandler.add(new QtClassDemo("demo2"));
    objectHandler.add(new QtClassDemo("demo3"));
    objectHandler.add(new QtClassDemo("demo4"));  
});

Batch cleanup of dynamic objects

①． summary

QObjectCleanupHandler Of clear Method Society delete All the objects it manages , It can be used for batch deletion of dynamic objects .

②． Code example

connect(ui.pushButton, &QPushButton::clicked, [&]() {
    
  
  QObjectCleanupHandler * objectHandler = new QObjectCleanupHandler;
  objectHandler->add(new QtClassDemo("demo1"));
  objectHandler->add(new QtClassDemo("demo2"));
  objectHandler->add(new QtClassDemo("demo3"));
  objectHandler->add(new QtClassDemo("demo4"));

  objectHandler->clear();  
});