C++ Qt：如何处理用户按下“X”（关闭）按钮的事件？
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Qt: How do I handle the event of the user pressing the 'X' (close) button?
提问by The Peaceful Coder
I am developing an application using Qt. I don't know which slot corresponds to the event of "the user clicking the 'X'(close) button of the window frame" i.e. this button:
我正在使用 Qt 开发应用程序。我不知道哪个插槽对应于“用户单击窗口框架的'X'（关闭）按钮”的事件，即这个按钮：
If there isn't a slot for this, can anyone suggest me some other method by which I can start a function after the user presses that close button.
如果没有用于此的插槽，任何人都可以向我建议一些其他方法，以便在用户按下关闭按钮后我可以启动功能。
回答by asclepix
If you have a QMainWindowyou can override closeEventmethod.
如果你有一个QMainWindow你可以覆盖的closeEvent方法。
#include <QCloseEvent>
void MainWindow::closeEvent (QCloseEvent *event)
{
QMessageBox::StandardButton resBtn = QMessageBox::question( this, APP_NAME,
tr("Are you sure?\n"),
QMessageBox::Cancel | QMessageBox::No | QMessageBox::Yes,
QMessageBox::Yes);
if (resBtn != QMessageBox::Yes) {
event->ignore();
} else {
event->accept();
}
}
If you're subclassing a QDialog, the closeEventwill not be called and so you have to override reject():
如果您子类化 a QDialog，closeEvent则不会调用 ，因此您必须覆盖reject()：
void MyDialog::reject()
{
QMessageBox::StandardButton resBtn = QMessageBox::Yes;
if (changes) {
resBtn = QMessageBox::question( this, APP_NAME,
tr("Are you sure?\n"),
QMessageBox::Cancel | QMessageBox::No | QMessageBox::Yes,
QMessageBox::Yes);
}
if (resBtn == QMessageBox::Yes) {
QDialog::reject();
}
}
回答by The Peaceful Coder
Well, I got it. One way is to override the QWidget::closeEvent(QCloseEvent *event)method in your class definition and add your code into that function. Example:
嗯，我明白了。一种方法是覆盖类定义中的方法并将代码添加到该函数中。例子：QWidget::closeEvent(QCloseEvent *event)
class foo : public QMainWindow
{
Q_OBJECT
private:
void closeEvent(QCloseEvent *bar);
// ...
};
void foo::closeEvent(QCloseEvent *bar)
{
// Do something
bar->accept();
}
回答by Sebastian Lange
You can attach a SLOT to the
您可以将 SLOT 连接到
void aboutToQuit();
signal of your QApplication. This signal should be raised just before app closes.
QApplication 的信号。这个信号应该在应用程序关闭之前发出。
回答by Alexander
also you can reimplement protected member QWidget::closeEvent()
你也可以重新实现受保护的成员 QWidget::closeEvent()
void YourWidgetWithXButton::closeEvent(QCloseEvent *event)
{
// do what you need here
// then call parent's procedure
QWidget::closeEvent(event);
}
