是否可以将信号连接到静态插槽而不使用接收器实例？ [英] Is it possible to connect a signal to a static slot without a receiver instance?

问题描述

是否可以将信号连接到静态槽而不使用接收器实例？

像这样： connect（& object，SIGNAL （））; STATIC_SLOT（staticFooMember（）））;

有一个 QApplication :: closeAllWindows / code> function with [static slot] attribute in Qt documentation。有一个使用文档的示例：

  exitAct = new QAction（tr（E& xit这个）; 
 exitAct-> setShortcuts（QKeySequence :: Quit）; 
 exitAct-> setStatusTip（tr（退出应用程序））; 
 connect（exitAct，SIGNAL（triggered（）），qApp，SLOT（closeAllWindows（）））; 
  

是否允许执行相同的操作，但不传递实例变量静态函数）？

  class Some：public QObject {
 Q_OBJECT 
 public slots：
 static void foo（）; 
 private：
 Some（）; 
}; 
  





---

也许Frank Osterfeld是对的，在这种情况下使用单例模式，但我仍然惊讶为什么此功能尚未实现

更新：
$ b

在Qt 5中，可以。

解决方案

不允许。相反，允许使用作为静态函数的插槽，但是为了能够连接它，您需要一个实例。

在他们的例子中，

  connect（exitAct，SIGNAL （）），qApp，SLOT（closeAllWindows（）））; 
  

表示比以前调用

  QApplication * qApp = QApplication :: instance（）; 
  

编辑：

连接对象是函数

  bool QObject :: connect（const QObject * sender，const QMetaMethod& signal，const QObject * receiver ，const QMetaMethod& method，Qt :: ConnectionType type = Qt :: AutoConnection）
  

要删除 const QObject * receiver ？

检查 moc 文件，它自己说。

Is it possible to connect a signal to static slot without receiver instance?

Like this: connect(&object, SIGNAL(some()), STATIC_SLOT(staticFooMember()));

There is a QApplication::closeAllWindows() function with [static slot] attribute in Qt documentation. And there is an example of using it from the documentation:

exitAct = new QAction(tr("E&xit"), this);
exitAct->setShortcuts(QKeySequence::Quit);
exitAct->setStatusTip(tr("Exit the application"));
connect(exitAct, SIGNAL(triggered()), qApp, SLOT(closeAllWindows()));

Is it allowed to do the same action but without passing an instance variable (e.g. when a class has only static functions)?

class Some : public QObject {
    Q_OBJECT
public slots:
    static void foo();
private:
    Some();
};

---

Maybe Frank Osterfeld is right and it is better to use singleton pattern in this case but I am still surprised why this feature has not been implemented yet.

Update:

In Qt 5 it is possible.

解决方案

No it is not allowed. Rather, it is allowed to use a slot which is a static function, but to be able to connect it you need an instance.

In their example,

connect(exitAct, SIGNAL(triggered()), qApp, SLOT(closeAllWindows()));

means than they previously called

QApplication* qApp = QApplication::instance();

Edit:

The only interface for connecting object is the function

bool QObject::connect ( const QObject * sender, const QMetaMethod & signal, const QObject * receiver, const QMetaMethod & method, Qt::ConnectionType type = Qt::AutoConnection )

How are you going to get rid of const QObject * receiver?

Check the moc files in your project, it speaks by itself.

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