使用 Q_INVOKABLE 将 C++ 与 QML 连接起来
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Connecting C++ with QML using Q_INVOKABLE
提问by user123_456
I have a Qt function:
我有一个 Qt 函数：
void MainWindow::button_clicked(Qstring a, Qstring b, Qstring c, Qstring d)
I collect data from QML and I want to pass data to this function which is in Qt. So I know I need to use Q_INVOKABLEbut don't know really how to use it.
我从 QML 收集数据，我想将数据传递给 Qt 中的这个函数。所以我知道我需要使用Q_INVOKABLE但不知道如何使用它。
And one more thing is it possible to invoke some other function when invoke this certain above.
For example: I invoke the above function but in her body I invoke refresh()function. Is this possible?
还有一件事是在调用上面的某个函数时可以调用其他一些函数。
例如：我调用了上面的函数，但在她的身体中我调用了refresh()函数。这可能吗？
回答by Frank Osterfeld
To be able to call a method from QML, you must either mark it with Q_INVOKABLE or as a slot. I prefer Q_INVOKABLE if it's not meant to be used as a slot, as its more minimal.
为了能够从 QML 调用方法，您必须使用 Q_INVOKABLE 或作为槽标记它。如果不打算用作插槽，我更喜欢 Q_INVOKABLE，因为它更小。
class MainWindow : public QMainWindow {
Q_OBJECT
public:
...
Q_INVOKABLE void buttonClicked( const QString& a, const QString& b, const QString& c, const QString& d );
....
};
void MainWindow::buttonClicked( const QString& a, const QString& b, const QString& c, const QString& d ) {
...do stuff
update(); //example
}
The implementation of buttonClicked() can contain any C++ code.
buttonClicked() 的实现可以包含任何 C++ 代码。
To make the main window instance accessible from QML, you must register it, e.g.
要从 QML 访问主窗口实例，您必须注册它，例如
QDeclarativeView* view = ...your view
view->rootContext()->setContextProperty( "_mainWindow", mainWindow );
Once registered, you can call buttonClicked from QML:
注册后，您可以从 QML 调用 buttonClicked：
_mainWindow.buttonClicked("foo", "bar", "c", "d")
