Receiving signals with arguments in QML from C++: Difference between revisions

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[[Category:snippets]]
{{Outdated|reason=Qt Quick 1}}
[[Category:Snippets::QML]]
The example code below shows how you can receive signals with arguments in QML from C++. The important thing to notice in the example is that the signal's argument needs to be named identically in QML and in C++. So in this example it needs to be referred to as "text" both places, otherwise you will receive errors.


= Receiving signals with arguments in QML from C++ =
main.cpp
 
The example code below shows how you can receive signals with arguments in QML from C+''. The important thing to notice in the example is that the signal's argument needs to be named identically in QML and in C''+. So in this example it needs to be referred to as "text" both places, otherwise you will receive errors.


main.cpp
<code>
<code>
#include <QtGui>
#include <QtGui>
Line 14: Line 13:
  Q_OBJECT
  Q_OBJECT
public:
public:
 
Q_INVOKABLE void triggerEvent(QString text) {
Q_INVOKABLE void triggerEvent(QString text)
  emit somethingHappened(text);
{
emit somethingHappened(text);
  }
  }
  Person()
  Person() {
{
  startTimer(1000);
startTimer(1000);
  }
  }
  void timerEvent(QTimerEvent '''e)
  void timerEvent(QTimerEvent *e) {
{
  QString text = "The text";
QString text = "The text";
  triggerEvent(text);
triggerEvent(text);
  }
  }
signals:
signals:
Line 33: Line 28:


#include "main.moc"
#include "main.moc"
int main(int argc, char'''* argv)
 
int main(int argc, char** argv)
{
{
  QApplication app(argc, argv);
  QApplication app(argc, argv);
Line 44: Line 40:
}
}
</code>
</code>
main.qml
main.qml
<code>
<code>
import People 1.0
import People 1.0
Line 52: Line 50:
  id: myPerson
  id: myPerson
  onSomethingHappened: {
  onSomethingHappened: {
console.log(" something happened " +text);
  console.log(" something happened " +text);
  }
  }
}
}
</code>

Latest revision as of 13:07, 28 November 2016

IMPORTANT: The content of this page is outdated. Reason: Qt Quick 1
If you have checked or updated this page and found the content to be suitable, please remove this notice.

The example code below shows how you can receive signals with arguments in QML from C++. The important thing to notice in the example is that the signal's argument needs to be named identically in QML and in C++. So in this example it needs to be referred to as "text" both places, otherwise you will receive errors.

main.cpp

#include <QtGui>
#include <QtDeclarative>

class Person : public QObject
{
 Q_OBJECT
public:
 Q_INVOKABLE void triggerEvent(QString text) {
  emit somethingHappened(text);
 }
 Person() {
  startTimer(1000);
 }
 void timerEvent(QTimerEvent *e) {
  QString text = "The text";
  triggerEvent(text);
 }
signals:
 void somethingHappened(QString text);
};

#include "main.moc"

int main(int argc, char** argv)
{
 QApplication app(argc, argv);
 qmlRegisterType<Person>("People", 1, 0, "Person");
 QDeclarativeView view;
 view.setSource(QUrl::fromLocalFile("main.qml"));
 view.resize(200,100);
 view.show();
 return app.exec();
}

main.qml

import People 1.0
import QtQuick 1.0

Person {
 id: myPerson
 onSomethingHappened: {
  console.log(" something happened " +text);
 }
}