How to pass a function "pointer" from JavaScript to a slot?
in JavaScript:
function f1()
{
alert("f1");
}
qtclass.submit(f1);
and in Qt:
public slots:
void submit(void * ptr)
{
(void)ptr;
}
I need the "f1", function to get fired in the JavaScript from the c++, once some processing is done. Also I do not know in advance the name of the function pointer.
On
While it wouldn't work in all cases, you could simply pass a string to your slot. Your slot could then use evaluateJavaScript (as serge has suggested) to call the function.
function f1()
{
alert("f1");
}
qtclass.submit("f1");
and in Qt:
public slots:
void submit(QString functionName)
{
m_pWebView->page()->mainFrame()->evaluateJavaScript(functionName + "()");
}
You could solve this in another way, by using Qt signals, as follows:
class qtclass
{
signals:
void done(QString message);
};
In your HTML file you can connect to this signal, like this:
qtclass.done.connect(f1);
function f1(message)
{
alert('f1 called from qtclass with message' + message);
}
Then you C++ class does not need to know about the javascript function.
On
I have one entire working solution here - using slots. However, I couldn't get the signals working as suggested by Kurt.
#include <QtGui/QApplication>
#include <QApplication>
#include <QDebug>
#include <QWebFrame>
#include <QWebPage>
#include <QWebView>
class MyJavaScriptOperations : public QObject {
Q_OBJECT
public:
QWebView *view;
MyJavaScriptOperations();
Q_INVOKABLE qint32 MultOfNumbers(int a, int b) {
qDebug() << a * b;
return (a*b);
}
public slots:
void callback();
public:
void firecb();
signals:
void done();
};
MyJavaScriptOperations::MyJavaScriptOperations()
{
view = new QWebView();
view->resize(400, 500);
connect(view->page()->mainFrame(), SIGNAL(javaScriptWindowObjectCleared()), this, SLOT(callback()));
view->load(QUrl("./shreyas.html"));
view->show();
qDebug()<<view;
}
void MyJavaScriptOperations::callback()
{
qDebug()<<"Sending hello text";
QString function = "f1()";
view->page()->mainFrame()->addToJavaScriptWindowObject("myoperations", this);
view->page()->mainFrame()->evaluateJavaScript("f1()");
done();
}
void MyJavaScriptOperations::firecb()
{
qDebug()<<"Emitting Signal";
done();
}
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MyJavaScriptOperations *jvs = new MyJavaScriptOperations;
jvs->firecb();
return a.exec();
}
#include "main.moc"
The html file changes are -
<head>
<script LANGUAGE="JavaScript">
function f1()
{
alert('f1 called from qtclass with message');
document.write("HELLLLLLLLL");
}
myoperations.callback(f1);
function f2()
{
var result = myoperations.MultOfNumbers(3,7);
document.write(result);
alert('f1 called from qtclass with message');
}
function f3()
{
alert('f3');
}
myoperations.done.connect(f3);
</script>
</head>
<body>
test html
<input type="button" value="click" onclick="f2()">
</body>
you should be able to execute your script using QWebFrame::evaluateJavaScript method. See if an example below would work for you:
initializing webview:
loadFinished signal handler:
test.html:
evaluateJavaScript should trigger an alert message box and return QVariant with f1 function result.
hope this helps, regards