QString exchange in qml through c++ - c++

Question

this example is supposed to read the string from TextInput and display it in another Rectangle on click of the mouse. However, it does not. Why?
//mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QDeclarativeView>
#include <QDeclarativeContext>
#include <QObject>
#include <QString>
class MainWindow : public QDeclarativeView
{
Q_OBJECT
public:
MainWindow(QWidget *parent = 0);
~MainWindow();
};
class Data : public QObject
{
Q_OBJECT
Q_PROPERTY(QString teamName READ getTeamName WRITE setTeamName NOTIFY nameChanged)
public:
Data(QObject *parent = 0);
~Data();
public:
QString getTeamName();
void setTeamName(QString &);
signals:
void nameChanged();
private:
QString n_teamName;
};
#endif // MAINWINDOW_H
//mainwindow.cpp
#include "mainwindow.h"
#include <QDeclarativeView>
#include <QDeclarativeContext>
#include <QString>
#include <QObject>
MainWindow::MainWindow(QWidget *parent)
: QDeclarativeView(parent)
{
}
MainWindow::~MainWindow()
{
}
Data::Data(QObject *parent) : QObject(parent)
{
//n_teamName = "Ahoj";
}
Data::~Data(){
}
QString Data::getTeamName(){
return n_teamName;
}
void Data::setTeamName(QString &newName){
if(newName != n_teamName){
n_teamName = newName;
emit nameChanged();
}
}
//main.cpp
#include "mainwindow.h"
#include <qdeclarative.h>
#include <QApplication>
#include <QDeclarativeView>
#include <QDeclarativeContext>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
Data d;
qmlRegisterType<Data>("NData", 1, 0, "Data");
w.rootContext()->setContextProperty("data", &d);
w.setSource(QUrl::fromLocalFile("../klik/Main.qml"));
w.show();
return a.exec();
}
//main.qml
// import QtQuick 1.0 // to target S60 5th Edition or Maemo 5
import QtQuick 1.1
import NData 1.0
Rectangle {
id: root
width: 600
height: 400
Rectangle{
id: text
...
TextInput{
anchors.fill: text
anchors.margins: 3
focus: true
}
}
Rectangle{
...
Text{
id: copyText
anchors.centerIn: copy
text: data.setTeamName()
}
}
Rectangle{
id: klik
...
MouseArea{
...
onClicked: {
copyText.text = data.teamName
}
}
}
}
It lets out the error: TypeError: Result of expression 'data.setTeamName' [undefined] is not a function.
Main.qml:51: Error: Cannot assign [undefined] to QString

Answer 1

teamName is a property of data, so simply use assign operator like data.teamName = 'some text';
Probably you should add id field to your TextInput like
TextInput{
id: textInput
anchors.fill: text
anchors.margins: 3
focus: true
}
And change onClicked, so
MouseArea{
...
onClicked: {
data.teamName = textInput.text
copyText.text = data.teamName // copyText.text = textInput.text is fine too
}
}

Answer 2

I believe your actual exception is due to the following line
text: data.setTeamName()
setTeamName is a private function on your data object, that is not exposed as a slot, and is thus undefined when called and assigned to text. Nevermind the fact that it makes no sense to call the set when you are performing an assignment. I'm assuming this was supposed to be data.getTeamName().