signal and slot

[Devoraz]

i connect this in a (lets say setting.cpp), the slot is in another (lets say node.cpp)

connect(ui.EDnameTxt, SIGNAL(textChanged(QString)), Node, SLOT(setText(QString)));

connect(ui.EDnameTxt, SIGNAL(textChanged(QString)), Node, SLOT(setText(QString)));

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but when i compile it give me this error,

1>.\settingswindow.cpp(57) : error C2275: 'Node' : illegal use of this type as an expression
1> c:\texas instruments\node.h(62) : see declaration of 'Node'

whats wrong with the declartion of my node.h???

class Node : public QGraphicsItem, public QObject
{
	Q_OBJECT
 
public:
    typedef enum{ACCESS_POINT, END_DEVICE}NODE_TYPE;
    typedef struct
    {
        NODE_TYPE	type;
        int			addr;
        int			xPos;
        int			yPos;
		int			strength;
        float		temp;
        float		voltage;
		int			re;
 
		int			t_time_on;
		int			fadeNumber;
		int			fadeTime;
		int			newNode;
		int			deletedNode;
 
    }NODE_DATA;
 
		QBrush fill[40];
    Node(NetworkView *networkView);
	NODE_DATA nodeData;
    void addEdge(Edge *edge);
    QList<Edge *> edges() const;
 
    enum { Type = UserType + 1 };
    int type() const { return Type; }
 
    bool advance();
 
    QRectF boundingRect() const;
    QPainterPath shape() const;  
	void EDnamePreset();
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
 
 
    void setNodeData(int index);
    void updateData(int index);
	void AlertMessage();
    int getElapsedTime();
    void removeEdge(int childAddr = 0);
    int getAddr() { return nodeData.addr; }
    float getTemp() { return nodeData.temp; }
    int getType() { return nodeData.type; }
    void setTempUnit();
    void setColor(const NODE_TYPE type);
	int Node::find_active_node();
	void Node::current_updateData(int index);
 
	int timerId () const; 
 
	/*struct colors{
		int alpha;
		int r;
		int g;
		int b;
		int newnodeflag;
		int delnodeflag;
	};
	struct colors node_colors[100];*/
public slots:
	void EDnameChanged(int);
	void setText(const QString &newText){text = newText;}
 
protected:
    QVariant itemChange(GraphicsItemChange change, const QVariant &value);
 
    void timerEvent(QTimerEvent *);
 
   // NODE_DATA nodeData;
 
private:
	Ui_SettingsWindow ui;
    QList<Edge *> edgeList;
    QPointF newPos;
    NetworkView *graph;
	QPixmap pixmap,alpha_pix,back_pix,pixmap2,pix;
 
    QColor nodeColor;
    QColor nodeColorDark;
	QColor AlertColor;
	QColor AlertColorDark;
	QColor DisAlertColorDark;
	QColor DisAlertColor;
 
	QFont modeFont;
	QFont addrFont;
	QFont tempFont;
	QFont battFont;
	QFont strengthFont;
    QFont timeFont;
	QFont end_deviceFont;
	QFont keyFont;
	QFont smallFont;
	QFont txFont;
 
    QTime timeStamp;
	QDate dateStamp;
 
    NodeDb *pNodeDb;
 
    // Flag used to highlight node.
    bool updated;
    int updateTimerId,fade_speed,updateTimerId2,updateTimerId3;
 
    bool celsius;
	qreal arrowSize;
	double alertTemp;
	int alertDistance;
	int edStrength;
	QString nodeName;
	QString EDname;
	QString text;
	QString EDnameText;
};

class Node : public QGraphicsItem, public QObject
{
	Q_OBJECT

public:
    typedef enum{ACCESS_POINT, END_DEVICE}NODE_TYPE;
    typedef struct
    {
        NODE_TYPE	type;
        int			addr;
        int			xPos;
        int			yPos;
		int			strength;
        float		temp;
        float		voltage;
		int			re;
		
		int			t_time_on;
		int			fadeNumber;
		int			fadeTime;
		int			newNode;
		int			deletedNode;
		
    }NODE_DATA;

		QBrush fill[40];
    Node(NetworkView *networkView);
	NODE_DATA nodeData;
    void addEdge(Edge *edge);
    QList<Edge *> edges() const;
	
    enum { Type = UserType + 1 };
    int type() const { return Type; }

    bool advance();

    QRectF boundingRect() const;
    QPainterPath shape() const;  
	void EDnamePreset();
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);


    void setNodeData(int index);
    void updateData(int index);
	void AlertMessage();
    int getElapsedTime();
    void removeEdge(int childAddr = 0);
    int getAddr() { return nodeData.addr; }
    float getTemp() { return nodeData.temp; }
    int getType() { return nodeData.type; }
    void setTempUnit();
    void setColor(const NODE_TYPE type);
	int Node::find_active_node();
	void Node::current_updateData(int index);

	int timerId () const; 

	/*struct colors{
		int alpha;
		int r;
		int g;
		int b;
		int newnodeflag;
		int delnodeflag;
	};
	struct colors node_colors[100];*/
public slots:
	void EDnameChanged(int);
	void setText(const QString &newText){text = newText;}

protected:
    QVariant itemChange(GraphicsItemChange change, const QVariant &value);

    void timerEvent(QTimerEvent *);
	
   // NODE_DATA nodeData;
   
private:
	Ui_SettingsWindow ui;
    QList<Edge *> edgeList;
    QPointF newPos;
    NetworkView *graph;
	QPixmap pixmap,alpha_pix,back_pix,pixmap2,pix;

    QColor nodeColor;
    QColor nodeColorDark;
	QColor AlertColor;
	QColor AlertColorDark;
	QColor DisAlertColorDark;
	QColor DisAlertColor;

	QFont modeFont;
	QFont addrFont;
	QFont tempFont;
	QFont battFont;
	QFont strengthFont;
    QFont timeFont;
	QFont end_deviceFont;
	QFont keyFont;
	QFont smallFont;
	QFont txFont;

    QTime timeStamp;
	QDate dateStamp;

    NodeDb *pNodeDb;

    // Flag used to highlight node.
    bool updated;
    int updateTimerId,fade_speed,updateTimerId2,updateTimerId3;

    bool celsius;
	qreal arrowSize;
	double alertTemp;
	int alertDistance;
	int edStrength;
	QString nodeName;
	QString EDname;
	QString text;
	QString EDnameText;
};

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[yogeshgokul]

i connect this in one .cpp

connect(ui.EDnameTxt, SIGNAL(textChanged(QString)), Node, SLOT(setText(QString)));

connect(ui.EDnameTxt, SIGNAL(textChanged(QString)), Node, SLOT(setText(QString)));

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You have to pass the address of object of Node class. Not Node class itself.
Like this:

Node nodeObj;
connect(ui.EDnameTxt, SIGNAL(textChanged(QString)), &nodeObj, SLOT(setText(QString)));

Node nodeObj;
connect(ui.EDnameTxt, SIGNAL(textChanged(QString)), &nodeObj, SLOT(setText(QString)));

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[Devoraz]

You have to pass the address of object of Node class. Not Node class itself.
Like this:

Node nodeObj;
connect(ui.EDnameTxt, SIGNAL(textChanged(QString)), &nodeObj, SLOT(setText(QString)));

Node nodeObj;
connect(ui.EDnameTxt, SIGNAL(textChanged(QString)), &nodeObj, SLOT(setText(QString)));

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i tried ur way, but it give em the following error....

1>.\settingswindow.cpp(57) : error C2512: 'Node' : no appropriate default constructor available

[yogeshgokul]

i tried ur way, but it give em the following error....1>.\settingswindow.cpp(57) : error C2512: 'Node' : no appropriate default constructor available

OMG !!!
That was an example. Please create instance of Node class according to available constructors. You have to pass this

NetworkView *networkView

NetworkView *networkView

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in constructor.

Or create a default constructor.