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7. Graph Event Handling

        Graph event handling in JFDraw.

    We added a new graph event handling mechanism in JFDraw now. So you can implement you own code while a shape/selection is selected, moving/moved,moving/moved nodes, changed properties.

        Sample codes of graph event handling.

Method 1: add an Event Listener to current DrawPane.

//Action: create a draw panel
//Desc: A DrawPane object packaged a vertical ruler, a horizontal ruler and a drawing canvas
DrawPane panel =new DrawPane();

//Action: Add a new customized Graph event listener for JFDraw shapes.
panel.addGraphEventListener(new GraphEventListener(){
    public void graphChanged(GraphEvent ge){
        Sample5.printGraphChangedEvent(ge);
}
});

Method 2: Create a subclass which extends DrawPane and implements GraphEventListener.

//you can use method below to create a sub class object of DrawPane
DrawPane panel =new MyDrawPane();

....

class MyDrawPane extends DrawPane implements GraphEventListener{
    public void graphChanged(GraphEvent ge){
        Sample5.printGraphChangedEvent(ge);
}
}

 

         Output samples in Sample5.printGraphChangedEvent method.

    Lines below are some sample output for Sample5.printGraphChangedEvent Method:

.........

Event: Shape Selected; Shape Count:1; mouse Pos:163,126
Event: Shape Moving; Shape Count:1; mouse Pos:163,124
Event: Shape Moving; Shape Count:1; mouse Pos:163,122
Event: Shape Moving; Shape Count:1; mouse Pos:163,120
Event: Shape Moving; Shape Count:1; mouse Pos:165,120
Event: Shape Moving; Shape Count:1; mouse Pos:165,118
Event: Shape Moving; Shape Count:1; mouse Pos:165,116
Event: Shape Moving; Shape Count:1; mouse Pos:167,116
Event: Shape Moving; Shape Count:1; mouse Pos:167,114
Event: Shape Moved; Shape Count:1; mouse Pos:167,114
Event: Node Selected; Shape Count:1; mouse Pos:203,146
Event: Node Moving; Shape Count:1; mouse Pos:203,144
Event: Node Moving; Shape Count:1; mouse Pos:201,144
Event: Node Moving; Shape Count:1; mouse Pos:199,144
Event: Node Moving; Shape Count:1; mouse Pos:197,144
Event: Node Moving; Shape Count:1; mouse Pos:195,142
Event: Node Moving; Shape Count:1; mouse Pos:193,142
Event: Node Moving; Shape Count:1; mouse Pos:193,140
Event: Node Moving; Shape Count:1; mouse Pos:191,140
Event: Node Moving; Shape Count:1; mouse Pos:191,138   

.........

        To get full source code of this sample.

    You can download the full sample source code package here. Then open the file at sample5/Sample5.java for detail informations.

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