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Thread: Throwing an Exception in paintComponent

  1. #1
    Junior Member
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    Default Throwing an Exception in paintComponent

    Im writing a class called PolygonPanel. The class stores the users mouse clicks and redraws a polyline everytime the user clicks the mouse, then when the user presses the c key the polyline becomes a polygon and the coordinates of the polygon are stored in a text file

    The problem i am having is trying to get the save method to work in the paintComponent method. Any help would be appreciated and i can provide more of the class if needed.

    below is the paintComponent and the save method of the PolygonPanel

    public void paintComponent (Graphics page)
    		page.setColor (Color.red);
    		page.drawPolyline(x_coords, y_coords, numPoints);
            if (capture == true)// in other words when user presses c key
    			page.drawPolygon (x_coords, y_coords, numPoints);
    			save("SavedPolygons.rtf");//write the coordinates to this file
                //resests the coordinates for another polygon/polyline to be created
    			for (int i = 0; i<numPoints; i++)
    				x_coords[numPoints] = 0;
    				y_coords[numPoints] = 0;
    			numPoints = 0;
    	public void save(String file) throws IOException
    		PrintWriter out = new PrintWriter(new FileWriter(file));

  2. #2
    Member DanBrown's Avatar
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    Default Re: Throwing an Exception in paintComponent

    public void save(String file) throws IOException
    this method is throwing exception , but you are not catching the exception in the calling method.

    paintComponent is an overrided method , so its not possible to throw exception from paintComponent,
    so you need to handle it in save itself or in paintComponent .
    Thanks and Regards
    Dan Brown

    Common Java Mistakes

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