Question

I made an Applet with some Panels on it.
I draw something on a panel with specific methods I created, they use a graphics object to draw.
To draw I use commands like:

gr = this.getGraphics;  
gr.drawString... etc  

Then I call these methods from the applet class.
My problem is the following: After I minimize or resize the browser window the panel does not
show anything, I suppose it’s because I didn’t implement anything in the paint() method of the panel.
Is there an way to fix that problem without changing all my methods?

Some of my methods are like that:

//paint a node with coords x,y and nodeNumber in the center of the node
public void paintNode(int x,int y,Integer numberOfNode){

    gr = this.getGraphics();
    gr.setColor(ShowGUI.getPanelColor());
    gr.fillOval(x,y,40,40);
    gr.setColor(Color.BLACK);
    gr.drawOval(x,y,40,40);
    gr.drawString(numberOfNode.toString(),x+17,y+25);

}

//marks red the processing edge
public void markEdge(int x1,int y1,int x2,int y2,Integer numberOfNode1,Integer numberOfNode2,int weight){

    gr.setColor(Color.red);
    this.paintEdge(x1,y1,x2,y2,numberOfNode1,numberOfNode2,weight);
    this.paintNode(x1, y1, numberOfNode1);
    this.paintNode(x2, y2, numberOfNode2);

}

Answer 1

You need to call update()/repaint() methods on Panel when window is minimized and maximized.

You will need to override start() method of applet and add repaint() to it.
Defination for start():

public void start():
This is called after the “init” event. It is also called at times when the user is not using your applet and starts to use it again such as when a minimized browser containning your applet is maximized.

Here is how you code should look:

public void start(){
    super.start();
    this.repaint();
}

Hope this helps.