java - Message dialog reappears over and over -

we made method determine our image in our frame. if image in part of frame show message dialog , return our main jpanel ( we're making minigolf game ;) )

the problem when message dialog appears, keeps reappearing after switched our main panel. here's code:

    package project; import java.awt.graphics; import java.awt.image; import java.io.file; import javax.swing.imageicon; import javax.swing.jlabel; import javax.swing.joptionpane;  public class blackhole  { image blackhole; int xblack; int yblack; public final int breedte=75; public final int hoogte=75; public string afbeelding2; public atoom atoom; public frame venster; public spelpaneel x;  public blackhole(int xblack, int yblack, string afbeelding2) {     this.xblack = xblack;     this.yblack = yblack;     blackhole = new imageicon(getclass().getresource(afbeelding2)).getimage(); }  public void tekenblackhole(graphics g) {     g.drawimage(blackhole,xblack,yblack,75,75,null); }  public boolean gameover(atoom atoom)  {     return ((atoom.xpositie +atoom.breedte > this.xblack) && (atoom.xpositie < this.xblack + this.breedte) && (atoom.ypositie + atoom.hoogte>this.yblack && atoom.ypositie<this.yblack+this.hoogte )) ;    } 

and method call upon in our class playing happens.

    if (blackhole.gameover(atoom))     {          joptionpane.showmessagedialog(null, "you're goneee in black hole !!");         venster.switchpanel();     } 

you need have boolean variable tell if message has been shown. like

if (blackhole.gameover(atoom) && !messagehasbeenshown) {         messagehasbeenshown = true;         joptionpane.showmessagedialog(null, "you're goneee in black hole !!");         venster.switchpanel(); } 

and messagehasbeenshown = true; somewhere before.