java - JButton does not change icon when pressed memory game -

i'm trying make own simple memory game , i'm having jpanel implements actionlistener interface , contains tiles inherits jbutton. works fine except fact button being clicked second, not change icon should do. when click 2 tiles match remain flipped , ok. when click 1st button flips on , second pressed tile provided not matching 1 behaves button without actionlistener added. thought fixing problem propertychangelistener can't figure out how.

this method in jpanel :

@override     public void actionperformed(actionevent e){          tile tile = (tile)e.getsource();          if(tilesflipped < 2 ){             tile.flip();             flippedtiles[tilesflipped++] = tile;              if(tilesflipped == 1){                 return;             }              if(flippedtiles[0].equals(flippedtiles[1])){                 tilesflipped = 0;                 return;              } else {                 try {                     thread.sleep(1000);                     for(int = 0; < 2; i++){                         flippedtiles[i].flipback();                     }                 } catch (interruptedexception e1) {                 }                }             tilesflipped = 0;         }       } 

and tile class :

private class tile extends jbutton {     string photopath;     imageicon photo;      tile(int i){         photopath = string.format("/home/stn/desktop/p/9-%d.jpg", i);         setpreferredsize(new dimension(150, 150));         this.setbackground(color.cyan);         this.photo = new imageicon(photopath);     }      public void flip(){         this.seticon(photo);         this.setbackground(color.white);     }      public void flipback(){         this.setbackground(color.cyan);         this.seticon(null);      }      public string getphotopath(){         return photopath;     }      @override     public boolean equals(object o){         return o instanceof tile && ((tile)o).getphotopath().equals(photopath);     }     @override     public int hashcode(){         return photopath.hashcode();     }  } 

use swing timer instead of thread.sleep(...). understand thread.sleep(...) puts current thread sleep, here swing event dispatch thread or edt, , put entire gui sleep, freezing application. swing timer 1 or repeated actions without tying edt. example:

 public void actionperformed(actionevent e) {      tile tile = (tile) e.getsource();      if (tilesflipped < 2) {        tile.flip();        flippedtiles[tilesflipped++] = tile;         if (tilesflipped == 1) {           return;        }         if (flippedtiles[0].equals(flippedtiles[1])) {           tilesflipped = 0;           return;         } else {           timer timer = new timer(1000, new actionlistener() {               @override              public void actionperformed(actionevent e) {                 (int = 0; < 2; i++) {                    flippedtiles[i].flipback();                 }                 tilesflipped = 0;              }           });           timer.setrepeats(false);           timer.start();        }     }   }