Display animated gif in ImageIcon proxy with java swing -

i used write this

jlabel label=new jlable(url); frame.getcontentpane().add(label); 

and works animated gif image

however , when want use imageproxy load gif form internet doesn't work.

my imageproxy this

public class imageproxy implements icon{ imageicon imageicon; url imageurl; thread retrievalthread; boolean retrieving =false; public imageproxy(url url){     imageurl = url; }  public int geticonheight() {skip} public int geticonwidth() {skip}  @override public void painticon(final component c, graphics g, int x, int y) {     system.out.println("paint");     if(imageicon !=null){         imageicon.painticon(c, g, x, y);     }else{         g.drawstring("loading image", x+10, y+80);         if(!retrieving){             retrieving =true;             retrievalthread = new thread(new runnable(){                 public void run(){                     try{                         imageicon = new imageicon(imageurl);                         c.repaint();                     }catch(exception e){                         e.printstacktrace();                     }                 }             });             retrievalthread.start();         }     } } 

}

it can success load image won't auto refresh image have chage image zoom frame, every time zoom chage 1 picture

i read document , said , in other display gif need setimageobsever tried , doesn't work. , imageicon normal work no proxy print null getimageobserver

i tried read souce code did not understand.

pleas me ,thank you.

the source of problem in implementation of imageobserver interface jlabel:

public boolean imageupdate(image img, int infoflags,                int x, int y, int w, int h) {     // don't use getdisabledicon, trigger creation of icon if icon     // not set. if (!isshowing() ||         !swingutilities.doesiconreferenceimage(geticon(), img) &&         !swingutilities.doesiconreferenceimage(disabledicon, img)) {      return false; } return super.imageupdate(img, infoflags, x, y, w, h); } 

here code swingutilities.doesiconreferenceimage:

static boolean doesiconreferenceimage(icon icon, image image) { image iconimage = (icon != null && (icon instanceof imageicon)) ?                    ((imageicon)icon).getimage() : null; return (iconimage == image); } 

as can see, if icon not instance of imageicon result of imageupdate() false, without calling super's implementation responsible call repaint() on jlabel refresh new frame of animated icon. also, returning false means no longer interested in updates.

you may extend jlabel overcome constraint. here simple extension of jlabel overrides imageupdate(). actual code implementation of imageupdate taken component.imageupdate(), isinc , incrate constants simplicity:

public static class customlabel extends jlabel {     private static final boolean isinc = true;     private static final int incrate = 100;      public customlabel(icon image) {         super(image);     }      @override     public boolean imageupdate(image img, int infoflags, int x, int y,             int w, int h) {         int rate = -1;         if ((infoflags & (framebits | allbits)) != 0) {             rate = 0;         } else if ((infoflags & somebits) != 0) {             if (isinc) {                 rate = incrate;                 if (rate < 0) {                     rate = 0;                 }             }         }         if (rate >= 0) {             repaint(rate, 0, 0, getwidth(), getheight());         }         return (infoflags & (allbits | abort)) == 0;     } } 

you may plug imageupdate() add functionality of displaying "loading image" string while image still loading.

i wonder real reason behind implementation of proxy imageicon. if need synchronous image loading can use imageio api.