java - SWT Resize Error -

i've been using swt , have found issue.

when selecting , deselecting check boxes , maximizing window cause icon of first button set though null. layout of text on buttons can end incorrect.

to recreate error:

1. select checkbox 1
2. deselect checkbox 1
3. select checkbox 3
4. maximize window

the icon checkbox 1 should null (empty) instead has cross icon.

  public static void main(string[] args) {        final display d = new display();        shell s = new shell(d);        s.setlayout(new gridlayout(2, false));        s.setsize(500, 500);         new label(s, swt.none).settext("c");        final button c = new button(s, swt.check);         new label(s, swt.none).settext("l1");        final button b = new button(s, swt.push | swt.flat);        b.setlayoutdata(new griddata(swt.fill, swt.center, true, false));        b.settext("button 1");        b.setenabled(false);         new label(s, swt.none).settext("c2");        final button c2 = new button(s, swt.check);         new label(s, swt.none).settext("l2");        final button b2 = new button(s, swt.push | swt.flat);        b2.setlayoutdata(new griddata(swt.fill, swt.center, true, false));        b2.setimage(null);        b2.settext("button 2");        b2.setenabled(false);         new label(s, swt.none).settext("c3");        final button c3 = new button(s, swt.check);         new label(s, swt.none).settext("l3");        final button b3 = new button(s, swt.push | swt.flat);        b3.setlayoutdata(new griddata(swt.fill, swt.center, true, false));        b3.settext("button 3");        b3.setenabled(false);         c.addselectionlistener(new selectionadapter() {            @override            public void widgetselected(selectionevent e) {                if (!b.isenabled()) {                    b.setimage(d.getsystemimage(swt.icon_error));                    b.setenabled(true);                } else {                    b.setimage(null);                    b.setenabled(false);                }            }        });         c2.addselectionlistener(new selectionadapter() {            @override            public void widgetselected(selectionevent e) {                if (!b2.isenabled()) {                    b2.setimage(d.getsystemimage(swt.icon_error));                    b2.setenabled(true);                } else {                    b2.setimage(null);                    b2.setenabled(false);                }            }        });         c3.addselectionlistener(new selectionadapter() {            @override            public void widgetselected(selectionevent e) {                if (!b3.isenabled()) {                    b3.setimage(d.getsystemimage(swt.icon_error));                    b3.setenabled(true);                } else {                    b3.setimage(null);                    b3.setenabled(false);                }            }        });         s.open();        while (!s.isdisposed()) {            if (!d.readanddispatch())                d.sleep();        }        d.dispose();    } 

this isn't ideal means, if need workaround, 1 thing try wrapping button , using stacklayout flip between enabled button , disabled button. way you're not adding/removing image. fixes layout issues because actual button instances not changing state.

for example:

public static class mybutton {      private final button buttonenabled;     private final button buttondisabled;      private final composite stackcomposite;     private final stacklayout stacklayout;      public mybutton(final composite parent, final string text) {         stackcomposite = new composite(parent, swt.none);         stacklayout = new stacklayout();         stackcomposite.setlayout(stacklayout);         stackcomposite.setlayoutdata(new griddata(swt.fill, swt.fill, true, false));          buttonenabled = createbutton(stackcomposite, text, true);         buttondisabled = createbutton(stackcomposite, text, false);          stacklayout.topcontrol = buttonenabled;     }      public void setenabled(final boolean enabled) {         stacklayout.topcontrol = enabled ? buttonenabled : buttondisabled;         stackcomposite.layout();     }      public boolean isenabled() {         return stacklayout.topcontrol.equals(buttonenabled) ? true : false;     }      private static button createbutton(final composite parent,             final string text, final boolean enabled) {         final button button = new button(parent, swt.push | swt.flat);         button.setlayoutdata(new griddata(swt.fill, swt.center, true, false));         button.settext(text);         button.setenabled(enabled);         if (enabled) {             button.setimage(parent.getdisplay().getsystemimage(swt.icon_error));         }         return button;     }  } 

again, isn't ideal, can add methods (addlistener(...), etc.) mybutton class call methods on enabled button, implementation detail.

changes main method:

public static void main(final string[] args) {      // ...      new label(s, swt.none).settext("c");     final button c = new button(s, swt.check);      new label(s, swt.none).settext("l1");     final mybutton b = new mybutton(s, "button 1");      // ...      c.addselectionlistener(new selectionadapter() {         @override         public void widgetselected(final selectionevent e) {             b.setenabled(!b.isenabled());         }     });      // ...  } 

result: (note changed first button)