java - Has anyone succeeded in autocomplete ComboBox for list cell? -

as standalone element, this solution works fine.

but in custom listcell (mirrored comboboxlistcell sources), gives sometimes:

exception in thread "javafx application thread" java.lang.nullpointerexception @ com.sun.javafx.scene.control.skin.comboboxpopupcontrol.positionandshowpopup(comboboxpopupcontrol.java:100) @ com.sun.javafx.scene.control.skin.comboboxpopupcontrol.show(comboboxpopupcontrol.java:74) @ com.sun.javafx.scene.control.skin.comboboxbaseskin.handlecontrolpropertychanged(comboboxbaseskin.java:115) @ com.sun.javafx.scene.control.skin.comboboxlistviewskin.handlecontrolpropertychanged(comboboxlistviewskin.java:245) @ com.sun.javafx.scene.control.skin.behaviorskinbase$2.call(behaviorskinbase.java:189) @ com.sun.javafx.scene.control.skin.behaviorskinbase$2.call(behaviorskinbase.java:187) @ com.sun.javafx.scene.control.multiplepropertychangelistenerhandler$1.changed(multiplepropertychangelistenerhandler.java:55) @ javafx.beans.value.weakchangelistener.changed(weakchangelistener.java:89) @ com.sun.javafx.binding.expressionhelper$singlechange.firevaluechangedevent(expressionhelper.java:176) @ com.sun.javafx.binding.expressionhelper.firevaluechangedevent(expressionhelper.java:80) @ javafx.beans.property.readonlybooleanwrapper$readonlypropertyimpl.firevaluechangedevent(readonlybooleanwrapper.java:178) @ javafx.beans.property.readonlybooleanwrapper$readonlypropertyimpl.access$100(readonlybooleanwrapper.java:148) @ javafx.beans.property.readonlybooleanwrapper.firevaluechangedevent(readonlybooleanwrapper.java:144) @ javafx.beans.property.booleanpropertybase.markinvalid(booleanpropertybase.java:110) @ javafx.beans.property.booleanpropertybase.set(booleanpropertybase.java:143) @ javafx.scene.control.comboboxbase.setshowing(comboboxbase.java:202) @ javafx.scene.control.comboboxbase.show(comboboxbase.java:407) 

seems show() method combobox can produce npe inside javafx code.

custom comboboxlistcell differs in startedit():

@override public void startedit() {     if (! iseditable() || ! getlistview().iseditable()) {         return;     }      if (combobox == null) {         combobox = createcombobox(this, items, converterproperty());          //the special string         handler = new autocompletecomboboxlistener<>(combobox);          combobox.editableproperty().bind(comboboxeditableproperty());      }      combobox.getselectionmodel().select(getitem());      super.startedit();      if (isediting()) {         settext(null);         setgraphic(combobox);     } } 

code of autocompletecomboboxlistener gives npe:

@override public void handle(keyevent event) {      if(event.getcode() == keycode.up) {         caretpos = -1;         movecaret(combobox.geteditor().gettext().length());         return;     } else if(event.getcode() == keycode.down) {         if(!combobox.isshowing()) {             combobox.show();         }         caretpos = -1;         movecaret(combobox.geteditor().gettext().length());         return;     } else if(event.getcode() == keycode.back_space) {         movecarettopos = true;         caretpos = combobox.geteditor().getcaretposition();     } else if(event.getcode() == keycode.delete) {         movecarettopos = true;         caretpos = combobox.geteditor().getcaretposition();     }      if (event.getcode() == keycode.right || event.getcode() == keycode.left             || event.iscontroldown() || event.getcode() == keycode.home             || event.getcode() == keycode.end || event.getcode() == keycode.tab) {         return;     }      observablelist list = fxcollections.observablearraylist();     (int i=0; i<data.size(); i++) {         if(data.get(i).tostring().tolowercase().startswith(             autocompletecomboboxlistener.this.combobox             .geteditor().gettext().tolowercase())) {             list.add(data.get(i));         }     }     string t = combobox.geteditor().gettext();      combobox.setitems(list);     combobox.geteditor().settext(t);     if(!movecarettopos) {         caretpos = -1;     }     movecaret(t.length());     if(!list.isempty()) {          //this gives npe inside javafx api         combobox.show();     } } 

ok, problem setitems skips current selection -1, , listcell treat fact if new value (null) needs committed (if current selection != -1). , after commit there nothing show combobox cause it's in non editing state.

so it's design issue, not bug. comboboxlistcell code not able change items on-the-fly without special care.