javafx - Drag and drop item into TableView, between existing rows -

table contains following rows (one column example):

a b c 

i'm trying figure out how drag item it, , have placed between existing rows b , c.

i able drag-and-drop results in item added @ end of table can't figure out how place in between rows, based on release mouse button.

create rowfactory producing tablerows accept gesture , decide mouse position, whether add item before or after row:

@override public void start(stage primarystage) {     tableview<item> table = new tableview<>();      button button = new button("a");      // d&d source providing next char     button.setondragdetected(evt -> {         dragboard db = button.startdraganddrop(transfermode.move);         clipboardcontent content = new clipboardcontent();         content.putstring(button.gettext());         db.setcontent(content);     });     button.setondragdone(evt -> {         if (evt.isaccepted()) {             // next char             button.settext(character.tostring((char) (button.gettext().charat(0) + 1)));         }     });      // accept empty table     table.setondragover(evt -> {         if (evt.getdragboard().hasstring()) {             evt.accepttransfermodes(transfermode.copy_or_move);         }         evt.consume();     });     table.setondragdropped(evt -> {         dragboard db = evt.getdragboard();         if (db.hasstring()) {             table.getitems().add(new item(db.getstring()));             evt.setdropcompleted(true);         }         evt.consume();     });      tablecolumn<item, string> col = new tablecolumn<>("value");     col.setcellvaluefactory(new propertyvaluefactory<>("value"));     table.getcolumns().add(col);      // let rows accept drop     table.setrowfactory(tv -> {         tablerow<item> row = new tablerow();         row.setondragover(evt -> {             if (evt.getdragboard().hasstring()) {                 evt.accepttransfermodes(transfermode.copy_or_move);             }             evt.consume();         });         row.setondragdropped(evt -> {             dragboard db = evt.getdragboard();             if (db.hasstring()) {                 item item = new item(db.getstring());                 if (row.isempty()) {                     // row empty (at end -> append item)                     table.getitems().add(item);                 } else {                     // decide based on drop position whether add element before or after                     int offset = evt.gety() > row.getheight() / 2 ? 1 : 0;                     table.getitems().add(row.getindex() + offset, item);                     evt.setdropcompleted(true);                 }             }             evt.consume();         });         return row;     });      scene scene = new scene(new vbox(button, table));      primarystage.setscene(scene);     primarystage.show(); } 

public class item {      public item() {     }      public item(string value) {         this.value.set(value);     }      private final stringproperty value = new simplestringproperty();      public string getvalue() {         return value.get();     }      public void setvalue(string val) {         value.set(val);     }      public stringproperty valueproperty() {         return value;     }  }