JavaFX: How to correctly color background of the selected TableCell?

Question

I want to change the row background color into green when to select a row. However, although the selected row was changed color, the additionally wrong row was also changed color. I can't figure out why??

This is a JavaFX program coding in Intellij of Windows 10.

TestFXML.java:

public class TestFXML implements Initializable {
    @FXML
    TableView<ItemLog> table;
    @FXML
    TableColumn<ItemLog,String> column1,column2,column4;
    @FXML
    TableColumn<ItemLog,Number> column3;

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        ObservableList<ItemLog> root=FXCollections.observableArrayList();
        root.addAll(
                new ItemLog("E0001","2.5㎟ XLPE", 1.2,"m"),
                new ItemLog("E0002","4㎟ XLPE",1.5,"m"),
                new ItemLog("E0003","6㎟ XLPE",2.0,"m"),
                new ItemLog("E0004","10㎟ XLPE",4.0,"m"),
                new ItemLog("E0005","16㎟ XLPE",6.2,"m"),
                new ItemLog("E0006","25㎟ XLPE",9.1,"m"),
                new ItemLog("E0007","35㎟ XLPE",14.5,"m"),
                new ItemLog("E0008","50㎟ XLPE",20.6,"m"),
                new ItemLog("E0009","70㎟ XLPE",31.2,"m"),
                new ItemLog("E00010","120㎟ XLPE",40.5,"m"),
                new ItemLog("E00011","150㎟ XLPE",55.3,"m"),
                new ItemLog("E00012","185㎟ XLPE",78.8,"m"),
                new ItemLog("E00013","240㎟ XLPE",96.0,"m"),
                new ItemLog("E0101","2.5㎟ PVC", 1.2,"m"),
                new ItemLog("E0102","4㎟ PVC",0.8,"m"),
                new ItemLog("E0103","6㎟ PVC",1.2,"m"),
                new ItemLog("E0104","10㎟ PVC",2.1,"m"),
                new ItemLog("E0105","16㎟ PVC",4.3,"m"),
                new ItemLog("E0106","25㎟ PVC",6.8,"m"),
                new ItemLog("E0107","35㎟ PVC",9.5,"m"),
                new ItemLog("E0108","50㎟ PVC",12.8,"m"),
                new ItemLog("E0109","70㎟ PVC",16.9,"m"),
                new ItemLog("E01010","120㎟ PVC",21.5,"m"),
                new ItemLog("E01011","150㎟ PVC",27.6,"m"),
                new ItemLog("E01012","185㎟ PVC",38.4,"m"),
                new ItemLog("E01013","240㎟ PVC",52.9,"m")
                );
        table.setItems(root);
        column1.setCellValueFactory(param -> param.getValue().code);
        column2.setCellValueFactory(param -> param.getValue().description);
        column3.setCellValueFactory(param -> param.getValue().price);
        column4.setCellValueFactory(param -> param.getValue().unit);
        //To change selected row color into green
        table.getFocusModel().focusedCellProperty().addListener((observable, oldValue, newValue) -> {
            if(newValue.getTableColumn() != null){
                newValue.getTableColumn().setCellFactory(param -> new TableCell(){
                    @Override
                    protected void updateItem(Object item, boolean empty) {
                        super.updateItem(item, empty);
                        if (empty) {
                            setText(null);
                            setGraphic(null);
                        }else{
                            setText(item.toString());
                            if(this.getIndex()==newValue.getRow()){
                                this.getTableRow().setStyle("-fx-background-color:green");
                            }
                        }
                    }
                });
            }
        });
    }
    private class ItemLog {
        StringProperty code=new SimpleStringProperty();
        StringProperty description=new SimpleStringProperty();
        DoubleProperty price=new SimpleDoubleProperty();
        StringProperty unit=new SimpleStringProperty();
        ItemLog(String code, String description, Double price, String unit) {
            this.code.set(code);
            this.description.set(description);
            this.price.set(price);
            this.unit.set(unit);
        }
    }
}

TestFXML.fxml:

<Pane prefHeight="414.0" prefWidth="602.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.TestFXML">
    <children>
       <TableView fx:id="table" maxHeight="1.7976931348623157E308" prefHeight="421.0" prefWidth="602.0">
         <columns>
           <TableColumn fx:id="column1" editable="false" prefWidth="100.0" text="A" />
           <TableColumn fx:id="column2" editable="false" prefWidth="300.0" text="B" />
             <TableColumn fx:id="column3" editable="false" prefWidth="100.0" text="C" />
             <TableColumn fx:id="column4" editable="false" prefWidth="100.0" text="D" />
        </columns>
      </TableView>
    </children>
</Pane>

I expected when I select 1st row, only 1st row changes in to green color. Actual result is when I selected 1st row, 1st and 19th rows changed in to green color.

Answer 1

There are 3 issues with your approach:

1. You never reset the look of the cell, if the cell becomes empty or the item is changed to a different one.
2. TableView usually does not recreate the cells, if the cellFactory changes. Each cellFactory chooses to highlight a cell based on the focused cell at the time the cellFactory creating the cell was created . Even if cells were recreated, you'd still see highlighted cells in other columns, since you never change back to a cellFactory not highlighting cells.
3. Focused and selected cells may differ.

Doing those modifications is much simpler, if you use a CSS stylesheet, since TableCell s get assigned a pseudo class when they get focused allowing you to only define the style of focused cells without the need to worry about cellFactory s:

style.css

.table-cell:selected {
    -fx-background-color: green;
}

fxml

<Pane stylesheets="style.css" prefHeight="414.0" prefWidth="602.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.TestFXML">
    ...
</Pane>

Remove the cellFactory assignments from your java code for the above approach to work.

To only style specific TableView s this way you could eg add a style class to the TableView and select it based on the style class of the TableView , eg

.my-tableview .table-cell:selected {
    -fx-background-color: green;
}

Also it becomes much simpler to combine different criteria, eg

/* style for selected and hovered cell */
.table-cell:selected:hover {
    -fx-background-color: yellow;
}

Answer 2

I got the solution by myself. To Modify that:

if(this.getIndex()==newValue.getRow()){
    this.getTableRow().setStyle("-fx-background-color:green");
}

into:

if(this.getIndex()==newValue.getRow()){
    this.getTableRow().setStyle("-fx-background-color:green");
}else{
    this.getTableRow().setStyle("");
}