Javafx how to get cell from list(not value) - javafx

Question

I want get the cell(node,not data) from list by index.I need cast it to my custom cell and call its function.
I found a lot of question ask how to get value,but i find nothing about how to get cell itself.I try to use listView.getChildrenUnmodifiable().get(index),but it's not work.
The function i want to achieve is right clicking on the cell of list,then popup a context menu which have a 'rename' command,when i clicking the commond, startEdit function of cell need to be called.
How can i do that?

Answer 1

You should set the context menu on the individual cells, not on the list view itself. Here is a quick example:
Controller class with list view, and methods to invoke from context menu items:
import javafx.fxml.FXML;
import javafx.scene.control.ListView;
public class Controller {
#FXML
private ListView<String> listView ;
public void initialize() {
for (int i = 1 ; i <= 20 ; i++) {
listView.getItems().add("Item "+i);
}
listView.setCellFactory(lv -> new ListCellWithContextMenu(this));
}
public void edit(int index) {
listView.edit(index);
}
public void delete(int index) {
listView.getItems().remove(index);
}
}
The cell implementation:
import javafx.scene.control.ContextMenu;
import javafx.scene.control.MenuItem;
import javafx.scene.control.TextFormatter;
import javafx.scene.control.cell.TextFieldListCell;
public class ListCellWithContextMenu extends TextFieldListCell<String> {
private final ContextMenu contextMenu ;
public ListCellWithContextMenu(Controller controller) {
contextMenu = new ContextMenu();
MenuItem delete = new MenuItem("Delete");
MenuItem edit = new MenuItem("Edit");
contextMenu.getItems().addAll(edit, delete);
edit.setOnAction(e -> controller.edit(getIndex()));
delete.setOnAction(e -> controller.delete(getIndex()));
setConverter(TextFormatter.IDENTITY_STRING_CONVERTER);
}
#Override
public void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setContextMenu(null);
} else {
setContextMenu(contextMenu);
}
}
}
For completeness, an FXML file:
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.BorderPane?>
<?import javafx.scene.control.ListView?>
<BorderPane xmlns:fx="http://javafx.com/fxml/1" fx:controller="Controller">
<left>
<ListView fx:id="listView" editable="true" />
</left>
</BorderPane>
and an application class:
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class ListViewWithContextMenu extends Application {
#Override
public void start(Stage primaryStage) throws Exception {
Scene scene = new Scene(FXMLLoader.load(getClass().getResource("ListViewWithContextMenu.fxml")));
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}

Answer 2

James_D is right,you can register the context menus on the individual cells.
But in the situation which i have a lot of code relative to context menu,rewrite then all may cause other problems.After some try i use a another way.
For simplicity,I write two reusable class to implement the function that get cell by index from list directly.
If you think helpful,you can use the code below.
//let your cell extend this class
public class GetAbleListCell<T> extends ListCell<T>{
private ListViewHelper<T> libraryListHelper;
public GetAbleListCell(ListViewHelper<T> libraryListHelper) {
this.libraryListHelper = libraryListHelper;
}
#Override
public void updateIndex(int i) {
// TODO Auto-generated method stub
super.updateIndex(i);
if(getIndex()>0)
{
libraryListHelper.setCell(getIndex(),this);
}
}
}
//helper class
public class ListViewHelper<T> {
private ObservableList<GetAbleListCell<T>> list=FXCollections.observableArrayList();
public GetAbleListCell<T> getCell(int index) {
return list.get(index);
}
public void setCell(int index, GetAbleListCell<T> getAbleListCell) {
while(list.size()<index+1)
{
list.add(null);
}
list.set(index, getAbleListCell);
}
}
example
this.libraryListHelper=new ListViewHelper();
libraryLV.setCellFactory(param -> new LibraryCell(libraryListHelper));
.........
private void renameCurrentSelectedItems() {
//get cell directly
LibraryCell cell=(LibraryCell) libraryListHelper.getCell(libraryLV.getSelectionModel().getSelectedIndex());
cell.startEdit();
}
may contain some bug but it work in my situation