Cell factory in javafx

Question

I am using JavaFx 2.0 and Java 7. The question is regarding Table View in JavaFX.

The below sample code creates a firstName column and assigns cell factory and cell value factory to it.

Callback<TableColumn, TableCell> cellFactory = 
new Callback<TableColumn, TableCell>() {
    public TableCell call(TableColumn p) {
        return new EditingCell();
} };


TableColumn firstNameCol = new TableColumn("First Name");
    firstNameCol.setCellValueFactory(
        new PropertyValueFactory<Person,String>("firstName")
    );
firstNameCol.setCellFactory(cellFactory);

My requirement is I have a column which doesn't directly map to a single attribute in Person object, but instead is a custom value created by concatenating one or more attributes of Person object.

Consider a scenario where I have a table column named Full Name which will have values of Prefix + Last Name + "," + First Name .

1) In this scenario, how will you write the cell value factory?

firstNameCol.setCellValueFactory(
            new PropertyValueFactory<Person,String>(???????)
        );

2) how will you write cell factory?

In this scenario do we need to implement both cell value factory and cell factory or any one is sufficient? If one is sufficient then which one?

Thanks

score 31 · Answer 1 · answered May 10 '12 at 10:26

Straightforwardly,

Cell Value Factory : it is like a "toString()" of only part of the row item for that related cell.
Cell Factory : it is a renderer of the cell from the cell item. Default behavior is setText(cell.item.toString()) if the cell item is not a Node, setGraphic((Node)cell.item) otherwise. Set this property if the cell is supposed to support editing OR if you want more graphics (controls) other than default Label.

So for your scenario, leaving cell factory with default value will be sufficient (2). And here is sample code for (1):

firstAndLastNameCol.setCellValueFactory(new Callback<TableColumn.CellDataFeatures<Person, String>, ObservableValue<String>>() {

    @Override
    public ObservableValue<String> call(TableColumn.CellDataFeatures<Person, String> p) {
        if (p.getValue() != null) {
            return new SimpleStringProperty(p.getValue().getPrefix() + " " + p.getValue().getFirstName() + "," + p.getValue().getLastName());
        } else {
            return new SimpleStringProperty("<no name>");
        }
    }
});

Thank you man, I have spent three hours looking for the anwser. Finally got it here. You are the boss :) — Martin, Apr 24 '17 at 12:02

score 8 · Answer 2 · answered Aug 08 '12 at 12:17

8

You can also just modify the getter method of your data object. In your case this is the class Person, which holds firstName, lastName and (presumably) prefix.

Add a new method to the Person class:

public String getTotalName() {
  return this.prefix + " " + this.getLastName() + ", " + this.getFirstName();
}

and then just apply the CellValueFactory:

totalNameCol.setCellValueFactory(
  new PropertyValueFactory<Person,String>("totalName")
);

I find this more comfortable and than using callbacks.

answered Aug 08 '12 at 12:17

Peter Ilfrich

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I don't like this approach. It´s so obvious what will happen if someone renames the variable `totalName`. The code won't work anymore and the compiler can't tell you that. – Kai Aug 29 '15 at 08:04
@Kai why they will change variable name? If you change variable name then any approach will be affected. – Asif Mushtaq Aug 06 '16 at 11:52
1

@UnKnown One could think `fullName` is more descriptive than `totalName`. That's a legit reason to refactor that name. It's not a good practice to rely on variable names. Think about the fear you feel when refactoring such code... But if you write a good unit tests which tests that binding you might get away with it. Uluk's answer shows how to do it without that binding. – Kai Aug 06 '16 at 19:16

Cell factory in javafx

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