TableColumn, How to connect it with property but not fill the cells - tableview

Question

I have a TableView and Data class with integer properties for columns. However I would like columns at first show empty cells so user can put value he wants.
Right now its impossible because when creating Data object, integer values has to be created with initial value, so table shows up filled already with numbers.
private ObservableList<MyData> dataList = FXCollections.observableArrayList();
.....edited....
private void buttAddColumnAction(ActionEvent event){
int i = numberOfColumns;// thats the key for lambda expression. Unicate number for column to access its variable;
if(dataList.size() > 0)//resizing each data object with new variable
for(MyData x: dataList)
x.addNew();
TableColumn<MyData, Integer> newColumn = new TableColumn<>("#" + String.valueOf(++numberOfColumns));
newColumn.setCellValueFactory(cellData -> cellData.getValue().getCellValue(i));
// newColumn.setCellFactory(TextFieldTableCell.<MyData, Integer>forTableColumn(new IntegerStringConverter()));
Callback<TableColumn<MyData, Integer>, TableCell<MyData, Integer>> cellFactoryInt = (TableColumn<MyData, Integer> p) -> new EditingCellNumbers(tableView);
newColumn.setCellFactory(cellFactoryInt);
tableView.getColumns().add(newColumn);
}
public class MyData{ //dont forget about public because you wont get acces to properties
private ObservableList<ObjectProperty<Integer>> cellValue = FXCollections.observableArrayList();
public MyData(int howManyColumns) {
for(int i=0; i<howManyColumns; ++i)
this.cellValue.add(new SimpleObjectProperty<Integer>(null));
}
public ObjectProperty<Integer> getCellValue(int whichOne) {
return cellValue.get(whichOne);
}
public void setCellValue(int cellValue, int whichOne) {
this.cellValue.set(whichOne, new SimpleObjectProperty<Integer>(cellValue));
}
public void addNew(){ //ads another variable for another column
cellValue.add(new SimpleObjectProperty<Integer>(null));
}
public void deleteLast(){ //deletes last variable when column is deleted
cellValue.remove(cellValue.size()-1);
}
}
CellFactory
//Klasa ta pozwala na definiowania zachowania komórek, które edytuje użytkownik
public class EditingCellNumbers extends TableCell<MyData, Integer>{
private TextField textField;
private TableView<MyData> parentTableView;
public static int numberOfColumns;
public EditingCellNumbers(TableView<MyData> parent) {
this.parentTableView = parent;
numberOfColumns = parent.getColumns().size();
}
#Override
public void startEdit(){
if (!isEmpty()) {
super.startEdit();
createTextField();
setText(null);
setGraphic(textField);
textField.selectAll();
textField.requestFocus();
}
}
#Override
public void cancelEdit() {
super.cancelEdit();
setText(String.valueOf(getItem()));
setGraphic(null);
}
#Override
public void updateItem(Integer item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setText(null);
setGraphic(null);
} else {
if (isEditing()) {
if (textField != null) {
textField.setText(getString());
}
setText(null);
setGraphic(textField);
} else {
setText(getString());
setGraphic(null);
}
}
}
private void createTextField() {
textField = new TextField(getString());
textField.setMinWidth(this.getWidth() - this.getGraphicTextGap()* 2);
textField.focusedProperty().addListener(
(ObservableValue<? extends Boolean> arg0,
Boolean arg1, Boolean arg2) -> {
if (!arg2) {
XXX commitEdit(Integer.valueOf(textField.getText()));
}
});
textField.setOnKeyReleased(new EventHandler<Event>() {
#Override
public void handle(Event event) {
try{
int i = Integer.valueOf(textField.getText());
//digit given...
if( (i>=0) && (i<10) ){//making sure cell is filled with just one digit
commitEdit(Integer.valueOf(textField.getText()));
int selectedColumn = parentTableView.getSelectionModel().getSelectedCells().get(0).getColumn(); // gets the number of selected column
int selectedRow = parentTableView.getSelectionModel().getSelectedCells().get(0).getRow();
if(selectedColumn < numberOfColumns-1){
parentTableView.getSelectionModel().selectNext();
parentTableView.edit(selectedRow, parentTableView.getColumns().get(selectedColumn+1));
}else{
parentTableView.getSelectionModel().select(selectedRow+1, parentTableView.getColumns().get(0));
parentTableView.edit(selectedRow+1, parentTableView.getColumns().get(0));
}
}else
textField.clear();
}catch(NumberFormatException e){
textField.clear();
}
}
});
}
private String getString() {
return getItem() == null ? "" : getItem().toString();
}
}

Answer 1

Allow null values in your column by using an ObjectProperty<Integer> instead of an IntegerProperty. This gives a more natural way to define "not initialized" than representing it with 0 (or some other proxy value).
Then you can use the TextFieldTableCell, but just supply a custom StringConverter<Integer>:
public class MyData{ //dont forget about public because you wont get acces to properties
private ObservableList<ObjectProperty<Integer>> cellValue = FXCollections.observableArrayList();
public MyData(int howManyColumns) {
for(int i=0; i<howManyColumns; ++i)
this.cellValue.add(new SimpleObjectProperty<>(new Random().nextInt(10)));
}
// ...
}
and
newColumn.setCellValueFactory(cellData -> cellData.getValue().getCellValue(i));
newColumn.setCellFactory(TextFieldTableCell.<MyData, Integer>forTableColumn(new StringConverter<Integer>() {
#Override
public String toString(Integer i) {
if (i == null) {
return "" ;
} else {
return i.toString();
}
}
#Override
public Integer fromString(String string) {
if (string.trim().length() == 0) {
return null ;
} else {
try {
return Integer.valueOf(string);
} catch (NumberFormatException nfe) {
return null ;
}
}
}
}));
Complete example:
import java.util.Random;
import java.util.function.Function;
import javafx.application.Application;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.beans.value.ObservableValue;
import javafx.scene.Scene;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.TextFieldTableCell;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
import javafx.util.StringConverter;
public class TableViewWithEmptyIntegerColumn extends Application {
#Override
public void start(Stage primaryStage) {
TableView<Item> table = new TableView<>();
table.setEditable(true);
TableColumn<Item, String> nameCol = createCol("Name", Item::nameProperty);
TableColumn<Item, Integer> valueCol = createCol("Value", Item::valueProperty);
valueCol.setEditable(true);
valueCol.setCellFactory(TextFieldTableCell.forTableColumn(new StringConverter<Integer>() {
#Override
public String toString(Integer i) {
if (i == null) {
return "" ;
} else {
return i.toString() ;
}
}
#Override
public Integer fromString(String string) {
if (string.trim().length() == 0) {
return null ;
} else {
// better to check for a valid int format instead of using try-catch...
try {
return Integer.valueOf(string);
} catch (NumberFormatException nfe) {
return null ;
}
}
}
}));
Random rng = new Random();
for (int i=1; i<=20; i++) {
if (rng.nextDouble() < 0.5) {
table.getItems().add(new Item("Item "+i));
} else {
table.getItems().add(new Item("Item "+i, rng.nextInt(10)+1));
}
}
table.getColumns().addAll(nameCol, valueCol);
primaryStage.setScene(new Scene(new BorderPane(table), 400, 600));
primaryStage.show();
}
private <S,T> TableColumn<S,T> createCol(String title, Function<S, ObservableValue<T>> property) {
TableColumn<S,T> col = new TableColumn<>(title);
col.setCellValueFactory(cellData -> property.apply(cellData.getValue()));
return col ;
}
public static class Item {
private final StringProperty name = new SimpleStringProperty();
private final ObjectProperty<Integer> value = new SimpleObjectProperty<>();
public Item(String name, Integer value) {
setName(name);
setValue(value);
}
public Item(String name) {
this(name, null);
}
public final StringProperty nameProperty() {
return this.name;
}
public final String getName() {
return this.nameProperty().get();
}
public final void setName(final String name) {
this.nameProperty().set(name);
}
public final ObjectProperty<Integer> valueProperty() {
return this.value;
}
public final Integer getValue() {
return this.valueProperty().get();
}
public final void setValue(final Integer value) {
this.valueProperty().set(value);
}
}
public static void main(String[] args) {
launch(args);
}
}