I have a ComboBox populated with a custom object. However, I need to allow the selection of no selection (or a null value). I have tried comboBox.getItems().add(null) but that does not add an empty selection.
How do I add a blank selection at the top to essentially allow a user to "deselect" all items?
You could add a placeholder element. Instead of checking for deselected items you simply need to test reference equality. Depending on the class design you may need to use a custom cell factory to display the no text for this item:
public class CustomItem {
private final String text;
public CustomItem(String text) {
this.text = text;
}
public String getText() {
return text;
}
}
final CustomItem emptyPlaceholder = new CustomItem(null);
ComboBox<CustomItem> combo = new ComboBox<>();
combo.getItems().addAll(emptyPlaceholder, new CustomItem("foo"), new CustomItem("bar"));
combo.setCellFactory(lv -> new ListCell<CustomItem>() {
#Override
protected void updateItem(CustomItem item, boolean empty) {
super.updateItem(item, empty);
setText((empty || item == null || item == emptyPlaceholder)
? ""
: item.getText());
}
});
combo.setButtonCell(combo.getCellFactory().call(null));
Related
I have customized a Hyperlink cell here. I want the tableview to select the content when I click this link, but after I add Hyperlink, the tableview's selected seems to be invalid.
tb_uGoodUrl.setCellFactory(new Callback<TableColumn<GoodModel, String>, TableCell<GoodModel, String>>() {
#Override
public TableCell<GoodModel, String> call(TableColumn<GoodModel, String> param) {
TableCell<GoodModel, String> cell = new TableCell<GoodModel, String>() {
private final Hyperlink hyperlink = new Hyperlink();
{
hyperlink.setOnMouseClicked(event -> {
if(event.getClickCount() == 2){
String url = getItem();
hostServices.showDocument(url);
}
});
}
#Override
protected void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setGraphic(null);
}else {
hyperlink.setText(getItem());
setGraphic(hyperlink);
}
}
};
return cell;
}
});
Click on the link, the cell is not selected
If the cell is not selected, a null exception will be reported when the following code is used.
TablePosition pos = tableView.getSelectionModel().getSelectedCells().get(0);
int row = pos.getRow();
// Item here is the table view type:
GoodModel item = tableView.getItems().get(row);
TableColumn col = pos.getTableColumn();
// this gives the value in the selected cell:
String data = (String) col.getCellObservableValue(item).getValue();
The effect you want to achieve is as follows
Rendering
You can manually select the cell, using the table's selection model, when the Hyperlink is clicked on.
// Assuming this code is inside a TableCell implementation
hyperlink.setOnAction(event -> {
event.consume();
getTableView().getSelectionModel().select(getIndex(), getTableColumn());
// show your document
});
I used the onAction property which will be fired when the Hyperlink has been clicked once. This is typical behavior for a hyperlink, but if you want to only perform the action on a double-click then you can keep using your onMouseClicked handler.
Note the above does not take into account multiple-selection mode.
How can I change the appearance of a cell based on the status of another cell in the same column of a tableView in JavaFX.
colHidden.setCellValueFactory(param -> {
return param.getValue().hiddenProperty();
});
colHidden.setCellFactory(tc -> new CheckBoxTableCell<>());
colLabel.setCellFactory(...);
I have a cell which contains CheckBoxTableCell<>(). When I select this checkbox the content of the cell colLabel should be replaced by asterisks.
You can do something like this. The basic idea here is to "remember" the property corresponding to the check box in the same row, assuming the cell is not empty, and add a listener to it that updates the text. Then remove the listener from the previous property whenever the cell updates.
colLabel.setCellFactory(col -> new TableCell<RowType, ColumnType>() {
private ObservableValue<Boolean> hiddenProperty ;
ChangeListener<Boolean> listener = (obs, wasHidden, isNowHidden) -> updateText(isNowHidden);
#Override
protected void updateItem(ColumnType item, boolean empty) {
super.updateItem(item, empty);
if (hiddenProperty != null) {
hiddenProperty.removeListener(listener);
}
if (empty) {
setText(null);
hiddenProperty = null ;
} else {
hiddenProperty = getTableView().getItems().get(getIndex()).hiddenProperty();
hiddenProperty.addListener(listener);
updateText(hiddenProperty.get());
}
}
private void updateText(boolean hidden) {
if (hidden) {
setText("********");
} else {
setText(getItem().toString()); // or other format for string, etc
}
}
}
Replace RowType and ColumnType with the actual types used by colLabel (i.e. this assumes you have TableColumn<RowType, ColumnType> colLabel ;).
I've created a simple TableView that is fed with data from a database, and what I want is just to be able to easily change the value of a numeric column of that table with JavaFx.
But... since I have some mental issue or something, I can't make it work.
Below it's the "SpinnerCell" component, and the issue I've been having is that even after the commitEdit is fired, when I get the items from the TableView, no values were altered. What am I missing from this update lifecycle?
import javafx.scene.control.Spinner;
import javafx.scene.control.TableCell;
public class SpinnerTableCell<S, T extends Number> extends TableCell<S, T> {
private final Spinner<T> spinner;
public SpinnerTableCell() {
this(1);
}
public SpinnerTableCell(int step) {
this.spinner = new Spinner<>(0, 100, step);
this.spinner.valueProperty().addListener((observable, oldValue, newValue) -> commitEdit(newValue));
}
#Override
protected void updateItem(T c, boolean empty) {
super.updateItem(c, empty);
if (empty || c == null) {
setText(null);
setGraphic(null);
return;
}
this.spinner.getValueFactory().setValue(c);
setGraphic(spinner);
}
}
Because your table cell is always showing the editing control (the Spinner), you bypass the usual table cell mechanism for beginning an edit. For example, in the TextFieldTableCell, if the cell is not in an editing state, then a label is shown. When the user double-clicks the cell, it enters an editing state: the cell's editingProperty() is set to true, and the enclosing TableView's editingCellProperty() is set to the position of the current cell, etc.
In your case, since this never happens, isEditing() is always false for the cell, and as a consequence, commitEdit() becomes a no-op.
Note that the CheckBoxTableCell is implemented similarly: its documentation highlights this fact. (The check box table cell implements its own direct update of properties via the selectedStateCallback.)
So there are two options here: one would be to enter an editing state when the spinner gains focus. You can do this by adding the following to the cell's constructor:
this.spinner.focusedProperty().addListener((obs, wasFocused, isNowFocused) -> {
if (isNowFocused) {
getTableView().edit(getIndex(), getTableColumn());
}
});
Another option would be to provide a callback for "direct updates". So you could do something like:
public SpinnerTableCell(BiConsumer<S,T> update, int step) {
this.spinner = new Spinner<>(0, 100, step);
this.spinner.valueProperty().addListener((observable, oldValue, newValue) ->
update.accept(getTableView().getItems().get(getIndex()), newValue));
}
and then given a model class for the table, say
public class Item {
private int value ;
public int getValue() { return value ;}
public void setValue(int value) { this.value = value ;}
// ...
}
You could do
TableView<Item> table = ... ;
TableColumn<Item, Integer> valueCol = new TableColumn<>("Value");
valueCol.setCellValueFactory(cellData -> new SimpleIntegerProperty(cellData.getValue().getValue()).asObject());
valueCol.setCellFactory(tc -> new SpinnerTableCell<>(Item::setValue, 1));
I want to be able to color individual Tree Item of treeView based on some condition.
This answer seems good but I am unable to implement it.
https://stackoverflow.com/a/10931896/6653207
I am unable to understand how to use setCellFactory method to format individual TreeItems.
I have a class
public class Bag {
public String caption,assignment="";
Boolean eval;
public Set<Vertex> Nodes = new HashSet<Vertex>();
public Vector<Bag> ChildBags = new Vector<Bag>();
#Override
public String toString()
{
return assignment+ " " +caption;
}
}
Here's my css file:
.true{
-fx-text-fill:#33cc00 ;
}
.assignment{
-fx-text-fill: #0033cc
}
So I want to color to green the caption ( the toString() method returns ) of all those nodes whose eval property is true.
and assignment string which toString() method returns for all the nodes should be blue.
How can I do so?
Thanks.
By overriding the updateItem method of the TreeCell, you can adjust the TreeCell's properties based on the value of the TreeItem the cell contains.
In the following example a pseudoclass is assigned to all cells that contain a value with the prefix "child" and all empty cells get a black background.
TreeView<String> treeView = ...
PseudoClass childPseudoClass = PseudoClass.getPseudoClass("child");
treeView.setCellFactory(tv -> new TreeCell<String>() {
#Override
protected void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
if (empty || item == null) {
// update for empty cell / cell containing null
pseudoClassStateChanged(childPseudoClass, false);
setText("");
setStyle("-fx-background-color: black;");
} else {
// update for filled cell
pseudoClassStateChanged(childPseudoClass, item.startsWith("child"));
setText(item);
setStyle(null);
}
}
});
CSS Stylesheet
.tree-cell:child {
-fx-background-color: red;
}
The updateItem method is called by the TreeView every time the value changes, e.g. if a new TreeItem is associated with the cell or the value property of a TreeItem is modified.
You could also use the factory to add listeners to the TreeCell, before it's returned, in case you prefer this and e.g. want to change the cell based on the treeItem property.
EDIT: To apply different colors to the text, you need to use different Nodes for the text parts.
treeView.setCellFactory(tv -> new TreeCell<Bag>() {
private final Text assignment;
private final Text caption;
private final Node graphic;
{
assignment = new Text();
caption = new Text();
assignment.getStyleClass().add("assignment");
graphic = new HBox(4, assignment, caption);
setGraphic(graphic);
}
#Override
protected void updateItem(Bag item, boolean empty) {
super.updateItem(item, empty);
if (empty || item == null) {
setGraphic(null);
} else {
setGraphic(graphic);
assignment.setText(item.assignment);
caption.setText(item.caption);
caption.getStyleClass().remove("true");
if (item.eval) {
caption.getStyleClass().add("true");
}
}
}
});
To color the text you need to use the -fx-fill property instead of the -fx-text-fill property.
I am trying to change the color of the table rows when I set a boolean.
So I have this code:
boolean searchmode = false;
....
columns.forEach(c -> c.setCellFactory(column -> {
return new TableCell<ShowableInWarenkorb, String>() {
#Override
protected void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
setText(empty ? null : item);
if (searchmode) {
getStyleClass().add("searchmode");
} else{
getStyleClass().remove("searchmode");
}
}
};
}));
This CSS:
.searchmode {
-fx-background-color: rgba(153,153,153,0.3);
})
And then I switch searchmode eventually in my code before I am updating the table contents.
But the color does not change immediatley, sometimes I have to click a little bit around before it changes, how can I trigger it manually?
From your code, it looks like you want to apply this to all cells in the table. You can do this without a cell factory at all (though you may need one for other purposes).
Do
PseudoClass searchmodePseudoClass = PseudoClass.getPseudoClass("searchmode");
and then when you change the value of searchmode, do
table.pseudoClassStateChanged(searchmode);
In your css, do
.table-view:searchmode .table-cell {
-fx-background-color: rgba(153,153,153,0.3);
}
If you want to "automate" the update to the pseudoclass state, use a boolean property and add a listener:
private final BooleanProperty searchmode = new SimpleBooleanProperty(false);
public final boolean isSearchmode() {
return searchmodeProperty().get();
}
public final void setSearchmode(boolean searchmode) {
searchmodeProperty().set(searchmode);
}
public BooleanProperty searchmodeProperty() {
return searchmode ;
}
Then if you add the listener
searchmode.addListener((obs, wasSearchmode, isNowSearchmode) ->
table.pseudoClassStateChanged(searchmodePseudoClass, isNowSearchmode));
everything will be wired automatically so the table changes whenever you call setSearchmode(...).