Develop Reference

Click Button to activate EventListener to get only next key pressed

I am making a Tetris clone with JavaFX, and what I am "trying to do is allow the user to configure custom key bindings for specific actions." I am not using a FXML file or controllers; I am using Java JDK 8.
I am making a "Set Custom Controls" menu, using Stage and Scene. I want to list all the different controls in Labels with a Button next to each.
When the user clicks a Button, I want that to activate an EventListener<KeyEvent> to grab just the first key pressed after clicking that Button in order to assign that KeyCode to the corresponding `KeyCode class variable.
Also, if the user decides they made a mistake clicking the Button, I want to allow them to click the Button again to cancel the EventListener<KeyEvent>.

As suggested in a comment by #Slaw, you want to "allow the user to configure custom key bindings for specific actions." One approach would be "a key-event editor for JavaFX like the one cited here for Swing."
The example below focuses narrowly on capturing raw key presses. As suggested here, a KeyEvent listener captures the user's keystroke, displaying the name of the game event and updating the pressed key code's name. KeyCode.TAB is reserved for navigation, and the rest are consumed. The resulting key event and game event are stored in a Map for later reference. As #James_D comments, typical usage would "never use a key listener with a text input control." In this case, the focused, but non-editable TextField conveniently displays the pressed key's name.
import java.util.HashMap;
import java.util.Map;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyEvent;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
/** #see https://stackoverflow.com/a/73130018/230513 */
public class KeyCodeSelector extends Application {
private final Map<KeyEvent, String> map = new HashMap<>();
#Override
public void start(Stage stage) {
var root = new VBox();
root.getChildren().add(createKeyPane("Left: ", KeyCode.LEFT));
root.getChildren().add(createKeyPane("Right: ", KeyCode.RIGHT));
var scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
private Pane createKeyPane(String s, KeyCode k) {
var label = new Label(s);
label.setAlignment(Pos.BASELINE_RIGHT);
label.setMinWidth(50);
var textField = new TextField(k.getName());
label.setLabelFor(textField);
textField.setEditable(false);
textField.setOnKeyPressed((keyEvent) -> {
var keyCode = keyEvent.getCode();
if (keyCode != KeyCode.TAB) {
textField.setText(keyCode.getName());
map.put(keyEvent, s);
keyEvent.consume();
}
});
var grid = new GridPane();
grid.add(label, 0, 0);
grid.add(textField, 0, 1);
return new HBox(label, textField);
}
public static void main(String[] args) {
launch();
}
}

I will share my solution for anyone who runs into problem. I will use my implementation for setting the key binding for moving a block left.
I created the class variables:
private Scene sceneControlOptions;
private EventHandler<KeyEvent> keyHandlerBtnMoveLeft;
private Button btnMoveLeft;
private KeyCode controlButtonMoveLeft;
Inside the method to create and display my control options menu (Stage and Scene):
btnMoveLeft.setOnMouseClicked(e -> {
btnMoveLeft.setText("---");
sceneControlOptions.addEventHandler(KeyEvent.KEY_PRESSED, keyHandlerBtnMoveLeft);
});
And finally, inside of start() I added:
keyHandlerBtnMoveLeft = new EventHandler<KeyEvent>() {
#Override
public void handle(KeyEvent event) {
KeyCode key = event.getCode();
setControlButtonMoveLeft(key);
btnMoveLeft.setText(key.getName().toString());
sceneControlOptions.removeEventHandler(KeyEvent.KEY_PRESSED, keyHandlerBtnMoveLeft);
}
};
Where setControlButtonMoveLeft(key) is:
private void setControlButtonMoveLeft(KeyCode key) {
this.controlButtonMoveLeft = key;
}

How to scale Label within a ListView in JavaFX

I have a ListView with some Labels in it. The labels' width property is bound to the width property of the ListView but they seem to be slightly larger meaning that a horizontal scrollbar is shown on the list view. What I want is to fit the labels in the list view without the scrollbar on the bottom. I have looked at various padding and insets values on both the label and the list view but none I have found are the culprit (most are zero).
Here is an example which demonstrates the problem.
import javafx.application.Application;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.ListView;
import javafx.stage.Stage;
public class ListViewScrollExample extends Application {
private ListView<Node> listView;
#Override
public void start(Stage stage) throws Exception {
listView = new ListView<>();
addItem("Some quite long string to demonstrate the problem");
Scene scene = new Scene(listView);
stage.setScene(scene);
stage.show();
}
public void addItem(String item) {
Label label = new Label(item);
label.setWrapText(true);
label.maxWidthProperty().bind(listView.widthProperty());
listView.getItems().add(label);
}
public static void main(String[] args){
Application.launch(args);
}
}

The default CSS file adds padding to a ListCell (line 2316 in the current release):
.list-cell {
-fx-padding: 0.25em 0.583em 0.25em 0.583em; /* 3 7 3 7 */
}
It generally a bad idea to use Node instances as the data backing a ListView: you should use String in this example, and use the cell factory to create a label displaying the string that is configured as you need. The following seems to work for your example:
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.scene.Scene;
import javafx.scene.control.ContentDisplay;
import javafx.scene.control.Label;
import javafx.scene.control.ListCell;
import javafx.scene.control.ListView;
import javafx.stage.Stage;
public class ListViewScrollExample extends Application {
private ListView<String> listView;
#Override
public void start(Stage stage) throws Exception {
listView = new ListView<>();
listView.getItems().add("Some quite long string to demonstrate the problem");
listView.setCellFactory(lv -> {
ListCell<String> cell = new ListCell<String>() {
private Label label = new Label();
{
label.setWrapText(true);
label.maxWidthProperty().bind(Bindings.createDoubleBinding(
() -> getWidth() - getPadding().getLeft() - getPadding().getRight() - 1,
widthProperty(), paddingProperty()));
setContentDisplay(ContentDisplay.GRAPHIC_ONLY);
}
#Override
protected void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
if (empty) {
setGraphic(null);
} else {
label.setText(item);
setGraphic(label);
}
}
};
return cell ;
});
Scene scene = new Scene(listView);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args){
Application.launch(args);
}
}
Here I created a list cell that displays a label as its graphic, with the text of the label set to the string to be displayed. The constructor for the cell binds the label's max width to the width of the cell, less any space required for padding. The call to setContentDisplay(ContentDisplay.GRAPHIC_ONLY) appears necessary, so the cell doesn't try to allocate any space for text.
It may be possible to do this by setting the text directly on the list cell and calling setWrapText(true) on the cell (which is, after all, also a subclass of Labeled), but I couldn't get it to work this way.

I couldn't replicate the problem but you can try the following instead of label.maxWidthProperty().bind(listView.widthProperty());
double i = Double.parseDouble(listView.widthProperty().toString());
label.setMaxWidth((i-2.0));
You can change the 2.0 to any pixel count you need to alter the screen by.

How to make a ListView selectable but not editable

so I'm writing a javafx app and I need to be able to select the cells from the list view (for copy paste purposes) but I don't want to make it editable, I mean, the content cannot be changed unless I want to (allowing it through a button, for example).
So I have the following code:
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.scene.Scene;
import javafx.scene.control.ListView;
import javafx.scene.control.cell.TextFieldListCell;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class Main extends Application {
#Override
public void start(Stage primaryStage) throws Exception{
List<String> contacts = new ArrayList<>(Arrays.asList("968787522","3424234234","2343234324"));
ListView<String> contactsList = new ListView();
contactsList.setItems(FXCollections.observableArrayList(contacts));
//this gives me the ability to edit the row as text field but I want this text field to not be editable
contactsList.setCellFactory(TextFieldListCell.forListView());
StackPane pane = new StackPane();
pane.getChildren().add(contactsList);
primaryStage.setScene(new Scene(pane, 300, 275));
primaryStage.show(); }
public static void main(String[] args) {
launch(args);
}
}
and if I set 'contactsList' as not editable, I'm not able to edit, neither select.
As you can see (image bellow),I'm editing the cell, but I want to be able to select the text(not the item), but I don't want to be able to delete characters (text selectable but not editable).

so after breaking my head off, lots of research and API reading, I came up with a solution. This does EXACTLY what I wanted to do. Here is the demo if someone needs it ;)
So the idea is, each time we want to select the content of a row we need to select the row, get the textField and set the editing to true or false, (every time).
So in the demo that I made, I placed a button so you can toggle the editing to true or false to be sure that's is working, and how is working.
Cheers.
I commented some of the code for better understanding, if you have any questions about this just let me know.
package sample;
import com.sun.javafx.scene.control.skin.VirtualFlow;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.collections.FXCollections;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.cell.TextFieldListCell;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class Main extends Application {
private boolean editable = false;
public static IndexedCell getCell(final Control control, final int index) {
return getVirtualFlow(control).getCell(index);
}
public static VirtualFlow<?> getVirtualFlow(Control control) {
Group group = new Group();
Scene scene = new Scene(group);
Stage stage = new Stage();
if(control.getScene() == null) {
group.getChildren().setAll(control);
stage.setScene(scene);
stage.show();
}
VirtualFlow<?>flow = (VirtualFlow<?>) control.lookup("#virtual-flow");
return flow;
}
public void setEditable(ListView contactsList){
//this needs to be done since we need to run our code after the text field was rendered
//so we need to invoke our code after this happens, if not it will throw a null pointer...
Platform.runLater(() -> {
//this is one of the most important guys because javafx api says that
//TextFieldListCell.forListView() allows editing of the cell content when the cell is double-clicked,
// or when {#link ListView#edit(int)} is called.
int rowIndex = contactsList.getSelectionModel().getSelectedIndex();
contactsList.edit(rowIndex);
ListCell rootCell = (ListCell) getCell(contactsList, rowIndex);
TextField textField = (TextField) rootCell.getGraphic();
textField.setEditable(editable);
});
}
#Override
public void start(Stage primaryStage) throws Exception{
List<String> contacts = new ArrayList<>(Arrays.asList("968787522","3424234234","2343234324"));
ListView<String> contactsList = new ListView();
contactsList.setItems(FXCollections.observableArrayList(contacts));
contactsList.setEditable(true);
//this gives me the ability to edit the row as text field but I want this text field to not be editable
contactsList.setCellFactory(TextFieldListCell.forListView());
contactsList.setOnEditStart(e -> {
setEditable(contactsList);
});
StackPane pane = new StackPane();
Button editBtn = new Button("Toggle edit");
editBtn.setOnAction(event -> {
editable = !editable;
editBtn.setText("Editing = " + editable);
//to cancel any editing that might be occuring
contactsList.getSelectionModel().clearSelection();
});
pane.getChildren().addAll(contactsList,editBtn);
primaryStage.setScene(new Scene(pane, 300, 275));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}

If I understand you correctly, it is not necessary to set the listview to 'not editable', as the default behaviour should suffice for your purpose. Take a look at this code, for example:
import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.ListView;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
public class NewFXMain extends Application {
#Override
public void start(Stage primaryStage) {
ListView listView = new ListView();
listView.getItems().addAll("one","two","three","four");
listView.setOnMouseClicked(new EventHandler<MouseEvent>() {
#Override
public void handle(MouseEvent event) {
System.out.println(listView.getSelectionModel().getSelectedItem());
}
});
StackPane root = new StackPane();
root.getChildren().add(listView);
Scene scene = new Scene(root, 300, 250);
primaryStage.setTitle("ListView Example");
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
I changed nothing about the editable-property of the ListView, but I can select every item, without being able to edit it (in the sense of changing its value). You can easily add an EventHandler to the ListView to perform whatever operation you want to perform. You could also add an EventHandler to every cell of the ListView by manipulating the CellFactory, as shown in this answer: How to handle ListView item clicked action?

Here's what works for me:
TableView<DataBean> table = new TableView<>();
table.setItems(...); // list of some DataBean objects with dataBeanField proprty
table.setEditable(true);
TableColumn<DataBean, String> column = new TableColumn<>("SomeData");
column.setCellValueFactory(new PropertyValueFactory<DataBean, String>("dataBeanField"));
column.setCellFactory(new Callback<TableColumn<DataBean, String>, TableCell<DataBean, String>>() {
#Override
public TableCell<DataBean, String> call(TableColumn<DataBean, String> param) {
return new TextFieldTableCell<>(new DefaultStringConverter() {
private String defaultValue = "";
#Override
public String fromString(String newValue) {
return super.fromString(defaultValue);
}
#Override
public String toString(String value) {
return defaultValue = super.toString(value);
}
});
}
});

Detect URL change in JavaFX WebView

In JavaFX's WebView I am struggling to detect change in URL.
I have this method in a class:
public Object urlchange() {
engine.getLoadWorker().stateProperty().addListener(new ChangeListener<State>() {
#Override
public void changed(ObservableValue ov, State oldState, State newState) {
if (newState == Worker.State.SUCCEEDED) {
return engine.getLocation());
}
}
});
}
and I am trying to use it for an object called loginbrowser like:
System.out.print(loginbrowser.urlchange());
Can you see what I've done wrong?

(Part of) what you are doing wrong
The code you provided in your question doesn't even compile. The changed method of a ChangeListener is a void function, it can't return any value.
Anyway, loading of stuff in a web view is an asynchronous process. If you want the value of the location of the web view after the web view has loaded, you need to either wait for the load to complete (inadvisable on the JavaFX application thread, as that would hang your application until the load is complete), or be notified in a callback that the load is complete (which is what the listener you have is doing).
(Probably) what you want to do
Bind some property to the location property of the web engine. For example:
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.scene.web.*;
import javafx.stage.Stage;
public class LocationViewer extends Application {
#Override
public void start(Stage stage) throws Exception {
Label location = new Label();
WebView webView = new WebView();
WebEngine engine = webView.getEngine();
engine.load("http://www.fxexperience.com");
location.textProperty().bind(engine.locationProperty());
Scene scene = new Scene(new VBox(10, location, webView));
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
The above code will update the location label whenever the location of the web view changes (try it by running the code then clicking on some links). If you wish to only update the label once a page has successfully loaded, then you need a listener based upon the WebView state, for example:
import javafx.application.Application;
import javafx.concurrent.Worker;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.scene.web.*;
import javafx.stage.Stage;
public class LocationAfterLoadViewer extends Application {
#Override
public void start(Stage stage) throws Exception {
Label location = new Label();
WebView webView = new WebView();
WebEngine engine = webView.getEngine();
engine.load("http://www.fxexperience.com");
engine.getLoadWorker().stateProperty().addListener((observable, oldValue, newValue) -> {
if (Worker.State.SUCCEEDED.equals(newValue)) {
location.setText(engine.getLocation());
}
});
Scene scene = new Scene(new VBox(10, location, webView));
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
If you run the last program and click on some links, you will notice it delays the updating of the location label until after the pages you click on completely finish loading, as opposed to the first program which updates the label as soon as the location changes, regardless of whether the load takes a while or indeed works at all.
Answers to additional questions
How can I use the url value in the label in a conditional statement? I want an action to be preformed if it changed from the original one.
location.textProperty().addListener((observable, oldValue, newValue) -> {
// perform required action.
});

registering mouse handler but handler not inline, in javafx

I have an app in JavaFX that is getting a bit large, and I want to keep the code readable.
I have a LineChart that I want to have zoom functionality built in, that occurs on a mouseclick. I know I need to register a mouse listener to the chart. What I cannot figure out from Oracle examples, ie as written here:
http://docs.oracle.com/javafx/2/events/handlers.htm
is how to NOT have my handler defined inline to the registering. In other words, I want the body of the handler (which is many lines of code) to be in another class. Can I do that? And if so, how do I register the handler to my chart in my main Javafx controller code?

Place your handler in a new class which implements the the Mouse EventHandler and register an instance of your class with your target node via the node's setOnClicked method.
import javafx.application.Application;
import javafx.event.EventHandler;
import javafx.scene.*;
import javafx.scene.image.ImageView;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
/**
* JavaFX sample for registering a click handler defined in a separate class.
* http://stackoverflow.com/questions/12326180/registering-mouse-handler-but-handler-not-inline-in-javafx
*/
public class ClickHandlerSample extends Application {
public static void main(String[] args) { launch(args); }
#Override public void start(final Stage stage) throws Exception {
stage.setTitle("Left click to zoom in, right click to zoom out");
ImageView imageView = new ImageView("http://upload.wikimedia.org/wikipedia/commons/b/b7/Idylls_of_the_King_3.jpg");
imageView.setPreserveRatio(true);
imageView.setFitWidth(150);
imageView.setOnMouseClicked(new ClickToZoomHandler());
final StackPane layout = new StackPane();
layout.getChildren().addAll(imageView);
layout.setStyle("-fx-background-color: cornsilk;");
stage.setScene(new Scene(layout, 400, 500));
stage.show();
}
private static class ClickToZoomHandler implements EventHandler<MouseEvent> {
#Override public void handle(final MouseEvent event) {
if (event.getSource() instanceof Node) {
final Node n = (Node) event.getSource();
switch (event.getButton()) {
case PRIMARY:
n.setScaleX(n.getScaleX()*1.1);
n.setScaleY(n.getScaleY()*1.1);
break;
case SECONDARY:
n.setScaleX(n.getScaleX()/1.1);
n.setScaleY(n.getScaleY()/1.1);
break;
}
}
}
}
}