Javafx Issue in dragging selected text from TextArea - javafx

Question

I have strange problem while dragging selected text from TextArea. The text is properly selected but when iam dragging to be place on the target position, the selection of text is changed, it reduce the selection for 2-3 characters randomly.
Here is the complete class :
public class DnDMainController extends Application {
ClipboardContent cb = new ClipboardContent();
ObservableList<String> list = FXCollections.observableArrayList();
#FXML
private TextArea sourceText;
#FXML
private ListView<String> listView;
#Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("/main/DnD.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
stage.setTitle("Simple Drag and Drop ExampleGame");
stage.show();
}
public static void main(String[] args) {
launch(args);
}
#FXML
void _detectDrag(MouseEvent event) {
Dragboard db = sourceText.startDragAndDrop(TransferMode.COPY);
cb.putString(sourceText.getSelectedText());
db.setContent(cb);
event.consume();
}
#FXML
void _dragExited(DragEvent event) {
String st = event.getDragboard().getString();
if (!(list.contains(st.trim()))) {
list.add(st);
listView.getItems().addAll(list);
}}
}
[![gif for DnD Issue][1]][1]
I have tried the same on TextField and it is working perfectly on TextField. But unfortunatelly i can not use the TextField due to large string of text. I dont know what Iam doing wrong...
FXML CODE:
<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="549.0" xmlns="http://javafx.com/javafx/10.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="main.DnDMainController">
<children>
<TextArea fx:id="sourceText" layoutY="273.0" onDragDetected="#_detectDrag" prefHeight="127.0" prefWidth="550.0" text="There was once a velveteen rabbit, and in the beginning he was really splendid. He was fat and bunchy, as a rabbit should be; his coat was spotted brown and white, he had real thread whiskers, and his ears were lined with pink sateen. On Christmas morning, when he sat wedged in the top of the Boy’s stocking, with a sprig of holly between his paws, the effect was charming." wrapText="true">
<font>
<Font size="19.0" />
</font></TextArea>
<ListView fx:id="listView" layoutY="40.0" onDragExited="#_dragExited" onMouseClicked="#_callContext" prefHeight="200.0" prefWidth="516.0" />
<Label alignment="CENTER" contentDisplay="CENTER" layoutX="-2.0" layoutY="2.0" prefHeight="38.0" prefWidth="550.0" text="List of Words" textAlignment="CENTER" />
<Label alignment="CENTER" contentDisplay="CENTER" layoutX="7.0" layoutY="240.0" prefHeight="32.0" prefWidth="542.0" text="Story" textAlignment="CENTER" />
</children>
</AnchorPane>```

Answer 1

I ran into a few problems trying to implement this in a straightforward way. I had to create a toggle that would allow me to select text and then drag the text. During the drag, I noticed that it would not grab all of the selected text unless the drag was started at the end of the selected text. I fixed that by grabbing the selected text after it was selected and the toggle mode is changed to drag mode. MCVE below.
Main
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.stage.Stage;
import javafx.scene.Parent;
public class Main extends Application {
#Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("Test.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
stage.setTitle("Simple Drag and Drop ExampleGame");
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
FXML
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.ListView?>
<?import javafx.scene.control.TextArea?>
<?import javafx.scene.control.ToggleButton?>
<?import javafx.scene.layout.AnchorPane?>
<AnchorPane id="AnchorPane" prefHeight="583.0" prefWidth="851.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="javaapplication12.TestController">
<children>
<ListView fx:id="listView" layoutX="326.0" layoutY="14.0" onDragDropped="#dragDropped" onDragEntered="#dragEntered" onDragOver="#dragOver" prefHeight="200.0" prefWidth="200.0" />
<TextArea fx:id="textArea" layoutX="224.0" layoutY="274.0" onDragDetected="#dragDetected" prefHeight="247.0" prefWidth="426.0" text="There was once a velveteen rabbit, and in the beginning he was really splendid. He was fat and bunchy, as a rabbit should be; his coat was spotted brown and white, he had real thread whiskers, and his ears were lined with pink sateen. On Christmas morning, when he sat wedged in the top of the Boy’s stocking, with a sprig of holly between his paws, the effect was charming." wrapText="true" />
<ToggleButton fx:id="tbtnDragMode" layoutX="44.0" layoutY="26.0" mnemonicParsing="false" onAction="#handleTbtnDragMode" text="Select Text Mode" />
</children>
</AnchorPane>
Controller
import java.net.URL;
import java.util.ResourceBundle;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.ListView;
import javafx.scene.control.TextArea;
import javafx.scene.control.ToggleButton;
import javafx.scene.input.ClipboardContent;
import javafx.scene.input.DragEvent;
import javafx.scene.input.Dragboard;
import javafx.scene.input.MouseEvent;
import javafx.scene.input.TransferMode;
public class TestController implements Initializable {
#FXML TextArea textArea;
#FXML ListView listView;
#FXML ToggleButton tbtnDragMode;
ObservableList<String> list = FXCollections.observableArrayList();
String selectedText = "";
#Override
public void initialize(URL url, ResourceBundle rb) {
listView.setItems(list);
list.add("test");
}
#FXML private void handleTbtnDragMode(ActionEvent actionEvent)
{
if(tbtnDragMode.isSelected())
{
System.out.println("Drag Mode On");
tbtnDragMode.setText("Drag Mode");
selectedText = textArea.getSelectedText().isBlank() ? "" : textArea.getSelectedText();
}
else {
System.out.println("Drag Mode Off");
tbtnDragMode.setText("Select Text Mode");
}
}
#FXML
private void dragDetected(MouseEvent event) {
System.out.println("drag detected 1");
System.out.println(tbtnDragMode.isSelected());
if(tbtnDragMode.isSelected())
{
System.out.println("drag detected 2");
/* drag was detected, start a drag-and-drop gesture*/
/* allow any transfer mode */
Dragboard db = textArea.startDragAndDrop(TransferMode.ANY);
/* Put a string on a dragboard */
ClipboardContent content = new ClipboardContent();
content.putString(selectedText);
db.setContent(content);
event.consume();
}
}
#FXML
private void dragEntered(DragEvent event) {
System.out.println("dragEntered");
event.consume();
}
#FXML
private void dragDropped(DragEvent event)
{
System.out.println("Drag dropped");
/* data dropped */
/* if there is a string data on dragboard, read it and use it */
Dragboard db = event.getDragboard();
boolean success = false;
if (db.hasString()) {
list.add(db.getString());
success = true;
}
/* let the source know whether the string was successfully
* transferred and used */
event.setDropCompleted(success);
event.consume();
}
#FXML
private void dragDone(DragEvent event) {
/* the drag and drop gesture ended */
/* if the data was successfully moved, clear it */
System.out.println("drag done");
if (event.getTransferMode() == TransferMode.MOVE) {
//clear textarea selection
System.out.println("drag done");
}
event.consume();
}
#FXML
private void dragExited(DragEvent event) {
System.out.println("dragExited");
event.consume();
}
#FXML
private void dragOver(DragEvent event) {
/* data is dragged over the target */
/* accept it only if it is not dragged from the same node
* and if it has a string data */
System.out.println(event.getGestureSource() + " - " + event.getTarget());
if (event.getGestureSource() != event.getTarget() &&
event.getDragboard().hasString()) {
/* allow for both copying and moving, whatever user chooses */
event.acceptTransferModes(TransferMode.COPY_OR_MOVE);
}
event.consume();
}
}