javafxjavafx-11richtextfx

How to add responsiveness to richtext's codearea in javaFx?


Here's the code I'm getting frustrated with:

package com.example.notepad;

import javafx.fxml.FXML;
import javafx.scene.Node;
import javafx.scene.control.Alert;
import javafx.scene.control.Label;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import org.fxmisc.flowless.VirtualizedScrollPane;
import org.fxmisc.richtext.CodeArea;

import java.io.File;
import java.util.*;

public class core {

    @FXML
    private VBox editorContainer;

    private CodeArea codeArea;
    private File currentFile = null;
    private boolean isModified = false;

    private final Map<Integer, String> lineColorMap = new HashMap<>();
    private final Map<String, List<Integer>> colorGroups = new HashMap<>() {{
        put("YELLOW", new ArrayList<>());
        put("GREEN", new ArrayList<>());
        put("RED", new ArrayList<>());
    }};
    private final List<String> colorCycle = List.of("YELLOW", "GREEN", "RED", "NONE");

    private OptFile_handler fileHandler;

    @FXML
    public void initialize() {
        // Set up CodeArea with styling and line numbering
        codeArea = new CodeArea();
        codeArea.setFocusTraversable(true);
        codeArea.setStyle("-fx-font-family: 'Consolas'; -fx-font-size: 14px;");
        codeArea.setParagraphGraphicFactory(createLineNumberFactory());
        codeArea.textProperty().addListener((obs, oldText, newText) -> isModified = true);

        // Place CodeArea in a VirtualizedScrollPane
        VirtualizedScrollPane<CodeArea> vsPane = new VirtualizedScrollPane<>(codeArea);

        // Bind the scroll pane size to the container for responsiveness
        vsPane.prefWidthProperty().bind(editorContainer.widthProperty());
        vsPane.prefHeightProperty().bind(editorContainer.heightProperty());

        VBox.setVgrow(vsPane, Priority.ALWAYS);
        HBox.setHgrow(vsPane, Priority.ALWAYS);

        editorContainer.getChildren().add(vsPane);

        fileHandler = new OptFile_handler(this);
    }

    public java.util.function.IntFunction<Node> createLineNumberFactory() {
        return line -> {
            int lineIndex = line + 1;
            Label label = new Label(String.valueOf(lineIndex));
            label.setMinWidth(40);
            label.setPadding(new javafx.geometry.Insets(2, 8, 2, 8));
            label.setStyle(getLineNumberStyle(lineIndex));
            return label;
        };
    }
    }


    // Accessors for OptFile_handler file.
    public CodeArea getCodeArea() { return codeArea; }
    public File getCurrentFile() { return currentFile; }
    public void setCurrentFile(File file) { this.currentFile = file; }
    public boolean isModified() { return isModified; }
    public void setModified(boolean value) { this.isModified = value; }
    public VBox getEditorContainer() { return editorContainer; }

    public void refreshLineNumbers() {
        codeArea.setParagraphGraphicFactory(createLineNumberFactory());
    }
}

Below is the ui.fxml file code

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.*?>
<?import javafx.scene.layout.BorderPane?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.VBox?>

<!--    Handles the main stage ui   -->

<BorderPane xmlns:fx="http://javafx.com/fxml" fx:controller="com.example.temp.core">

    <center>
        <HBox>
            <VBox fx:id="editorContainer"/>
        </HBox>
    </center>
</BorderPane>

I have initialized codearea and in the left margin , there will be line numbering. so obviously some left padding will be there. But they are other things, Currently the codearea is not have correct height and width as per the window size(responsiveness).after resizing, the windows gets a new friend, that is empty area. but the codearea should have occupied it.

Needs : Basically a window in which i wanna add a codearea along with line numbering + heading menu bar. and i wanna do some custom things with the line numberings like on-click functions and all on that numbering. and i want responsiveness. I'm attaching an image as well window image

I have strong doubt in the initialize method. Kindly help me in solving this issue.

I tried taking help from chatgpt, copilot and other chatbots, but none were of any use. they rather helped in worsening the situation.


Solution

  • Needs : Basically a window in which i wanna add a codearea along with line numbering + heading menu bar.

    You can achieve this just with a BorderPane with the code area in the center. There is no need for the HBox and VBox. The MenuBar can be placed in the top of the BorderPane when you need it.

    Since a BorderPane resizes the node in the center to fill that region, when possible, this structure will achieve the responsiveness you need.

    Here is a version of the FXML and controller; I renamed some things to conform to standard naming conventions and removed references to classes and methods that were not shown in the OP.

    ui.fxml:

    <?xml version="1.0" encoding="UTF-8"?>
    
    <!--    Handles the main stage ui   -->
    
    <?import javafx.scene.layout.BorderPane?>
    <BorderPane fx:id="editorContainer" xmlns:fx="http://javafx.com/fxml" fx:controller="org.jamesd.examples.richtext.UIController">
    
    </BorderPane>
    

    UIController.java:

    package org.jamesd.examples.richtext;
    
    import javafx.fxml.FXML;
    import javafx.geometry.Insets;
    import javafx.scene.Node;
    import javafx.scene.control.Label;
    import javafx.scene.layout.BorderPane;
    import org.fxmisc.flowless.VirtualizedScrollPane;
    import org.fxmisc.richtext.CodeArea;
    
    import java.io.File;
    import java.util.*;
    public class UIController {
    
        @FXML
        private BorderPane editorContainer;
    
        private CodeArea codeArea;
        private File currentFile = null;
        private boolean isModified = false;
    
        private final Map<Integer, String> lineColorMap = new HashMap<>();
        private final Map<String, List<Integer>> colorGroups = new HashMap<>() {{
            put("YELLOW", new ArrayList<>());
            put("GREEN", new ArrayList<>());
            put("RED", new ArrayList<>());
        }};
        private final List<String> colorCycle = List.of("YELLOW", "GREEN", "RED", "NONE");
    
    
        @FXML
        public void initialize() {
            // Set up CodeArea with styling and line numbering
            codeArea = new CodeArea();
            codeArea.setFocusTraversable(true);
            codeArea.setStyle("-fx-font-family: 'Consolas'; -fx-font-size: 14px;");
            codeArea.setParagraphGraphicFactory(this::lineNumberView);
            codeArea.textProperty().addListener((obs, oldText, newText) -> isModified = true);
    
            // Place CodeArea in a VirtualizedScrollPane
            VirtualizedScrollPane<CodeArea> vsPane = new VirtualizedScrollPane<>(codeArea);
            editorContainer.setCenter(vsPane);
        }
        
        private Node lineNumberView(int lineNumber) {
            int lineIndex = lineNumber + 1;
            Label label = new Label(String.valueOf(lineIndex));
            label.setMinWidth(40);
            label.setPadding(new Insets(2, 8, 2, 8));
            return label;
        }
    
    
    }
    

    And a test application: HelloApplication.java

    package org.jamesd.examples.richtext;
    
    import javafx.application.Application;
    import javafx.fxml.FXMLLoader;
    import javafx.scene.Scene;
    import javafx.stage.Stage;
    
    import java.io.IOException;
    
    public class HelloApplication extends Application {
        @Override
        public void start(Stage stage) throws IOException {
            FXMLLoader fxmlLoader = new FXMLLoader(HelloApplication.class.getResource("ui.fxml"));
            Scene scene = new Scene(fxmlLoader.load(), 800, 800);
            stage.setTitle("Hello!");
            stage.setScene(scene);
            stage.show();
        }
    
        public static void main(String[] args) {
            launch();
        }
    }
    

    Why the original code doesn't work as desired.

    In a nutshell, the problem is that the VBox never grows to fill the width of the HBox. But here is what is happening in detail:

    A BorderPane will resize the node in its center region to fill that region, if possible.

    HBox and VBox, by default, resize their child nodes to their preferred sizes. This behavior can be modified:

    In this case you have a BorderPane with an HBox in the center. The HBox contains a VBox, which in turn contains the code editor.

    Since the HBox is in the center of the border pane, it will be resized by the border pane's layout mechanism to fill all the space allocated to the center of the border pane. (If the border pane is the root of the scene and there is nothing else in the border pane, this means the HBox will fill the entire scene.)

    The VBox will be sized by the HBox to its preferred size. None of the calls in the controller change this default behavior.

    The preferred size of the VBox is calculated from the preferred size of its child nodes; since the VBox only has one child node, the preferred size of the VBox is the preferred size of the code editor. The preferred size of the code editor, at least initially, is just its default (whatever that is).

    Consequently, at least initially, the size of the VBox is just the default preferred size of the code editor.

    The code

    VBox.setVgrow(vsPane, Priority.ALWAYS);
    

    will expand the vsPane vertically to fill the vertical space occupied by its containing VBox. However, this is what it would be anyway, since the vertical space occupied buy the VBox is the default preferred size of vsPane, as described above.

    The code

    HBox.setHGrow(vsPane, Priority.ALWAYS);`
    

    does nothing, since the parent of vsPane is not a HBox.

    The bindings also do nothing. What these will do in theory is to change the preferred size of vsPane to match the width and height of the VBox. However, the width and height of the VBox are determined by the preferred size of vsPane (as described above). Doing this is a bit dangerous, as it results in some circular dependencies and the result is not well defined. (You might be able to make some very bad things happen by setting padding on the VBox.) In this case, nothing happens, because nothing ever causes the width or height of the VBox to change, so the bindings are never invoked to change the preferred size of vsPane. So no sizes ever change.

    Generally speaking, binding the preferred sizes of nodes to values determined by other nodes is a bad idea. Use the layout panes to size nodes, not bindings.

    It's also not clear to me that there's ever a good reason to use a HBox or VBox with one child node (except possibly as the root node of a scene with just one node). So the solution above with vsPane in the center of the border pane and omitting the redundant HBox and VBox is the best solution given the stated requirements.

    If there is some reason you really need this structure (and again, I cannot think of any possible reason you would want this), you need:

    So the following works (but is full of useless and redundant code):

    <BorderPane xmlns:fx="http://javafx.com/fxml" fx:controller="org.jamesd.examples.richtext.UIController">
    
        <center>
            <HBox>
                <VBox HBox.hgrow="ALWAYS" fx:id="editorContainer"/>
            </HBox>
        </center>
    </BorderPane>
    
        public void initialize() {
            // Set up CodeArea with styling and line numbering
            codeArea = new CodeArea();
            codeArea.setFocusTraversable(true);
            codeArea.setStyle("-fx-font-family: 'Consolas'; -fx-font-size: 14px;");
            codeArea.setParagraphGraphicFactory(this::lineNumberView);
            codeArea.textProperty().addListener((obs, oldText, newText) -> isModified = true);
    
            // Place CodeArea in a VirtualizedScrollPane
            VirtualizedScrollPane<CodeArea> vsPane = new VirtualizedScrollPane<>(codeArea);
            VBox.setVgrow(vsPane, Priority.ALWAYS);
            editorContainer.getChildren().add(vsPane);
        }