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Thread: Dragging Undercoated Window Causes Glitching

  1. #1
    Junior Member
    Join Date
    Jul 2019
    Thanked 0 Times in 0 Posts

    Default Dragging Undercoated Window Causes Glitching

    Hey could use a little help on a Post-It-Note project I'm just finishing up. It's a small program that only has one other class than Main.

    The PostIt class creates a new Undercoated JavaFX Stage and calls stage.show() on creation, making a new post-it. A button in the main class creates objects from this PostIt class and adds them to an ArrayList also in the Main class.

    As the window is Undercoated I needed a way to drag the PostIt windows around and I found some code online. This code is commented with "***" in the PostIt class.

    So the problem is it dose kind of work... but it mainly just glitches the window around the screen as you try to drag it to a new position. I have no I idea why this is happening...

    Main Class:
    package com.company;
    import javafx.application.Application;
    import javafx.event.ActionEvent;
    import javafx.event.EventHandler;
    import javafx.scene.control.ComboBox;
    import javafx.stage.Stage;
    import javafx.scene.control.Button;
    import javafx.scene.layout.AnchorPane;
    import javafx.scene.Scene;
    import java.util.*;
    public class Main extends Application{
        //Cpntains PostIt Objects used to create new note window
        ArrayList<PostIt> notes = new ArrayList<PostIt>();
        public static void main(String [] args){
        public void start(Stage primaryStage) throws Exception {
            primaryStage.setTitle("Winodw Title!!!");
            //Button for creating new note and adding it to notes array
            Button b1 = new Button();
            b1.setText("New Note");
            //drop down box for selecting color of nate
            ComboBox comboBox = new ComboBox();
            //Make new note logic
            b1.setOnAction(new EventHandler<ActionEvent>() {
                @Override public void handle(ActionEvent e) {
                    //holds new note
                    PostIt newpost = null;
                    //note id
                    int id = 0;
                    //get color from combobox
                    String color;
                    color = (String) comboBox.getValue();
                    //checks notes array length to calculate ID of new note
                    if (notes.size() != 0){
                        int temp = notes.size() - 1;
                        id = notes.get(temp).getId() + 1;
                    try {
                        newpost = new PostIt(primaryStage, id, color);
                    } catch (Exception ex) {
                    //add note to notes list
            //layout and stage
            AnchorPane layout = new AnchorPane();
            AnchorPane.setTopAnchor(comboBox, 40.0);
            Scene scene = new Scene(layout, 300, 250);

    PostIt Class:
    package com.company;
    import javafx.application.Application;
    import javafx.event.EventHandler;
    import javafx.scene.Scene;
    import javafx.scene.control.TextArea;
    import javafx.scene.input.MouseEvent;
    import javafx.scene.layout.AnchorPane;
    import javafx.scene.layout.HBox;
    import javafx.scene.paint.Color;
    import javafx.scene.text.Font;
    import javafx.stage.Stage;
    import javafx.stage.StageStyle;
    import java.util.Random;
    public class PostIt extends Application {
        //post-it stage
        Stage stage;
        int id;
        //used for drag window logic
        Double xOffset = 0.00;
        Double yOffset = 0.00;
        //color logic veriables
        String color;
        String hexcolor1;
        String hexcolor2;
        public PostIt(Stage primaryStage, int id, String color) throws Exception {
            //set ID and color
            this.id = id;
            this.color = color;
            //if color is random - roll and set new color
            if (this.color.equals("Random")){
                int rand = getRandomNumberInRange(1,4);
                if (rand == 1) this.color = "Blue";
                else if (rand == 2) this.color = "Green";
                else if (rand == 3) this.color = "Purple";
                else if (rand == 4) this.color = "Yellow";
            //set color values
            if (this.color.equals("Blue")){
                hexcolor1 = "#73ADEC";
                hexcolor2 = "#A0CCF9";
            else if (this.color.equals("Green")){
                hexcolor1 = "#C6E951";
                hexcolor2 = "#DDF681";
            else if (this.color.equals("Purple")){
                hexcolor1 = "#E86BCF";
                hexcolor2 = "#FA94E8";
            else if (this.color.equals("Yellow")){
                hexcolor1 = "#F0CC40";
                hexcolor2 = "#FAE278";
            //start stage
            stage = new Stage();
        public void start(Stage stage) throws Exception {
            //fix stage size
            //create textbox and set color - hexcolor2
            TextArea textArea = new TextArea();
            textArea.setFont(Font.font("Comic Sans MS", 22));
            textArea.setStyle("-fx-focus-color: transparent; -fx-text-box-border: transparent;");
            textArea.setStyle("-fx-background-color: green");
            textArea.setStyle("-fx-control-inner-background:" + hexcolor2 + ";");
            //Set layout and color - hexcolor1
            AnchorPane pane = new AnchorPane(textArea);
            pane.styleProperty().set("-fx-background-color: " + hexcolor1);
            //set textArea location
            AnchorPane.setTopAnchor(textArea, 80.0);
            AnchorPane.setLeftAnchor(textArea, 0.0);
            //*****************Code for dragging window*****************
            pane.setOnMousePressed(new EventHandler<MouseEvent>() {
                public void handle(MouseEvent event) {
                        xOffset = stage.getX() - event.getSceneX();
                        yOffset = stage.getY() - event.getScreenY();
            pane.setOnMouseDragged(new EventHandler<MouseEvent>() {
                public void handle(MouseEvent event) {
                        stage.setX(event.getSceneX() - xOffset);
                        stage.setY(event.getSceneY() - yOffset);
            //*****************End of code for Dragging window*****************
            Scene scene = new Scene(pane, 400, 400, Color.BLACK);
            //System.out.println("" + getId());
        public int getId() {
            return id;
        public void setId(int id) {
            this.id = id;
        private static int getRandomNumberInRange(int min, int max) {
            if (min >= max) {
                throw new IllegalArgumentException("max must be greater than min");
            Random r = new Random();
            return r.nextInt((max - min) + 1) + min;

    --- Update ---

    Fixed it. I was using getSceanX/Y and not getScreenX/Y. Also there was a small mistake in the math.

    pane.setOnMousePressed(new EventHandler<MouseEvent>() {
                public void handle(MouseEvent event) {
                        xOffset = event.getScreenX() - stage.getX();
                        yOffset = event.getScreenY() - stage.getY();
            pane.setOnMouseDragged(new EventHandler<MouseEvent>() {
                public void handle(MouseEvent event) {
                        stage.setX(event.getScreenX() - xOffset);
                        stage.setY(event.getScreenY() - yOffset);
    Last edited by Blick; March 19th, 2020 at 04:21 PM.

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