Jslider reflected in pannel

Question

I don't know why, although I am trying to make a color picker and for some reason the slider gets reflected in the panel, if I use one of the sliders and resize the frame the thing disappears.

Here is what I see:

I tried to change how different components are rendered, I tried to change the change listener, I tried to change as well the panel, but nothing changed.

I used repaint and tried not to use repaint.

This is my code:

import java.awt.BorderLayout;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import java.awt.GridBagLayout;
import javax.swing.JSlider;
import java.awt.GridBagConstraints;
import java.awt.Insets;
import java.awt.Color;
import java.awt.GridLayout;
import javax.swing.JButton;
import javax.swing.JLabel;
import java.awt.FlowLayout;
import javax.swing.BoxLayout;
import net.miginfocom.swing.MigLayout;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;

public class ThemeBuilder extends JFrame {

    private JPanel contentPane;
    private JPanel colorShow;
    private JPanel pnlButtons;
    private JPanel pnlSldG;
    private JPanel pnlSldB;
    private JPanel pnlSldAlpha;
    private JPanel pnlSldR;
    private JButton btnBackground;
    private JButton btnText;
    private JButton btnPanels;
    private JButton btnButtonsText;
    private JButton btnSideList;
    private JButton btnButtonLabels;
    private JButton btnButtonContours;
    private JButton btnSideListForeground;
    private JButton btnForeground;
    private JLabel label;
    private JSlider sldG;
    private JSlider sldB;
    private JSlider sldAlpha;
    private JSlider sldR;
    private JMenuBar menuBar;
    private JMenuItem mntmFile;



    /**
     * Create the frame.
     */
    public ThemeBuilder() {
        makeSliders();
        makeBtns();
        makePnls();
        makeFrame();
    }

    private void makeFrame(){
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 431, 476);
        menuBar = new JMenuBar();
        setJMenuBar(menuBar);
        mntmFile = new JMenuItem("File");
        menuBar.add(mntmFile);
    }


    private void makePnls(){

        pnlButtons = new JPanel();
        GridBagConstraints gbc_pnlButtons = new GridBagConstraints();
        gbc_pnlButtons.gridwidth = 2;
        gbc_pnlButtons.anchor = GridBagConstraints.NORTH;
        gbc_pnlButtons.gridx = 0;
        gbc_pnlButtons.gridy = 5;
        pnlButtons.setLayout(new MigLayout("", "[97px][71px][95px][113px][79px][89px][111px]", "[23px][][][][][][][][]"));

        pnlSldB = new JPanel();
        GridBagConstraints gbc_pnlSldB = new GridBagConstraints();
        gbc_pnlSldB.anchor = GridBagConstraints.NORTH;
        gbc_pnlSldB.insets = new Insets(0, 0, 5, 5);
        gbc_pnlSldB.fill = GridBagConstraints.HORIZONTAL;
        gbc_pnlSldB.gridx = 0;
        gbc_pnlSldB.gridy = 3;

        colorShow = new JPanel();
        colorShow.setBackground(Color.GRAY);
        GridBagConstraints gbc_colorShow = new GridBagConstraints();
        gbc_colorShow.gridheight = 3;
        gbc_colorShow.insets = new Insets(0, 0, 5, 0);
        gbc_colorShow.fill = GridBagConstraints.BOTH;
        gbc_colorShow.gridx = 1;
        gbc_colorShow.gridy = 1;
        colorShow.setOpaque(true);
        colorShow.setDoubleBuffered(true);


        pnlSldG = new JPanel();
        GridBagConstraints gbc_pnlSldG = new GridBagConstraints();
        gbc_pnlSldG.gridheight = 2;
        gbc_pnlSldG.insets = new Insets(0, 0, 5, 5);
        gbc_pnlSldG.fill = GridBagConstraints.BOTH;
        gbc_pnlSldG.gridx = 0;
        gbc_pnlSldG.gridy = 1;


        pnlSldR = new JPanel();
        GridBagConstraints gbc_pnlSldR = new GridBagConstraints();
        gbc_pnlSldR.insets = new Insets(0, 0, 5, 5);
        gbc_pnlSldR.fill = GridBagConstraints.BOTH;
        gbc_pnlSldR.gridx = 0;
        gbc_pnlSldR.gridy = 0;


        pnlSldAlpha = new JPanel();
        GridBagConstraints gbc_pnlSldAlpha = new GridBagConstraints();
        gbc_pnlSldAlpha.insets = new Insets(0, 0, 5, 5);
        gbc_pnlSldAlpha.fill = GridBagConstraints.BOTH;
        gbc_pnlSldAlpha.gridx = 0;
        gbc_pnlSldAlpha.gridy = 4;

        pnlSldR.add(sldR);
        pnlSldG.add(sldG);
        pnlSldB.add(sldB);
        pnlSldAlpha.add(sldAlpha);
        pnlButtons.add(btnButtonLabels, "cell 0 0,alignx left,aligny center");
        pnlButtons.add(btnButtonContours, "cell 1 0,alignx left,aligny center");
        pnlButtons.add(label, "cell 4 0,alignx left,aligny center");
        pnlButtons.add(btnButtonsText, "cell 0 1,alignx left,aligny center");
        pnlButtons.add(btnText, "cell 0 3,alignx left,aligny center");
        pnlButtons.add(btnPanels, "cell 1 3,alignx left,aligny center");
        pnlButtons.add(btnSideListForeground, "cell 0 5");
        pnlButtons.add(btnSideList, "cell 1 5,alignx left,aligny center");
        pnlButtons.add(btnBackground, "cell 0 8,alignx left,aligny center");
        pnlButtons.add(btnForeground, "cell 1 8");

        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        GridBagLayout gbl_contentPane = new GridBagLayout();
        gbl_contentPane.columnWidths = new int[]{0, 0, 0};
        gbl_contentPane.rowHeights = new int[]{0, 0, 0, 0, 0, 0, 0};
        gbl_contentPane.columnWeights = new double[]{1.0, 1.0, Double.MIN_VALUE};
        gbl_contentPane.rowWeights = new double[]{1.0, 0.0, 0.0, 0.0, 0.0, 0.0, Double.MIN_VALUE};
        contentPane.setLayout(gbl_contentPane);

        contentPane.add(pnlButtons, gbc_pnlButtons);
        contentPane.add(pnlSldB, gbc_pnlSldB);
        contentPane.add(colorShow, gbc_colorShow);
        contentPane.add(pnlSldG, gbc_pnlSldG);
        contentPane.add(pnlSldR, gbc_pnlSldR);
        contentPane.add(pnlSldAlpha, gbc_pnlSldAlpha);

        pnlButtons.repaint();
        pnlSldAlpha.repaint();
        pnlSldR.repaint();
        pnlSldB.repaint();
        pnlSldG.repaint();
        btnPanels.repaint();
        contentPane.repaint();

    }

    private void makeSliders(){
        sldR = new JSlider();
        sldR.setMaximum(240);
        sldR.setMajorTickSpacing(50);
        sldR.setSnapToTicks(true);
        sldR.setPaintTicks(true);
        sldR.setPaintLabels(true);
        sldR.setValue(104);

        sldG = new JSlider();
        sldG.setMaximum(240);
        sldG.setSnapToTicks(true);
        sldG.setPaintTicks(true);
        sldG.setPaintLabels(true);
        sldG.setMajorTickSpacing(50);
        sldG.setValue(104);

        sldB = new JSlider();
        sldB.setMaximum(240);
        sldB.setSnapToTicks(true);
        sldB.setPaintTicks(true);
        sldB.setPaintLabels(true);
        sldB.setMajorTickSpacing(50);
        sldB.setValue(104);

        sldAlpha = new JSlider();
        sldAlpha.setMaximum(240);
        sldAlpha.setSnapToTicks(true);
        sldAlpha.setPaintTicks(true);
        sldAlpha.setPaintLabels(true);
        sldAlpha.setMajorTickSpacing(50);
        sldAlpha.setValue(240);
    }


    private void makeBtns(){
        btnButtonLabels = new JButton("Button Labels");
        btnButtonContours = new JButton("Button Contours");
        label = new JLabel("");
        btnButtonsText = new JButton("Buttons Text");
        btnText = new JButton("Top Menu Labels");
        btnPanels = new JButton("Top Menu");
        btnSideListForeground = new JButton("Side List Foreground");
        btnSideList = new JButton("Side List Background");
        btnBackground = new JButton("Background");
        btnForeground = new JButton("Foreground");
    }


    public JPanel getContentPane() {
        return contentPane;
    }

    protected JPanel getColorShow() {
        return colorShow;
    }

    protected JPanel getPnlButtons() {
        return pnlButtons;
    }

    protected JPanel getPnlSldG() {
        return pnlSldG;
    }

    protected JPanel getPnlSldB() {
        return pnlSldB;
    }

    protected JPanel getPnlSldAlpha() {
        return pnlSldAlpha;
    }

    protected JPanel getPnlSldR() {
        return pnlSldR;
    }

    protected JButton getBtnBackground() {
        return btnBackground;
    }

    protected JButton getBtnText() {
        return btnText;
    }

    protected JButton getBtnPanels() {
        return btnPanels;
    }

    protected JButton getBtnButtonsText() {
        return btnButtonsText;
    }

    protected JButton getBtnSideList() {
        return btnSideList;
    }

    protected JButton getBtnButtonLabels() {
        return btnButtonLabels;
    }

    protected JButton getBtnButtonContours() {
        return btnButtonContours;
    }

    protected JButton getBtnSideListForeground() {
        return btnSideListForeground;
    }

    protected JButton getBtnForeground() {
        return btnForeground;
    }

    protected JLabel getLabel() {
        return label;
    }

    protected JSlider getSldG() {
        return sldG;
    }

    protected JSlider getSldB() {
        return sldB;
    }

    protected JSlider getSldAlpha() {
        return sldAlpha;
    }

    protected JSlider getSldR() {
        return sldR;
    }
}

This is the wrapper (just for readability):

import java.awt.Color;

import javax.swing.JComponent;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class ThemeWrapper {

    private Theme theme;
    private ThemeBuilder builder;
    private int r, g, b, a;

    public ThemeWrapper(Theme theme) {
        this.builder = new ThemeBuilder();
        this.builder.setVisible(true);
        this.theme = new Theme();
        this.r = builder.getSldR().getValue();
        this.g = builder.getSldG().getValue();
        this.b = builder.getSldB().getValue();
        this.a = builder.getSldAlpha().getValue();
        initializeBehaviors();
    }

    public void initializeBehaviors(){

        builder.getSldR().addChangeListener(new ChangeListener() {

            @Override
            public void stateChanged(ChangeEvent e) {

                if(e.getSource() == builder.getSldR()){
                    changeColor();
                }
            }
        });

        builder.getSldG().addChangeListener(new ChangeListener() {

            @Override
            public void stateChanged(ChangeEvent e) {

                if(e.getSource() == builder.getSldG()){
                    changeColor();
                }
            }
        });

        builder.getSldB().addChangeListener(new ChangeListener() {

            @Override
            public void stateChanged(ChangeEvent e) {

                if(e.getSource() == builder.getSldB()){
                    changeColor();
                }
            }
        });

        builder.getSldAlpha().addChangeListener(new ChangeListener() {

            @Override
            public void stateChanged(ChangeEvent e) {

                if(e.getSource() == builder.getSldAlpha()){
                    changeColor();
                }
            }
        });
    }

    private void changeColor(){
        r = builder.getSldR().getValue();
        g = builder.getSldG().getValue();
        b = builder.getSldB().getValue();
        a = builder.getSldAlpha().getValue();
        applyColor(builder.getColorShow());
    }

    private void applyColor(JComponent component){
        component.setBackground(new Color(r, g, b, a));
        component.repaint();
    }


    public void disposeFrames(){
        builder.setVisible(false);
        builder.dispose();
    }


    public Theme getTheme() {
        return theme;
    }
}

Answer 1

No I just figured it out, it's because you have to repaint the frame!

private void changeColor(){
    r = builder.getSldR().getValue();
    g = builder.getSldG().getValue();
    b = builder.getSldB().getValue();
    a = builder.getSldAlpha().getValue();
    applyColor(builder.getColorShow());
    builder.repaint();
}

Answer 2

component.setBackground(new Color(r, g, b, a));

Swing doesn't paint components with transparent backgrounds correctly.

You need to make sure the background is painted to remove painting artifacts. Check out Backgrounds With Transparency for more information and solutions.

Also:

1. Swing components are double buffered by default so there is no need to use setDoubleBuffered(true).

2. All components are painted when the frame is made visible so there is no need to invoke repaint() on individual components.