java - 如何让我的彩色图标显示在我的 GUI 上？

Question

我正在尝试创建一个 GUI，我可以在其中创建自定义颜色。我有一个功能可以让用户在提交颜色之前预览颜色。我根本无法显示图标。实际问题出在我的 ColorFrame 类中。颜色 Icon(a JLabel, color) 在 actionperformed() 方法中创建。

创建图标的代码(ButtonListener 类):

import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.Label;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BoxLayout;
import javax.swing.Icon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;


public class ColorFrame extends JFrame implements ActionListener {

private JPanel colorPanel;
private JPanel labelPanel;
private JPanel buttonPanel;

private JLabel labelRed;
private JLabel labelGreen;
private JLabel labelBlue;
private JLabel color;

private JTextField redField;
private JTextField greenField;
private JTextField blueField;

private JButton preview;
private JButton submit;


private int redInt;
private int blueInt;
private int greenInt;


private int width = 30;
private int height = 30;

public ColorFrame(int x, int y)
{
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //closes all frames for some reason
    this.pack();
    this.setLocation(x, y);

    buttonPanel = new JPanel();
    this.getContentPane().add(buttonPanel,BorderLayout.SOUTH);
    preview = new JButton("Preview Color");
    preview.addActionListener(new ButtonListener());
    buttonPanel.add(preview);
    createColorPanel();
    createLabelPanel();

    this.setVisible(true);

}

class ButtonListener implements ActionListener{

    @Override
    public void actionPerformed(ActionEvent arg0) {
        //in the gui, there are three jtextfieilds that represent color values. the first is red, the second is green, and the last is blue.
        redInt = Integer.parseInt(redField.getText());
        greenInt = Integer.parseInt(greenField.getText());
        blueInt = Integer.parseInt(blueField.getText());

        color = new JLabel(new ColorIcon(redInt,greenInt,blueInt));
        buttonPanel.add(color,BorderLayout.SOUTH);
        print(redInt,greenInt, blueInt);

    }

}


private void createColorPanel()
{
    colorPanel = new JPanel(new GridBagLayout());

    GridBagConstraints c = new GridBagConstraints();

    //creates the three textfields to input rgb values.
    //the first is r, second, b third g
    redField = new JTextField(2);
    c.fill = GridBagConstraints.VERTICAL;
    c.weightx = 0.5;
    c.gridx = 1;
    c.gridy = 0;
    c.insets = new Insets(10,0,0,10);
    colorPanel.add(redField,c);

    greenField = new JTextField(2);
    c.fill = GridBagConstraints.VERTICAL;
    c.weightx = 0.0;
    c.gridx = 1;
    c.gridy = 1;
    colorPanel.add(greenField,c);

    blueField = new JTextField(2);
    c.fill = GridBagConstraints.VERTICAL;
    c.weightx = 0.5;
    c.gridx = 1;
    c.gridy = 2;
    colorPanel.add(blueField,c);

    redField.addActionListener(this);
    greenField.addActionListener(this);
    blueField.addActionListener(this);



    this.add(colorPanel, BorderLayout.EAST);
}


public void actionPerformed(ActionEvent arg0) {
    redInt = Integer.parseInt(redField.getText());
    greenInt = Integer.parseInt(greenField.getText());
    blueInt = Integer.parseInt(blueField.getText());

    // creates the color icon. It works sometimes, but not every time.
    color = new JLabel(new ColorIcon(redInt,greenInt,blueInt));
    buttonPanel.add(color);
    print(redInt,greenInt, blueInt);

}


private void print(int a, int b, int c)
{
    // just to see if the actionperformed() method works.
    System.out.println(a);
    System.out.println(b);
    System.out.println(c);
}


public Dimension getPreferredSize() {
    return new Dimension(300,300);
}


public static void main(String[] args)
{
    ColorFrame frame = new ColorFrame(200,200); 
}


}

颜色图标类:

import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Rectangle2D;

import javax.swing.Icon;


public class ColorIcon implements Icon{



private final int size = 30;
private int red;
private int green;
private int blue;



public ColorIcon(int r, int g, int b)
{
    this.red = r;
    this.green = g;
    this.blue = b;
}


@Override
public int getIconHeight() {
    // TODO Auto-generated method stub
    return size;
}

@Override
public int getIconWidth() {
    // TODO Auto-generated method stub
    return size;
}

@Override
public void paintIcon(Component c, Graphics g, int x, int y) {
    // TODO Auto-generated method stub

    Graphics2D g2 = (Graphics2D) g;
    Rectangle2D.Double square = new Rectangle2D.Double(50, 50, size, size);
    g2.setColor(new Color(red,green,blue));
    g2.fill(square);
}

}

Answer 1

有多种可能的方法可以处理此问题。一种是创建一个面板，您可以在其中设置颜色并绘制整个面板。有点像

private class ColorPanel extends JPanel {
    private Color color = Color.BLUE;

    public void setColor(Color color) {
        this.color = color;
        repaint();
    }

    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.setColor(color);
        g.fillRect(0, 0, getWidth(), getHeight());
    }

    public Dimension getPreferredSize() {
        return new Dimension(150, 150);
    }
}

您可以只设置颜色。我注意到的另一件事是您正在尝试将新标签添加到按钮面板，但按钮面板位于框架的南边。我认为您希望标签位于框架的中央。因此，您需要将新标签单独添加到 CENTER，而不是按钮面板。

这是您的代码的重构。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class ColorFrame extends JFrame implements ActionListener {

    private JPanel colorPanel;
    private JPanel buttonPanel;

    private JLabel color;

    private JTextField redField;
    private JTextField greenField;
    private JTextField blueField;

    private JButton preview;

    private int redInt;
    private int blueInt;
    private int greenInt;

    private ColorPanel cPanel = new ColorPanel();

    public ColorFrame(int x, int y) {
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        buttonPanel = new JPanel();
        JPanel preferredSizeWrapper = new JPanel(new GridBagLayout());
        preferredSizeWrapper.add(cPanel);
        this.getContentPane().add(buttonPanel, BorderLayout.SOUTH);
        preview = new JButton("Preview Color");
        preview.addActionListener(new ButtonListener());
        buttonPanel.add(preview);
        createColorPanel();
        this.add(preferredSizeWrapper);
        this.pack();
        this.setLocation(x, y);
        this.setVisible(true);

    }

    class ButtonListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            // in the gui, there are three jtextfieilds that represent color
            // values. the first is red, the second is green, and the last is
            // blue.
            redInt = Integer.parseInt(redField.getText());
            greenInt = Integer.parseInt(greenField.getText());
            blueInt = Integer.parseInt(blueField.getText());
            // new ColorIcon(redInt, greenInt, blueInt)
            cPanel.setColor(new Color(redInt, greenInt, blueInt));
        }
    }

    private class ColorPanel extends JPanel {
        private Color color = Color.BLUE;

        public void setColor(Color color) {
            this.color = color;
            repaint();
        }

        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.setColor(color);
            g.fillRect(0, 0, getWidth(), getHeight());
        }

        public Dimension getPreferredSize() {
            return new Dimension(150, 150);
        }
    }

    private void createColorPanel() {
        colorPanel = new JPanel(new GridBagLayout());

        GridBagConstraints c = new GridBagConstraints();

        // creates the three textfields to input rgb values.
        // the first is r, second, b third g
        redField = new JTextField(2);
        c.fill = GridBagConstraints.VERTICAL;
        c.weightx = 0.5;
        c.gridx = 1;
        c.gridy = 0;
        c.insets = new Insets(10, 0, 0, 10);
        colorPanel.add(redField, c);

        greenField = new JTextField(2);
        c.fill = GridBagConstraints.VERTICAL;
        c.weightx = 0.0;
        c.gridx = 1;
        c.gridy = 1;
        colorPanel.add(greenField, c);

        blueField = new JTextField(2);
        c.fill = GridBagConstraints.VERTICAL;
        c.weightx = 0.5;
        c.gridx = 1;
        c.gridy = 2;
        colorPanel.add(blueField, c);

        redField.addActionListener(this);
        greenField.addActionListener(this);
        blueField.addActionListener(this);

        this.add(colorPanel, BorderLayout.EAST);
    }

    public void actionPerformed(ActionEvent arg0) {
        redInt = Integer.parseInt(redField.getText());
        greenInt = Integer.parseInt(greenField.getText());
        blueInt = Integer.parseInt(blueField.getText());

        colorPanel.add(color);

    }

    public Dimension getPreferredSize() {
        return new Dimension(300, 300);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                ColorFrame frame = new ColorFrame(200, 200);
            }
        });
    }
}

---

另一种选择是只使用常规的 JPanel

private JPanel createCPanel() {
    return new JPanel() {
        {
            setBackground(Color.BLUE);
        }
        @Override
        public Dimension getPreferredSize() {
            return new Dimension(150, 150);
        }
    };
}

然后在面板上调用 setBackground(Color)。不过，您还需要牢记上述更改。