java - 如何制作圆角矩形 JTextField？

Question

我想制作一个圆角矩形 JTextField。我写了一个 AbstractBorder 的子类来实现它。但是我遇到了一些问题。我的要求是:

我得到的是:

我的代码是:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.AbstractBorder;
import javax.swing.border.EmptyBorder;


public class JTextFieldTest {
    JTextField textField;
    boolean activate = false;

    public void createUI(){
        JFrame frame = new JFrame("Test JTextField");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setResizable(true);

        MainPanel mainPanel = new MainPanel();
        frame.add(mainPanel,BorderLayout.CENTER);

        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        JTextFieldTest jTextFieldTest = new JTextFieldTest();
        jTextFieldTest.createUI();
    }

    @SuppressWarnings("serial")
    class MainPanel extends JPanel{
        public MainPanel(){

            textField = new JTextField("Please input:");
            Font fieldFont = new Font("Arial", Font.PLAIN, 20);
            textField.setFont(fieldFont);
            textField.setBackground(Color.white);
            textField.setForeground(Color.gray.brighter());

            textField.setColumns(30);
            textField.setBorder(BorderFactory.createCompoundBorder(new CustomeBorder(), 
new EmptyBorder(new Insets(10, 20, 10, 20))));
            textField.addActionListener(new FieldListener());
            textField.addMouseListener(new FieldMouseListener());

            add(textField,BorderLayout.CENTER);
            setBackground(Color.blue);
            setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        }
    }

    @SuppressWarnings("serial")
    class CustomeBorder extends AbstractBorder{
        @Override
        public void paintBorder(Component c, Graphics g, int x, int y,
                int width, int height) {
            // TODO Auto-generated method stub
            super.paintBorder(c, g, x, y, width, height);
            g.setColor(Color.black);
            g.drawRoundRect(x, y, width, height, 20, 20);
        }

    }

    class FieldListener implements ActionListener{

        @Override
        public void actionPerformed(ActionEvent e) {
            // TODO Auto-generated method stub
            System.out.println(textField.getText());
        }

    }

    class FieldMouseListener implements MouseListener{
        @Override
        public void mouseClicked(MouseEvent e) {
            // TODO Auto-generated method stub
            if(activate == false){
                textField.setText("");
            }
            activate = true;
            textField.setForeground(Color.black);


        }

        @Override
        public void mousePressed(MouseEvent e) {
            // TODO Auto-generated method stub

        }

        @Override
        public void mouseReleased(MouseEvent e) {
            // TODO Auto-generated method stub

        }

        @Override
        public void mouseEntered(MouseEvent e) {
            // TODO Auto-generated method stub

        }

        @Override
        public void mouseExited(MouseEvent e) {
            // TODO Auto-generated method stub

        }
    }
}

我可以通过使用得到另一种效果

textField.setOpaque(false);

g.setColor(Color.white); g.drawRoundRect(x, y, width - 1, height - 1, 20, 20);

另一个作用是:

总而言之，我该怎么做才能实现我的需求？

@Arijit，这是你的解决方案在我的电脑上运行时的效果。

Answer 1

使用 TextBubbleBorder。

import java.awt.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.border.AbstractBorder;

class TextBubbleBorder extends AbstractBorder {

    private Color color;
    private int thickness = 4;
    private int radii = 8;
    private int pointerSize = 7;
    private Insets insets = null;
    private BasicStroke stroke = null;
    private int strokePad;
    private int pointerPad = 4;
    RenderingHints hints;

    TextBubbleBorder(
        Color color) {
            this(color, 4, 8, 7);
    }

    TextBubbleBorder(
        Color color, int thickness, int radii, int pointerSize) {
            this.thickness = thickness;
            this.radii = radii;
            this.pointerSize = pointerSize;
        this.color = color;

        stroke = new BasicStroke(thickness);
        strokePad = thickness/2;

        hints = new RenderingHints(
            RenderingHints.KEY_ANTIALIASING,
            RenderingHints.VALUE_ANTIALIAS_ON);

        int pad = radii + strokePad;
        int bottomPad = pad + pointerSize + strokePad;
        insets = new Insets(pad,pad,bottomPad,pad);
    }

    @Override
    public Insets getBorderInsets(Component c) {
        return insets;
    }

    @Override
    public Insets getBorderInsets(Component c, Insets insets) {
        return getBorderInsets(c);
    }

    @Override
    public void paintBorder(
        Component c,
        Graphics g,
        int x, int y,
        int width, int height) {

        Graphics2D g2 = (Graphics2D)g;

        int bottomLineY = height-thickness-pointerSize;

        RoundRectangle2D.Double bubble = new RoundRectangle2D.Double(
            0+strokePad,
            0+strokePad,
            width-thickness,
            bottomLineY,
            radii,
            radii
            );

        Polygon pointer = new Polygon();

        // left point
        pointer.addPoint(
            strokePad+radii+pointerPad,
            bottomLineY);
        // right point
        pointer.addPoint(
            strokePad+radii+pointerPad+pointerSize,
            bottomLineY);
        // bottom point
        pointer.addPoint(
            strokePad+radii+pointerPad+(pointerSize/2),
            height-strokePad);

        Area area = new Area(bubble);
        area.add(new Area(pointer));

        g2.setRenderingHints(hints);

        Area spareSpace = new Area(new Rectangle(0,0,width,height));
        spareSpace.subtract(area);
        g2.setClip(spareSpace);
        g2.clearRect(0,0,width,height);
        g2.setClip(null);

        g2.setColor(color);
        g2.setStroke(stroke);
        g2.draw(area);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                JTextField o = new JTextField(
                    "The quick brown fox jumps over the lazy dog!");

                o.setBorder(new TextBubbleBorder(Color.MAGENTA.darker(),2,4,0));
                JOptionPane.showMessageDialog(null, o);
            }
        });
    }
}