【GUI】-- 07 Icon & ImageIcon、JPanel & JScroll

GUI编程

03 Swing

3.3 Icon

1. 自定义Label的图标

package com.duo.lesson04;

import javax.swing.*;
import java.awt.*;

public class IconDemo extends JFrame implements Icon {

    private int width;
    private int height;

    public IconDemo() {}  //无参构造

    public IconDemo(int width, int height) {
        this.width = width;
        this.height = height;
    }

    public void init() {
        IconDemo iconDemo1 = new IconDemo(20, 20);
        //图标可以放在标签，按钮上
        JLabel jLabel = new JLabel("icon_1", iconDemo1, SwingConstants.CENTER);
        Container contentPane = getContentPane();
        contentPane.add(jLabel);

        setTitle("图标测试窗口");
        setSize(650, 500);
        setLocationRelativeTo(null);
        setVisible(true);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        new IconDemo().init();
    }

    @Override
    public void paintIcon(Component c, Graphics g, int x, int y) {
        g.fillOval(x, y, width, height);
    }

    @Override
    public int getIconWidth() {
        return width;
    }

    @Override
    public int getIconHeight() {
        return height;
    }
}
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运行结果：

2. 以图片作为Label的Icon：

package com.duo.lesson04;

import javax.swing.*;
import java.awt.*;
import java.net.URL;

public class ImageIconDemo extends JFrame{

    public ImageIconDemo() {
        //获取图片地址
        URL url = ImageIconDemo.class.getResource("通用头像.jpg");

        JLabel jLabel = new JLabel("ImageIcon");

        assert url != null;
        ImageIcon imageIcon = new ImageIcon(url);  //注意类名不要与内置类ImageIcon重名
        jLabel.setIcon(imageIcon);
        jLabel.setHorizontalAlignment(SwingConstants.CENTER);

        Container contentPane = getContentPane();
        contentPane.add(jLabel);

        setTitle("图片图标测试窗口");
        setSize(650, 500);
        setLocationRelativeTo(null);
        setVisible(true);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        new ImageIconDemo();
    }
}
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运行结果：

3.4 JPanel

1. JFrame下的面板JPanel：

package com.duo.lesson05;

import javax.swing.*;
import java.awt.*;

public class JPanelDemo extends JFrame {
    public JPanelDemo() {
        Container contentPane = getContentPane();
        contentPane.setLayout(new GridLayout(2, 1, 10, 10));  //hgap和vgap代表面板之间的间距

        JPanel jPanel1 = new JPanel(new GridLayout(1, 3));
        jPanel1.add(new JButton("One"));
        jPanel1.add(new JButton("One"));
        jPanel1.add(new JButton("One"));

        JPanel jPanel2 = new JPanel(new GridLayout(2, 1));
        jPanel2.add(new JButton("Two"));
        jPanel2.add(new JButton("Two"));

        JPanel jPanel3 = new JPanel(new GridLayout(3, 2));
        jPanel3.add(new JButton("Three"));
        jPanel3.add(new JButton("Three"));
        jPanel3.add(new JButton("Three"));
        jPanel3.add(new JButton("Three"));
        jPanel3.add(new JButton("Three"));
        jPanel3.add(new JButton("Three"));

        JPanel jPanel4 = new JPanel(new GridLayout(1, 2));
        jPanel4.add(new JButton("Four"));
        jPanel4.add(new JButton("Four"));

        contentPane.add(jPanel1);
        contentPane.add(jPanel2);
        contentPane.add(jPanel3);
        contentPane.add(jPanel4);

        setTitle("面板测试窗口");
        setSize(650, 500);
        setLocationRelativeTo(null);
        setVisible(true);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        new JPanelDemo();
    }
}
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运行结果：

2. JScroll

JScroll是带有滚轮可上下左右滑动的面板。

package com.duo.lesson05;

import javax.swing.*;
import java.awt.*;

public class JScrollDemo extends JFrame {
    public JScrollDemo() {
        Container contentPane = getContentPane();

        JTextArea jTextArea = new JTextArea("你好", 40, 100);
        //jTextArea.setText("你好");
        jTextArea.setFont(new Font("宋体", Font.PLAIN, 20));

        //Scroll
        JScrollPane jScrollPane = new JScrollPane(jTextArea);
        contentPane.add(jScrollPane);

        setVisible(true);
        setSize(650, 500);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    }

    public static void main(String[] args) {
        new JScrollDemo();
    }
}
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运行结果：

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