观察...

Question

好的，我刚刚习惯OOP，现在正在学习挥杆。我正在制作一个简单的应用程序，该应用程序是2x2网格，包含4张图像（X，O，正方形和三角形），然后单击任意一个将颜色的形状切换为蓝色。

尽管我无法切换到新图像，但我认为它与程序的基本功能有关。

介意吗？

JFrame类：

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.ImageIcon;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import java.io.File;
import java.io.IOException;
import javax.swing.JPanel;

public class Frame1 {

    public JFrame frame;

        Frame1 window = new Frame1();
        window.frame.setVisible(true);

    }

    public Frame1() {
        initialize();
    }

    private void initialize() {
        frame = new JFrame();
        frame.setBounds(100, 100, 900, 900);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        Squares x = new Squares("images\\black-X.png", "images\\blue-X.png", 0, 0, 450, 450, "x");
        Squares o = new Squares("images\\black-O.png", "images\\blue-O.png", 450, 0, 450, 450, "o");
        Squares sq = new Squares("images\\black-sq.png", "images\\blue-sq.png", 0, 425, 450, 450, "sq");
        Squares tri = new Squares("images\\black-tri.png", "images\\blue-tri.png", 450, 410, 450, 450, "tri");


        frame.getContentPane().add(x.getLabel());
        frame.getContentPane().add(o.getLabel());
        frame.getContentPane().add(sq.getLabel());
        frame.getContentPane().add(tri.getLabel());
    }


}

Mouselistener类别：

import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

public class clickListener implements MouseListener{

    Squares ob = new Squares();

    public clickListener(Squares newSquare) {
        ob = newSquare;
    }

    public void mouseClicked(MouseEvent e) {
        ob.changePic();
    }

}

然后是我为每个图像创建的对象类

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;

public class Squares {

    String pic1, pic2, name;
    int x, y, width, height;

    JPanel panel = new JPanel();
    JLabel label = new JLabel();

    public Squares() {
        ;
    }

    public Squares(String pic1, String pic2, int x, int y, int width, int height, String name) {
        this.pic1 = pic1;
        this.pic2 = pic2;
        this.x = x;
        this.y = y;
        this.width = width;
        this.height = height;
        this.name = name;

        BufferedImage myPic1 = null;

        try {
            myPic1 = ImageIO.read(new File(pic1));

        } catch (IOException ex) {System.out.println("error in image upload");}

        /*
        panel.setBounds(x, y, width, height);
        panel.add(new JLabel(new ImageIcon(myPic1)));   
        panel.addMouseListener(new clickListener(this));
        */

        label = new JLabel(new ImageIcon(myPic1));
        label.setBounds(x, y, width, height);
        label.addMouseListener(new clickListener(this));
    }

    public JLabel getLabel() {
        return label;
    }

    public String getName() {
        return this.name;
    }

    public void changePic() {
        JOptionPane.showMessageDialog(null, "change pic reached for " + this.name);
        BufferedImage myPic2 = null;
        try {myPic2 = ImageIO.read(new File(pic2));}
        catch(IOException ex) {System.out.println("error in image upload");}
        label = new JLabel(new ImageIcon(myPic2));
        label.setBounds(x, y, width, height);
        label.repaint();
        label.revalidate();
    }
}

我最初使用的是包含每个JLabel的JPanels，但为了简化起见，我将它们全部删除了。

是的，任何建议都值得赞赏。谢谢！

Answer 1

因此，您的changePic方法中存在“核心”问题

public void changePic() {
    JOptionPane.showMessageDialog(null, "change pic reached for " + this.name);
    BufferedImage myPic2 = null;
    try {
        myPic2 = ImageIO.read(new File(pic2));
    } catch (IOException ex) {
        System.out.println("error in image upload");
    }
    label = new JLabel(new ImageIcon(myPic2));
    label.setBounds(x, y, width, height);
    label.repaint();
    label.revalidate();
}

在此方法中，您创建了JLabel的新实例，但是它永远不会添加到屏幕上附加的任何容器中，因此它永远不会显示。

简单的解决方案是仅更改icon的现有实例的JLabel属性

public void changePic() {
    JOptionPane.showMessageDialog(null, "change pic reached for " + this.name);
    BufferedImage myPic2 = null;
    try {
        myPic2 = ImageIO.read(new File(pic2));
    } catch (IOException ex) {
        System.out.println("error in image upload");
    }
    label.setIcon(new ImageIcon(pic2));
}

观察...

在遍历代码的同时，我发现一些可以做得更好的事情。

（尽管是名称）Frame1的管理主机架实际上不是责任。通过不同的容器可以更好地管理核心功能，这可以使组件分离，并在长期错误的情况下使其更加灵活和可重复使用-您也无需在其他职责中将框架管理的复杂性包括在内。
您应避免使用null版式。一种更简单的解决方案是使用GridLayout，因为您提供的实现存在布局问题
Squares不需要知道父容器想要的位置或大小-这并不是父容器直接做出的真正决定。相反，Squares应该向父容器提供大小调整提示，以便可以就如何布局所有子组件做出更好的决策。 JLabel本身可以提供此信息。
可以说Squares应该从JLabel扩展-这纯粹是简单性之一。 JLabel是显示图像的理想之地，因此这是一个不错的选择，但是在其周围包装一个类只会使它的管理更加麻烦，在这种情况下，几乎没有增加任何价值。对于继承而言，要达成协议，但是在这种情况下，我不确定它将增加更多的价值
ClickListener不需要创建Squares的实例，它只是构造函数要求任何调用者始终将Squares的实例传递给它
由于其核心功能，如果无法加载其中任何一个图像，Squares应该会失败，这将使诊断这些问题变得更加容易，而不是让程序继续以“中断”状态运行状态

恕我直言

示例

import java.awt.EventQueue;
import java.awt.GridLayout;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class Game {

    public static void main(String[] args) {
        new Game();
    }

    public Game() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    try {
                        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                    } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                        ex.printStackTrace();
                    }

                    JFrame frame = new JFrame("Testing");
                    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                    frame.add(new GamePane());
                    frame.pack();
                    frame.setLocationRelativeTo(null);
                    frame.setVisible(true);
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            }
        });
    }

    public class GamePane extends JPanel {

        public GamePane() throws IOException {
            initialize();

        }

        private void initialize() throws IOException {
            Square x = new Square("images\\black-X.png", "images\\blue-X.png", "x");
            Square o = new Square("images\\black-O.png", "images\\blue-O.png", "o");
            Square sq = new Square("images\\black-sq.png", "images\\blue-sq.png", "sq");
            Square tri = new Square("images\\black-tri.png", "images\\blue-tri.png", "tri");

            setLayout(new GridLayout(2, 2));

            add(x);
            add(o);
            add(sq);
            add(tri);
        }

    }

    public class ClickListener extends MouseAdapter {

        private Square ob;

        public ClickListener(Square newSquare) {
            ob = newSquare;
        }

        public void mouseClicked(MouseEvent e) {
            ob.changePic();
        }

    }

    public class Square extends JLabel {

        String name;
        private BufferedImage myPic1, myPic2;

        public Square(String pic1, String pic2, String name) throws IOException {
            this.name = name;

            myPic1 = ImageIO.read(new File(pic1));
            myPic2 = ImageIO.read(new File(pic2));

            setIcon(new ImageIcon(myPic1));
            addMouseListener(new ClickListener(this));
        }

        public String getName() {
            return this.name;
        }

        public void changePic() {
            setIcon(new ImageIcon(myPic2));
        }
    }
}

在Swing中的JLabel中更新图像图标？使用revalidate（）和repaint（）但不起作用

1 个答案:

观察...

示例