java - 带有图像的 GUI 窗口

Question

我正在创建一个 gui，顶部有一个图像，下面有一个按钮。每次单击该按钮时，图像都会发生变化能够更改图像 3 次并从第一次开始我遇到了一个问题，希望有人可以回答这是我的代码

import java.awt.*;
import java.awt.event.*;

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

import java.io.*;


public class GUIExample extends Frame implements WindowListener,ActionListener {
Button b;
JLabel Picture;
ImageIcon pic,dup;
private int numClicks = 0;
int k = 0;
Image[] img = new Image[3];
public static void main(String[] args) throws IOException {
    GUIExample myWindow = new GUIExample("GUIExample");
    myWindow.setSize(500,500);
    myWindow.setVisible(true);
}

public GUIExample(String title) throws IOException {
    super(title);
    img[0] = ImageIO.read(new File("Earth1.jpg"));
    img[1] = ImageIO.read(new File("Earth2.jpg"));
    img[2] = ImageIO.read(new File("Earth3.jpg"));

    setLayout(new FlowLayout());
    addWindowListener(this);
    b = new Button("Change Image");
    Image i = img[0].getScaledInstance(300, 300, java.awt.Image.SCALE_SMOOTH);
    pic = new ImageIcon(i);
    Picture = new JLabel(pic);
    add(Picture);
    add(b);
    b.addActionListener(this);
}


public void actionPerformed(ActionEvent e) {
    numClicks++;
    System.out.println("a");
    System.out.println(numClicks);
    paint1();
}

public void paint1()
{
    System.out.println("b");
    switch(numClicks){
    case 1 : k = 1;
    break;
    case 2 : k = 2;
    break;
    case 3 : k = 0;numClicks = 0;
    break;
    }
    System.out.println(k);
    Image t = img[k].getScaledInstance(300, 300, java.awt.Image.SCALE_SMOOTH);
    pic.setImage(t);
    Picture.setIcon(pic);
}

public void windowClosing(WindowEvent e) {
    dispose();
    System.exit(0);
}

public void windowOpened(WindowEvent e) {}
public void windowActivated(WindowEvent e) {}
public void windowIconified(WindowEvent e) {}
public void windowDeiconified(WindowEvent e) {}
public void windowDeactivated(WindowEvent e) {}
public void windowClosed(WindowEvent e) {}

}

这是我遇到的错误

Exception in thread "main" javax.imageio.IIOException: Can't read input file!
at javax.imageio.ImageIO.read(Unknown Source)
at gui.GUIExample.<init>(GUIExample.java:28)
at gui.GUIExample.main(GUIExample.java:21)

有没有一种更简单的方法可以在不使用 IO 的情况下将我的照片加载到此中，这对我来说是一个新概念。任何有关如何使其正确运行的其他建议将不胜感激。

谢谢

Answer 1

混合了两种 GUI 框架，

• AWT(框架、按钮)
• Swing(JLabel)

最好选择较新的 Swing 。

开始:

public class SlideShow extends JFrame {

public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {

        @Override
        public void run() {
            new SlideShow().setVisible(true);
        }});
}

字段:

private Image[] imgs;
private int currentImgIndex;
private JLabel imageComponent = new JLabel();
private Action nextAction = new AbstractAction() {
    {
        putValue(NAME, "Next");
    }

    @Override
    public void actionPerformed(ActionEvent arg0) {
        currentImgIndex = (currentImgIndex + 1) % imgs.length;
        imageComponent.setIcon(new ImageIcon(imgs[currentImgIndex]));
        imageComponent.repaint(50L);
    }
};

nextAction 是一个解耦的“操作”，您可以重复使用它，将其放在按钮上，同时放置在菜单栏中的菜单中。

构造函数构建所有:

public SlideShow() {

    String dir = "C:/.../media";
    try {
        imgs = new Image[3];
        imgs[0] = ImageIO.read(new File(dir + "/image2.png"));
        imgs[1] = ImageIO.read(new File(dir + "/image5.png"));
        imgs[2] = ImageIO.read(new File(dir + "/image12.png"));
    } catch (IOException e) {
        e.printStackTrace();
    }

    setTitle("Slide Show");
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setBounds(0, 0, 800, 600);

    add(imageComponent, BorderLayout.CENTER);

    JButton nextButton = new JButton(nextAction);
    nextButton.setPreferredSize(new Dimension(100, 30));
    add(nextButton, BorderLayout.SOUTH);

    imageComponent.setIcon(new ImageIcon(imgs[currentImgIndex]));        
}

默认情况下，这些 add(...) 引用的内容 Pane 位于边框布局中，就像您所做的那样。

就是这样。

AbstractAction 中的 { ... } 构造是一个初始化 block ，就像构造函数一样。