Question

我又回到了另一个非常愚蠢的问题。我已经阅读了其他一些stackoverflow帖子，并尝试按照建议，但无济于事。我无法将JPanel背景更改为图像！我尝试将图像移动到我的c：\，所以不是那样。

请提前帮助和谢谢！

登录代码：

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.*;


public class login implements ActionListener{


    JTextField gusername;
    JTextField gpassword;
    static String username;
    static String password;

    void logini() throws IOException {

        JFrame window = new JFrame("Login");
        window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        window.setSize(300, 250);
        window.setResizable(false);
        window.setVisible(true);

        JPanel mainp = new JPanel(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();
        window.add(mainp);



        BufferedImage myPicture = ImageIO.read(new File("c:\bgd.png"));
        JLabel picLabel = new JLabel(new ImageIcon( myPicture ));
        mainp.add( picLabel );




        c.gridx = 0;
        c.gridy = 1;
        gusername = new JTextField();
        gusername.setText("Username");
        mainp.add(gusername, c);

        c.gridx = 0;
        c.gridy = 2;
        gpassword = new JTextField();
        gpassword.setText(" password ");
        mainp.add(gpassword, c);

        c.gridx = 0;
        c.gridy = 3;
        JButton login = new JButton("Login");
        mainp.add(login, c);

        login.addActionListener(this);
        login.setActionCommand("ok");
    }


    public void actionPerformed(ActionEvent e) {
        if (e.getActionCommand().equalsIgnoreCase("ok")){
            try {
                this.username = (gusername.getText());
                this.password = (gpassword.getText());
                System.out.println("0");

            }
            catch(NumberFormatException ex){
                System.out.println("ERROR: Could not preform function: 7424");

            }
        }
    }


}

错误：

Exception in thread "main" javax.imageio.IIOException: Can't read input file!
    at javax.imageio.ImageIO.read(Unknown Source)
    at login.logini(login.java:34)
    at Main.main(Main.java:10)

Answer 1

逃避路径中的反斜杠。

反斜杠是字符串中的特殊转义字符。 \b是一个特殊字符，而不是反斜杠和b。要获得反斜杠，您需要其中两个\\。

BufferedImage myPicture = ImageIO.read(new File("c:\\bgd.png"));

我建议使用File.separatorChar代替平台无关，但C:几乎不依赖于平台。

第一次设置JPanel / JFrame背景图片

1 个答案: