隐形GUI？(Java)(Swing)

Question

我正在研究这个程序,使用swing.每次导出程序并运行它时,我都会尝试设置的GUI.JFrame可以,但不是内部组件.提前谢谢〜艾利斯

码:

import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

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

public class Login {
    public static void login_Interface(){

        //Start GUI style//
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
        } catch (ClassNotFoundException e1) {
            e1.printStackTrace();
        } catch (InstantiationException e1) {
            e1.printStackTrace();
        } catch (IllegalAccessException e1) {
            e1.printStackTrace();
        } catch (UnsupportedLookAndFeelException e1) {
            e1.printStackTrace();
        }
        //      End     //

        JFrame login_Frame = new JFrame("Login - LetsMeet");
        login_Frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        login_Frame.setSize(750, 650);
        login_Frame.setResizable(true);

        JPanel panel_Title = new JPanel();                            //PANEL Title
        panel_Title.setBounds(0, 0, 750, 150);
        panel_Title.setLayout(null);
        Image logo = null;
        try {
            logo = ImageIO.read(new File("Data/images/logo_letsmeet.png"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        Graphics2D logo_out = ((BufferedImage) logo).createGraphics();
        panel_Title.paint(logo_out);

        JPanel login_Panel = new JPanel();                            //LOGIN Panel
        login_Panel.setBounds(0, 150, 350, 150);
        login_Panel.setLayout(null);
        JTextField username_login = new JTextField("Username");
        username_login.setBounds(100, 50, 100, 25);
        JPasswordField password_login = new JPasswordField();
        password_login.setBounds(200, 50, 100, 25);
        JButton login_go = new JButton("Login");
        login_go.setBounds(200, 50, 100, 25);
        login_Panel.add(password_login);
        login_Panel.add(username_login);


        JPanel panel_Divider = new JPanel();                          //PANEL Divider
        login_Panel.setBounds(350, 150, 50, 150);
        panel_Divider.setSize(50, 100);
        panel_Divider.setLayout(null);
        Image sep = null;
        try {
            sep = ImageIO.read(new File("Data/images/sep.png"));
        } catch (IOException e) {
            e.printStackTrace();
        }
        Graphics2D div = ((BufferedImage) sep).createGraphics();
        panel_Title.paint(div);

        JPanel register_Panel = new JPanel();                         //REGISTER Panel
        register_Panel.setBounds(400, 150, 350, 150);
        register_Panel.setLayout(null);

        login_Frame.add(panel_Title);
        login_Frame.add(login_Panel);
        login_Frame.add(panel_Divider);
        login_Frame.add(register_Panel);
        login_Frame.setVisible(true);
    }
}

错误:无

Answer 1

首先...

panel_Title.paint(logo_out); 这不是Swing中图形的工作方式......也不是Swing中图像的绘制方式

其次...

您应该使用布局管理器,它们将大大减少潜在问题并降低代码的复杂性.

第三

您的应用程序应该在Event Dispatching Thread的上下文中启动...

public static void main(String args[]) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            // Construct your UI here...
        }
    });
}

第四

正如Andrew也指出的那样(+1)......你的图像"看起来"是内部资源,不能通过File引用访问.您需要以不同方式加载这些(嵌入式)资源...

logo = ImageIO.read(Login.class.getResource("/Data/images/logo_letsmeet.png"));

你也忽略了这些资源的潜力,null这是一种非常危险的做法.

我建议你仔细阅读

• 如何使用图标
• 使用JFC/Swing创建GUI