loginframe.java

java编写的桌面考试系统.含所有源码.

package exam.gui;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;

import exam.dao.StudentFromCfg;
import exam.model.Student;

/**
 * 登录界面
 * 
 * @author 刘东
 * 
 */
public class LoginFrame implements ActionListener {
	private JFrame frame;
	private JButton login, cancel;
	private JTextField id;
	private JPasswordField pass;
	private JLabel titleL, idL, passL;
	private JPanel ps, pc, pn, pc1, pc2;

	public LoginFrame() {
		frame = new JFrame("考生登陆");
		login = new JButton("登陆");
		cancel = new JButton("取消");
		id = new JTextField(15);
		pass = new JPasswordField(15);
		titleL = new JLabel("考生登陆");
		idL = new JLabel("学号:");
		passL = new JLabel("密码:");
		pn = new JPanel();
		pc = new JPanel();
		ps = new JPanel();
		pc1 = new JPanel();
		pc2 = new JPanel();

		init();
	}

	private void init() {
		pn.add(titleL);

		pc1.add(idL);
		pc1.add(id);
		pc2.add(passL);
		pc2.add(pass);
		pass.addActionListener(this);

		pc.setLayout(new GridLayout(2, 1));
		pc.add(pc1);
		pc.add(pc2);

		ps.add(login);
		login.addActionListener(this);
		ps.add(cancel);
		cancel.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				frame.dispose();
			}
		});

		frame.add(pn, BorderLayout.NORTH);
		frame.add(pc, BorderLayout.CENTER);
		frame.add(ps, BorderLayout.SOUTH);

		frame.setSize(240, 180);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
		frame.setResizable(false);

		setThisLocation();
	}

	public void actionPerformed(ActionEvent arg0) {
		StudentFromCfg sfc = new StudentFromCfg();
		String inputId = id.getText().trim();
		String inputPassword = String.valueOf(pass.getPassword());
		if (inputId.equals("")) {
			JOptionPane.showMessageDialog(frame, "学号不能为空！", "操作提示",
					JOptionPane.WARNING_MESSAGE);
		} else if (inputPassword.equals("")) {
			JOptionPane.showMessageDialog(frame, "密码不能为空！", "操作提示",
					JOptionPane.WARNING_MESSAGE);
		} else if (isDigit(inputId)) {
			Student s = sfc
					.getStudent(Integer.parseInt(inputId), inputPassword);
			if (s == null) {
				JOptionPane.showMessageDialog(frame, "学号或密码错误！", "操作提示",
						JOptionPane.WARNING_MESSAGE);
				int selection = 0;
				if (selection == JOptionPane.OK_OPTION) {
					pass.setText("");
				}
			} else {
				frame.dispose();
				new SelectSubjectFrame(s);
			}
		} else {
			JOptionPane.showMessageDialog(frame, "学号格式错误！", "操作提示",
					JOptionPane.WARNING_MESSAGE);
		}
	}

	private boolean isDigit(String s) {
		char[] c = s.toCharArray();
		for (int i = 0; i < c.length; i++) {
			if (Character.isDigit(c[i]))
				continue;
			else
				return false;
		}
		return true;
	}

	private void setThisLocation() {
		Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
		Dimension frameSize = frame.getSize();
		if (frameSize.height > screenSize.height) {
			frameSize.height = screenSize.height;
		}
		if (frameSize.width > screenSize.width) {
			frameSize.width = screenSize.width;
		}
		frame.setLocation((screenSize.width - frameSize.width) / 2,
				(screenSize.height - frameSize.height) / 2);
		frame.setVisible(true);
	}
}