package th7;

import java.awt.BorderLayout;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JCheckBox;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

public class SimpleEx extends JFrame {

	private JPanel contentPane;
	private JTextField textField;
	private JTextField textField_1;
	private JTextField textField_2;

	/**
	 * Launch the application.
	 */
	public static void main(String[] args) {
		EventQueue.invokeLater(new Runnable() {
			public void run() {
				try {
					SimpleEx frame = new SimpleEx();
					frame.setVisible(true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

	/**
	 * Create the frame.
	 */
	public SimpleEx() {
		setTitle("PTB1");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setLocationRelativeTo(null);  // *** 
		setBounds(100, 100, 450, 300);
		contentPane = new JPanel();
		contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
		setContentPane(contentPane);
		contentPane.setLayout(null);

		textField = new JTextField();
		textField.setToolTipText("");
		textField.setBounds(182, 34, 42, 20);
		contentPane.add(textField);
		textField.setColumns(10);

		textField_1 = new JTextField();
		textField_1.setBounds(182, 65, 42, 20);
		contentPane.add(textField_1);
		textField_1.setColumns(10);

		textField_2 = new JTextField();
		textField_2.setEditable(false);
		textField_2.setBounds(182, 135, 109, 20);
		contentPane.add(textField_2);
		textField_2.setColumns(10);

		JLabel lblA = new JLabel("a =");
		lblA.setBounds(76, 36, 46, 14);
		contentPane.add(lblA);

		JLabel lblB = new JLabel("b = ");
		lblB.setBounds(76, 68, 46, 14);
		contentPane.add(lblB);

		JLabel lblC = new JLabel("K\u1EBFt qu\u1EA3:");
		lblC.setBounds(76, 138, 77, 14);
		contentPane.add(lblC);

		JButton btnTnh = new JButton("T\u00EDnh");
		btnTnh.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent arg0) {
				double a=0;
				try
				{
					a = Double.parseDouble(textField.getText());
				}catch(Exception e)
				{
					JOptionPane.showMessageDialog(null, "nhập a");
					return;
				}
				double b=0;
				try
				{
					b = Double.parseDouble(textField_1.getText());
				}catch(Exception e)
				{
					JOptionPane.showMessageDialog(null, "nhập b");
					return;
				}
				if(a==0)
				{
					JOptionPane.showMessageDialog(null, "Không thể chia cho 0");
				}
				else
				{
					textField_2.setText(-b/a+"");
				}

			}
		});
		btnTnh.setBounds(76, 104, 148, 23);
		contentPane.add(btnTnh);
	}
}