Question

我尝试在5秒后更改jtextfield边框。但不起作用。我的代码：

    // Here vaildate a field and set border to red
    if (ApplicationNameField.getText().equals("")) {
        Border newBorder = BorderFactory.createLineBorder(Color.RED, 1);
        ApplicationNameField.setBorder(newBorder);
        ErrorCode.setText("Error field cant be empty");
    }
    if (ApplicationHostField.getText().equals("")) {
        Border newBorder = BorderFactory.createLineBorder(Color.RED, 1);
        ApplicationHostField.setBorder(newBorder);
        ErrorCode.setText("Error field cant be empty");
    }

   // here i would change border to start normal color (color black)
   try {
        TimeUnit.SECONDS.sleep(5);
        Border newBorder = BorderFactory.createLineBorder(Color.BLACK, 1);
        ApplicationNameField.setBorder(newBorder);
        Border newBorder2 = BorderFactory.createLineBorder(Color.BLACK, 1);
        ApplicationHostField.setBorder(newBorder2);

    } catch (InterruptedException ex) {
        System.out.print(ex.getMessage());
    }

在此代码之后，我的JTextFields边框是黑色的，并且没有用红色着色。

我也尝试过：

     Thread.sleep(5000);

但效果是一样的。有人可以帮忙吗？

Answer 1

您需要使用javax.swing.Timer在5秒后触发所需的操作。 Thread.wait（或任何其他类型的等待）没有按预期工作，因为在线程返回主事件循环之前不会绘制任何内容。

Answer 2

同意@ammoQ。请提供一个使用javax.swing.Timer的示例。

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.Timer;
import javax.swing.border.AbstractBorder;
import javax.swing.border.EmptyBorder;
import javax.swing.border.LineBorder;


public class TimerTest implements ActionListener{
    JTextField textField;

    public void createUI(){
        JFrame frame = new JFrame("Timer Test");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setResizable(false);

        MainPanel mainPanel = new MainPanel();
        mainPanel.setBorder(BorderFactory.createEmptyBorder(5, 10, 5, 10));
        frame.add(mainPanel,BorderLayout.CENTER);

        frame.pack();
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);

        Timer timer = new Timer(5 * 1000, this);
        timer.start();
    }

    public static void main(String[] args) {
        TimerTest timerTest = new TimerTest();
        timerTest.createUI();
    }



    @SuppressWarnings("serial")
    class MainPanel extends JPanel{
        public MainPanel(){
            textField = new JTextField();
            textField.setColumns(30);
            textField.setBorder(BorderFactory.createCompoundBorder(
                    new LineBorder(Color.red, 3),
                    new EmptyBorder(new Insets(15, 25, 15, 25))));


            add(textField,BorderLayout.CENTER);
            setBackground(new Color(211,211,211));
            setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
        }
    }



    @Override
    public void actionPerformed(ActionEvent e) {
        // TODO Auto-generated method stub
        textField.setBorder(BorderFactory.createCompoundBorder(
                new LineBorder(Color.black, 3),
                new EmptyBorder(new Insets(15, 25, 15, 25))));
    }
}

Answer 3

您可以使用SwingWorker执行此操作。请参阅下面的运行示例。

import java.awt.Color;
import java.awt.EventQueue;

import javax.swing.BorderFactory;
import javax.swing.GroupLayout;
import javax.swing.GroupLayout.Alignment;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingWorker;
import javax.swing.border.EmptyBorder;

public class JTextFieldTest extends JFrame {

    private JPanel contentPane;
    private JTextField textField;

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

    /**
     * Create the frame.
     */
    public JTextFieldTest() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 298, 220);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);

        textField = new JTextField();
        textField.setColumns(10);
        textField.setBorder(BorderFactory.createLineBorder(Color.RED));
        SwingWorker<Void, Void> worker = new SwingWorker<Void, Void>() {
            @Override
            protected Void doInBackground() throws Exception {
                // Simulate doing something useful.
                Thread.sleep(5000);
                textField.setBorder(BorderFactory.createLineBorder(Color.BLACK));
                return null;
            }
        };

        worker.execute();
        GroupLayout gl_contentPane = new GroupLayout(contentPane);
        gl_contentPane.setHorizontalGroup(gl_contentPane.createParallelGroup(
                Alignment.LEADING).addGroup(
                gl_contentPane
                        .createSequentialGroup()
                        .addGap(87)
                        .addComponent(textField, GroupLayout.PREFERRED_SIZE,
                                GroupLayout.DEFAULT_SIZE,
                                GroupLayout.PREFERRED_SIZE)
                        .addContainerGap(99, Short.MAX_VALUE)));
        gl_contentPane.setVerticalGroup(gl_contentPane.createParallelGroup(
                Alignment.LEADING).addGroup(
                gl_contentPane
                        .createSequentialGroup()
                        .addGap(70)
                        .addComponent(textField, GroupLayout.PREFERRED_SIZE,
                                GroupLayout.DEFAULT_SIZE,
                                GroupLayout.PREFERRED_SIZE)
                        .addContainerGap(81, Short.MAX_VALUE)));
        contentPane.setLayout(gl_contentPane);
    }

}

如何在5秒后更改jtextfield边框？

3 个答案: