代码之家 › 专栏 › 技术社区 › Jennifer Oclaray Hast

我试图在每次按下按钮时更改JPanel的背景色

actionlistener jbutton jframe swing java

Jennifer Oclaray Hast · 技术社区 · 7 年前

import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class TimeFrame extends JFrame {
        private static final int FRAME_WIDTH = 250;
        private static final int FRAME_HEIGHT = 200;
        private JButton CurrentTime;
        private JLabel CurrentTimeLabel;
        private JTextField CurrentTimeField;
        private int click;
        private JTextField clicktest;

        public TimeFrame() {
            CurrentTimeLabel = new JLabel("The Current Time is: ");

            createTextField();
            createButton();
            createPanel();

            setSize(FRAME_WIDTH, FRAME_HEIGHT);
            setSize(250, 200);
            initialize();


        }
        private void initialize()
        {
        click = 0;
        }

        private void createTextField()
        {
           final int FIELD_WIDTH = 10;
           CurrentTimeField = new JTextField(FIELD_WIDTH);
           Date now = new Date();
           DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
           CurrentTimeField.setText("" + dateFormat.format(now));

           clicktest = new JTextField(FIELD_WIDTH);
           clicktest.setText(" " + click);

        }
        private void createButton()
        {
            CurrentTime = new JButton("Display Current Time");

            ActionListener listener = new AddCurrentTimeListener();
            CurrentTime.addActionListener(listener);

        }
        private void createPanel()
        {
           JPanel panel = new JPanel();
           //panel.addActionListener(backgroundListener);
           panel.add(CurrentTimeLabel);
           panel.add(CurrentTimeField);
           panel.add(CurrentTime);
           panel.add(clicktest);
           //int click = 0;

           if (click == 0){
                panel.setBackground(Color.ORANGE);
            } 
           else if (click == 1) {
                panel.setBackground(Color.YELLOW);
            } 
           else if (click == 2) {
                panel.setBackground(Color.BLUE);
            } 
           else if (click == 3) {
                panel.setBackground(Color.GREEN);
            } 
           else if (click == 4) {
                panel.setBackground(Color.PINK);
            }

           add(panel);

        }

        class AddCurrentTimeListener implements ActionListener
        {
           public void actionPerformed(ActionEvent event){

               new java.util.Date();
               Date now = new Date();
               DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
               CurrentTimeField.setText("" + dateFormat.format(now));getClass();                                   
               if (click < 4){
                   click++;
               } else  {
                   click = click - 4;}

               clicktest.setText("" + click);getClass();

               /**
               if (click == 0){
                    panel.setBackground(Color.ORANGE);
                } 
               else if (click == 1) {
                    panel.setBackground(Color.YELLOW);
                } 
               else if (click == 2) {
                    panel.setBackground(Color.BLUE);
                } 
               else if (click == 3) {
                    panel.setBackground(Color.GREEN);
                } 
               else if (click == 4) {
                    panel.setBackground(Color.PINK);
                }
               */

               repaint();
               }


            }

}

1 回复 | 直到 7 年前

MadProgrammer 7 年前

通过添加 JPanel 对于帧,您正在有效地阻止帧 contentPane ActionListener ,您正在尝试设置帧本身的背景色。

现在,这不起作用,因为框架是由许多重叠的组件组成的。

内容窗格

相反,您应该更改的背景。

好的,但这让我们回到第一个问题(即 面板 监听器 内容窗格 ,你选择哪一个取决于你自己

对于我过于简化的示例,我选择了简单地使用框架的 内容窗格

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

public class TimeFrame extends JFrame {

    public static void main(String args[]) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new TimeFrame().setVisible(true);
            }
        });
    }

    private JButton currentTime;
    private JLabel currentTimeLabel;
    private JTextField currentTimeField;
    private int click;
    private JTextField clicktest;

    public TimeFrame() {
        currentTimeLabel = new JLabel("The Current Time is: ");

        createTextField();
        createButton();
        createPanel();

        pack();
        setLocationRelativeTo(null);
        initialize();

    }

    private void initialize() {
        click = 0;
    }

    private void createTextField() {
        final int FIELD_WIDTH = 10;
        currentTimeField = new JTextField(FIELD_WIDTH);
        Date now = new Date();
        DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
        currentTimeField.setText("" + dateFormat.format(now));

        clicktest = new JTextField(FIELD_WIDTH);
        clicktest.setText(" " + click);

    }

    private void createButton() {
        currentTime = new JButton("Display Current Time");

        ActionListener listener = new AddCurrentTimeListener();
        currentTime.addActionListener(listener);

    }

    private void createPanel() {
        setLayout(new FlowLayout());
        //panel.addActionListener(backgroundListener);
        add(currentTimeLabel);
        add(currentTimeField);
        add(currentTime);
        add(clicktest);
    }

    class AddCurrentTimeListener implements ActionListener {

        public void actionPerformed(ActionEvent event) {

            new java.util.Date();
            Date now = new Date();
            DateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
            currentTimeField.setText("" + dateFormat.format(now));
            getClass();
            if (click < 4) {
                click++;
            } else {
                click = click - 4;
            }

            clicktest.setText("" + click);

            if (click == 0) {
                getContentPane().setBackground(Color.ORANGE);
            } else if (click == 1) {
                getContentPane().setBackground(Color.YELLOW);
            } else if (click == 2) {
                getContentPane().setBackground(Color.BLUE);
            } else if (click == 3) {
                getContentPane().setBackground(Color.GREEN);
            } else if (click == 4) {
                getContentPane().setBackground(Color.PINK);
            }
            repaint();
        }

    }

}

免责声明:

就我个人而言,我会避免直接从 JFrame getContentPane )

就我个人而言,我会从一个 面板 然后把它添加到我想要的每个容器中