我正在尝试为panel_1 JPanel创建一个绘画组件，但我不知道该怎么做。这是我的班级。
此代码有效，但它不会绘制panel_1。
如果我尝试将其添加到面板而不进行绘制，它就可以正常工作。
此外，我需要该面板以给定的间隔自动刷新（重新绘制）。
请帮助我。 ：d
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.Timer;
import javax.swing.border.EmptyBorder;
public class GUI extends JFrame implements ActionListener {
private JPanel contentPane;
private JTextField textField;
private JTextField textField_1;
private JTextField textField_2;
private JTextField textField_3;
private JButton btnStop, btnStart;
private JComboBox comboBox_1, comboBox;
private Manager manager = new Manager();
private String arrMin, arrMax, svcMin, svcMax, simTime;
private JTextField textField_4;
private JPanel panel_1 = new JPanel(){
@Override
public void paintComponent(Graphics g){
paintComponents(g);
panel_1.setBackground(Color.orange);
panel_1.setVisible(true);
System.out.println("Just testing");
}
};
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
GUI frame = new GUI();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the frame.
*/
public GUI() {
setResizable(false);
setForeground(Color.DARK_GRAY);
setBackground(Color.DARK_GRAY);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 700, 500);
contentPane = new JPanel();
contentPane.setForeground(Color.DARK_GRAY);
contentPane.setBackground(Color.DARK_GRAY);
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
JPanel panel = new JPanel();
panel.setBounds(12, 12, 434, 346);
panel.setForeground(Color.LIGHT_GRAY);
contentPane.add(panel);
panel.setLayout(null);
JLabel lblArrivingTime = new JLabel("Arriving time");
lblArrivingTime.setBounds(12, 367, 94, 15);
lblArrivingTime.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblArrivingTime);
JLabel lblMin = new JLabel("Min");
lblMin.setBounds(12, 395, 70, 15);
lblMin.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblMin);
JLabel lblMax = new JLabel("Max");
lblMax.setBounds(12, 418, 70, 15);
lblMax.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblMax);
textField = new JTextField();
textField.setBounds(58, 394, 48, 16);
contentPane.add(textField);
textField.setColumns(10);
textField_1 = new JTextField();
textField_1.setBounds(58, 422, 48, 15);
contentPane.add(textField_1);
textField_1.setColumns(10);
JLabel lblServiceTime = new JLabel("Service Time");
lblServiceTime.setBounds(152, 367, 105, 15);
lblServiceTime.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblServiceTime);
JLabel lblMin_1 = new JLabel("Min");
lblMin_1.setBounds(152, 395, 51, 15);
lblMin_1.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblMin_1);
JLabel lblMax_1 = new JLabel("Max");
lblMax_1.setBounds(152, 418, 70, 15);
lblMax_1.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblMax_1);
textField_2 = new JTextField();
textField_2.setBounds(209, 393, 48, 17);
contentPane.add(textField_2);
textField_2.setColumns(10);
textField_3 = new JTextField();
textField_3.setBounds(209, 417, 48, 17);
contentPane.add(textField_3);
textField_3.setColumns(10);
JLabel lblSimSetup = new JLabel("Sim. Setup");
lblSimSetup.setBounds(292, 367, 94, 15);
lblSimSetup.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblSimSetup);
JLabel lblQueue = new JLabel("Queue");
lblQueue.setBounds(292, 395, 70, 15);
lblQueue.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblQueue);
String[] numbers = { "1", "2", "3", "4" };
comboBox = new JComboBox(numbers);
comboBox.setBounds(345, 395, 75, 15);
contentPane.add(comboBox);
JLabel lblMode = new JLabel("Mode");
lblMode.setBounds(292, 418, 70, 15);
lblMode.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblMode);
String[] mode = { "Time", "Number" };
comboBox_1 = new JComboBox(mode);
comboBox_1.setBounds(345, 413, 75, 15);
contentPane.add(comboBox_1);
JLabel lblActions = new JLabel("Actions");
lblActions.setBounds(484, 367, 70, 15);
lblActions.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblActions);
btnStart = new JButton("Start");
btnStart.setBounds(482, 392, 81, 20);
contentPane.add(btnStart);
btnStop = new JButton("Stop");
btnStop.setBounds(482, 415, 81, 20);
contentPane.add(btnStop);
JLabel lblTime = new JLabel("Time");
lblTime.setBounds(292, 440, 70, 15);
lblTime.setForeground(Color.LIGHT_GRAY);
contentPane.add(lblTime);
textField_4 = new JTextField();
textField_4.setBounds(345, 438, 75, 17);
contentPane.add(textField_4);
textField_4.setColumns(10);
panel_1.setBounds(484, 12, 202, 346);
contentPane.add(panel_1);
panel_1.setLayout(null);
JTextArea textArea = new JTextArea();
textArea.setBounds(158, 12, -126, 322);
panel_1.add(textArea);
btnStop.addActionListener(this);
btnStart.addActionListener(this);
comboBox.addActionListener(this);
comboBox_1.addActionListener(this);
}
public void actionPerformed(ActionEvent e) {
if (e.getSource() == btnStop) {
this.dispose();
System.exit(NORMAL);
} else if (e.getSource() == btnStart) {
String nrQueues = (String) comboBox.getSelectedItem();
arrMin = textField.getText();
arrMax = textField_1.getText();
svcMin = textField_2.getText();
svcMax = textField_3.getText();
simTime = textField_4.getText();
int aMin = 0;
int aMax = 0;
int sMin = 0;
int sMax = 0;
int sTime = 0;
int nQueues = 1;
try {
nQueues = Integer.parseInt(nrQueues);
aMin = Integer.parseInt(arrMin);
aMax = Integer.parseInt(arrMax);
sMin = Integer.parseInt(svcMin);
sMax = Integer.parseInt(svcMax);
sTime = Integer.parseInt(simTime);
} catch (NumberFormatException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
String s = (String) comboBox_1.getSelectedItem();
System.out.println("Selected: " + s);
boolean mode = true;
if (s.equals("Time")) {
mode = true;
} else {
mode = false;
}
manager.startSimulation(aMin * 1000, aMax * 1000, sMin * 1000,
sMax * 1000, sTime * 1000, nQueues, mode);
}
}
}
当然，处理程序在这种情况下并不相关，因为我只对绘制该面板感兴趣。
答案 0 :(得分：3)
您正在调用super.paintComponents覆盖内的paintComponent方法。让人惊讶。您也使用null布局，不应该。
您正在设置背景颜色但不执行任何操作。您应该在JPanel对象上设置背景颜色，而不是在其paintComponent方法中设置背景颜色。
即，这里
panel_1.setBackground(Color.orange); // here
// !! panel_1.setBounds(484, 12, 202, 346); // you shouldn't need this!
contentPane.add(panel_1);
修改
你说：
只需在文本区域附加一个字符串即可，它会自动显示在屏幕上吗？
是的，只要考虑Swing线程规则。
答案 1 :(得分：3)
首先，这......
private JPanel panel_1 = new JPanel(){
@Override
public void paintComponent(Graphics g){
paintComponents(g);
panel_1.setBackground(Color.orange);
panel_1.setVisible(true);
System.out.println("Just testing");
}
};
不是自定义绘画的用途。您不应该从任何绘制方法内部更改组件的状态或任何组件的状态。
这可能会触发一个新的重绘请求，这会让你进入一个永无止境的绘画循环......
调用paintComponents(g);将产生StackOverflowException。您不应该以任何方式致电paintComponents（请注意最后的s），但您应该致电super.paintComponent(g);
JPanel默认可见。
就目前而言，你根本不需要做任何事情......
不要使用null布局。 Swing旨在与布局管理器一起工作，如果没有它们，屏幕无法更新就会出现问题，此外，像素完美布局是现代用户界面设计中的错觉，您无法控制字体，渲染管道或其他目标系统的各个方面可能会影响像文本这样的大元素的渲染。