我投降。现在尝试了几个星期，以找出阻止接收到的串行数据被我的代码的图形部分更新的原因。第一次用Java编程。拥有大约 15 年的微型编程经验，我习惯于解决我自己的问题，但这超出了该策略有效的范围。我的应用程序包含两个文件。
一个文件来自 RXTX 项目，每秒捕获两次以多个数据包发送的串行数据。这就像一个魅力（花了一些时间），我可以看到捕获的数据是正确且稳定的。
另一个文件是图形文件，包含大约 80 个菜单，最终用户可以在其中读取和有时写入值。到目前为止，导航是通过按钮和滚动条上的鼠标事件完成的。这部分也可以正常工作。可以读取、更改和保存值等。
我被卡住的部分是串行文件中的更新值永远不会更新图形屏幕。尝试了数百个示例和教程（许多来自此站点），但没有成功。
对象相关语言的概念对我来说是新的并且仍然很混乱。很确定我的问题涉及继承和类。线程是另一个候选者...已将代码缩减到仍然可以运行并提出我的问题的最小大小，并希望有人能看到什么是错的。
package components;
import gnu.io.CommPort;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import javax.swing.SwingUtilities;
public class SerialComm extends ScreenBuilder implements java.util.EventListener {
InputStream in;
public SerialComm() {
super();
}
public interface SerialPortEventListener
extends java.util.EventListener {
}
void connect(String portName) throws Exception {
CommPortIdentifier portIdentifier = CommPortIdentifier.getPortIdentifier("COM1");
if (portIdentifier.isCurrentlyOwned()) {
System.out.println("Error: Port is currently in use");
} else {
CommPortIdentifier.getPortIdentifier("COM1");
System.out.println("" + portName);
CommPort commPort = portIdentifier.open("COM1", 2000);
if (commPort instanceof SerialPort) {
SerialPort serialPort = (SerialPort) commPort;
serialPort.setSerialPortParams(115200, SerialPort.DATABITS_8, SerialPort.STOPBITS_2, SerialPort.PARITY_NONE);
InputStream in = serialPort.getInputStream();
OutputStream out = serialPort.getOutputStream();
serialPort.addEventListener(new SerialComm.SerialReader(in));
serialPort.notifyOnDataAvailable(true);
(new Thread(new SerialComm.SerialReader(in))).start();
// TX functionality commented for now
// (new Thread(new SerialWriter(out))).start();
} else {
System.out.println("Error: Only serial ports are handled by this example.");
}
}
}
public class SerialReader extends SerialComm implements Runnable,
gnu.io.SerialPortEventListener {
public SerialReader(InputStream in) {
this.in = in;
}
@Override
public void run() {
count=11; // just for test. run is normally empty
count2=count; // and real code runs within serialEvent()
System.out.println("SerialReader " + count);
dspUpdate(); // do some desperate stuff in graphics file
System.out.println("Post Update " + count);
}
@Override
public void serialEvent(SerialPortEvent event) {
System.out.println("SerialEvent");
switch (event.getEventType()) {
case SerialPortEvent.DATA_AVAILABLE:
try {
synchronized (in) {
while (in.available() < 0) {
in.wait(1, 800000);
} //in real code RX data is captured here twice a sec
} //and stored into buffers defined in ScreenBuilder
//dspUpdate() is called from here to make ScreenBuilder update its screen
//That never happens despite all my attempts
} catch (IOException e) {
System.out.println("IO Exception");
} catch (InterruptedException e) {
System.out.println("InterruptedException caught");
}
}
}
}
/* "main" connect PC serial port and start graphic part of application
* To demonstrate problem with no serial data stream present
* order of init between serial port and graphics are switched
*/
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
ScreenBuilder screen = new ScreenBuilder();
screen.createAndShowGUI();
System.out.println("Created GUI");
}
});
try {
(new SerialComm()).connect("COM1");
} catch (Exception e) {
System.out.println("Error");
e.printStackTrace();
}
}
}
和图形文件
package components;
import java.awt.*;
import javax.swing.SwingUtilities;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.event.*;
public class ScreenBuilder extends JPanel implements ActionListener {
public Font smallFont = new Font("Dialog", Font.PLAIN, 12);
Color screenColor;
Color lineColor;
short btn=0;
short count;
short count2;
Button helpButton;
public static void createAndShowGUI() {
System.out.println("Created GUI on EDT? "
+ SwingUtilities.isEventDispatchThread());
JFrame f = new JFrame("JUST A TEST");
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(new ScreenBuilder());
f.pack();
f.setVisible(true);
}
public void dspButton() {
setLayout(null);//
helpButton = new Button("?");
helpButton.setLocation(217, 8); // set X, Y
helpButton.setSize(16, 14); //Set Size X, Y //
helpButton.addActionListener(this);
add(helpButton);
setBackground(Color.black);
helpButton.setBackground(Color.black);
screenColor = Color.black;
helpButton.setForeground(Color.white);
lineColor = Color.white;
}
@Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == helpButton) {
count2++;
System.out.println("Pressed Button ");
repaint();
}
}
public ScreenBuilder() {
setBorder(BorderFactory.createLineBorder(Color.black));
}
@Override
public Dimension getPreferredSize() {
return new Dimension(240, 180);
}
public void dspUpdate() {
/*
* This function is called from SerialComm
* Should be called when serial packets have arrived (twice a second)
* and update screen with values from serial stream
* For now just a test var to validate that values from SerialComm
* get to here (they do)
*/
count++;
System.out.println("Update Count " + count);
System.out.println("Update Count2 " + count2);
// revalidate(); // another futile attempt to update screen
// repaint();
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(lineColor);
g.setFont(smallFont);
count++;
g.drawString("" + count, 130, 20);
g.drawString("" + count2, 150, 20);
if (btn == 0) {
dspButton();
btn = 1;
}
}
}