我用 Netbeans 制作了一个 JAVA GUI 应用程序。它使用 RXTX 库与 Arduino 进行通信。一切正常。该程序能够从 Arduino 获取串行输出。 arduino 在一秒延迟后重复发送字符串 0 或 1。我编写的程序是这样的:如果它接收到 0，则将 jPanel 着色为红色；如果接收到 1，则将 jPanel 着色为绿色。此外，2 个按钮也使用相同的 jPanel 颜色。但是当运行程序时，当我按下按钮时，它们会按照我想要的方式为 jPanel 着色。但是 0 和 1 上的 if 语句无法为 jPanel 着色。我已经通过放置一些其他语句来检查 if 条件循环工作正常，但仍然无法设置 jPanel 的颜色。 这是我的代码-
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.awt.Color;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.util.Enumeration;
public class tets extends javax.swing.JFrame implements SerialPortEventListener {
SerialPort serialPort = null;
private static final String PORT_NAMES[] = {
// "/dev/tty.usbmodem", // Mac OS X
// "/dev/usbdev", // Linux
// "/dev/tty", // Linux
// "/dev/serial", // Linux
"COM3", // Windows
};
private String appName;
private BufferedReader input;
private OutputStream output;
private static final int TIME_OUT = 1000; // Port open timeout
private static final int DATA_RATE = 9600; // Arduino serial port
String inputLine;
public boolean initialize() {
try {
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();
// Enumerate system ports and try connecting to Arduino over each
//
System.out.println( "Trying:");
while (portId == null && portEnum.hasMoreElements()) {
// Iterate through your host computer's serial port IDs
//
CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
System.out.println( " port" + currPortId.getName() );
for (String portName : PORT_NAMES) {
if ( currPortId.getName().equals(portName)
|| currPortId.getName().startsWith(portName)) {
// Try to connect to the Arduino on this port
//
// Open serial port
serialPort = (SerialPort)currPortId.open(appName, TIME_OUT);
portId = currPortId;
System.out.println( "Connected on port" + currPortId.getName() );
break;
}
}
}
if (portId == null || serialPort == null) {
System.out.println("Oops... Could not connect to Arduino");
return false;
}
// set port parameters
serialPort.setSerialPortParams(DATA_RATE,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);
// add event listeners
serialPort.addEventListener(this);
serialPort.notifyOnDataAvailable(true);
// Give the Arduino some time
try { Thread.sleep(2000); } catch (InterruptedException ie) {}
return true;
}
catch ( Exception e ) {
e.printStackTrace();
}
return false;
}
public synchronized void close() {
if ( serialPort != null ) {
serialPort.removeEventListener();
serialPort.close();
}
}
//
// Handle serial port event
//
public synchronized void serialEvent(SerialPortEvent oEvent) {
//System.out.println("Event received: " + oEvent.toString());
try {
switch (oEvent.getEventType() ) {
case SerialPortEvent.DATA_AVAILABLE:
if ( input == null ) {
input = new BufferedReader(
new InputStreamReader(
serialPort.getInputStream()));
}
inputLine = input.readLine();
System.out.println(inputLine);
startx(inputLine);
break;
default:
break;
}
}
catch (Exception e) {
System.err.println(e.toString());
}
}
/**
* Creates new form Parking
*/
public tets() {
initComponents();
appName = getClass().getName();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
panel1 = new java.awt.Panel();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jTextField2 = new javax.swing.JTextField();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
javax.swing.GroupLayout panel1Layout = new javax.swing.GroupLayout(panel1);
panel1.setLayout(panel1Layout);
panel1Layout.setHorizontalGroup(
panel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 250, Short.MAX_VALUE)
);
panel1Layout.setVerticalGroup(
panel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGap(0, 206, Short.MAX_VALUE)
);
jButton1.setText("connect");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jButton2.setText("jButton2");
jButton2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton2ActionPerformed(evt);
}
});
jTextField2.setText("jTextField2");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(70, Short.MAX_VALUE)
.addComponent(panel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(80, 80, 80))
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(107, 107, 107)
.addComponent(jButton1)
.addGap(29, 29, 29)
.addComponent(jButton2))
.addGroup(layout.createSequentialGroup()
.addGap(158, 158, 158)
.addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap(15, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jButton2))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(panel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(15, 15, 15)
.addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap())
);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
jTextField2.setText("Parked");
panel1.setBackground(Color.RED);
}
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
panel1.setBackground(Color.GREEN);
jTextField2.setText("Free");
}
private void startx(String inputLine){
int a = Integer.parseInt(inputLine);
Color color;
if (a == 0){
color = Color.RED;
panel1.setBackground(color);
}
else{
color = Color.GREEN;
panel1.setBackground(color);
}
System.out.println(color);
panel1.repaint();
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
tets test = new tets();
if ( test.initialize() ) {
try { Thread.sleep(2000); } catch (InterruptedException ie) {}
}
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(tets.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(tets.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(tets.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(tets.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new tets().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JTextField jTextField2;
private java.awt.Panel panel1;
// End of variables declaration
}
提前致谢:)
最佳答案
我认为这可能是由于 EDT 上未处理串行端口事件。 如果将 startx(inputLine) 调用包装在 SwingUtilities.invokeLater() 中会怎样？
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
startx(inputLine);
}
});
看看是否有效。
编辑:问题是当您使其可见时，您正在 main 方法中重新创建 tets 实例。因此，初始化的实例甚至没有被使用。使用已经创建的 tets 实例(在 main 方法中将 new tets().setVisible(true); 替换为 test.setVisible(true)，您必须将变量 test 更改为 Final。)以及上述建议(稍后使用 invoke)，它将起作用。
关于java - JAVA GUI 应用程序中的 jPanel 颜色未改变，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/35503675/