我正在尝试从另一个类打印到我的JTextArea。我在我的主类Risk_Mgnt_Manager里面有类ActivityLogger调用方法Alert，这是JTextArea所在的位置。我能够将字符串传递给此方法并打印到建议，但它不会附加或setText到JTextArea。我错过了什么？
我的目标是让不同的类向ActivityLogger类发送消息，然后ActivityLogger将它发送到JTextArea。
任何例子都表示赞赏，并提前感谢您。
主要课程
package risk_mgnt_manager;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.xml.parsers.ParserConfigurationException;
import org.xml.sax.SAXException;
public class Risk_Mgnt_Manager extends JFrame{
boolean begin = false;
String message = null;
JTextArea text = new JTextArea();
JButton Start = new JButton("Start");//exit program button
JButton End = new JButton("End");//Ok button executes message creation
JButton Exit = new JButton("Exit Program");
public void Alert(String a){
System.out.println(a); // This is printing correctly
text.append(a + "\n"); // why won't this display the string?
}
public Risk_Mgnt_Manager(){
text.setEditable(false);
text.setWrapStyleWord(true);
text.setLineWrap(true);
JScrollPane scroll = new JScrollPane(text);
setLayout(new GridLayout(2, 3, 5, 5)); //LayoutManager Setup
JPanel myPanel = new JPanel(new GridLayout(3,0));
//JPanel myPanel2 = new JPanel(new GridLayout(1, 1));
//JPanel myPanel3 = new JPanel(new GridLayout(1, 1));
JPanel myPanel4 = new JPanel(new GridLayout(1, 1));
myPanel.add(new JLabel("Start Automated Processes: "));
myPanel.add(Start);
myPanel.add(new JLabel("End Automated Processes: "));
myPanel.add(End);
myPanel.add(new JLabel(" "));
myPanel.add(Exit);
myPanel4.add(text);
Start.addActionListener(new startActions());//Listener for button 1
End.addActionListener(new stopActions());//Listener for button 2
Exit.addActionListener(new Quit());//Listener for button 2
add(myPanel);
//add(myPanel2);
//add(myPanel3);
add(myPanel4);
}
public void StartAutomation(boolean start) throws SAXException, ParserConfigurationException, IOException, SQLException{
//calls test class
Test t = new Test();
t.mainTest(begin);
//ignore these classes
// Step one import settlement data from FIX 1 settlement tables
ImportSettles tbl = new ImportSettles();
//tbl.DataTransfer(begin);
// Step two import Real-Time price data from t_span_price on FIX 1
ImportSpanPrice tbl2 = new ImportSpanPrice();
//tbl2.DataTransfer1(begin);
// Step three import from xml file
ImportTradeData tbl3 = new ImportTradeData();
//tbl3.parseXML(begin);
// Step four not used as of 11/26/2013
ImportFirmRpt tbl4 = new ImportFirmRpt();
// Step five import poew.csv file
ImportPOEW tbl5 = new ImportPOEW();
//tbl5.csvImportPOEW(begin);
// Step six import paycollect.csv file
ImportPaycollect tbl6 = new ImportPaycollect();
//tbl6.csvImportPaycollect(begin);
// Step seven import data from RISK 1
ImportSecDeposit tbl7 = new ImportSecDeposit();
//tbl7.DataTransfer2(begin);
// Step 8 import FCM financial info, WinJammer not used as of 11/26/2013
ImportFCM tbl8 = new ImportFCM();
// Step nine import CGM_post.csv file
ImportCGMPost tbl9 = new ImportCGMPost();
//tbl9.csvImportCGMPost(begin);
// Step ten import RM_Intraday_paycollect.csv
ImportIntraday tbl10 = new ImportIntraday();
//tbl10.csvImportIntra(begin);
}
private static void ProjectFrame(){
Risk_Mgnt_Manager projectFrame = new Risk_Mgnt_Manager();
projectFrame.setSize(500, 300); //JFrame size set
projectFrame.setLocationRelativeTo(null); //JFrame centered to center of screen
projectFrame.setTitle("Automation Control"); //JFrame Title
projectFrame.setVisible(true);//JFrame is visible upon start of program
projectFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] args) {
ProjectFrame();
}
static class Quit implements ActionListener {
public void actionPerformed (ActionEvent e) {
//Once Exit JButton is pressed the program exits
System.exit(0);
}
}
public class startActions implements ActionListener {
public void actionPerformed (ActionEvent e) {
//Once Exit JButton is pressed the program exits
begin = true;
try {
StartAutomation(begin);
} catch (SAXException ex) {
Logger.getLogger(Risk_Mgnt_Manager.class.getName()).log(Level.SEVERE, null, ex);
} catch (ParserConfigurationException ex) {
Logger.getLogger(Risk_Mgnt_Manager.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(Risk_Mgnt_Manager.class.getName()).log(Level.SEVERE, null, ex);
} catch (SQLException ex) {
Logger.getLogger(Risk_Mgnt_Manager.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
public class stopActions implements ActionListener {
public void actionPerformed (ActionEvent e) {
//Once Exit JButton is pressed the program exits
begin = false;
try {
StartAutomation(begin);
} catch (SAXException ex) {
Logger.getLogger(Risk_Mgnt_Manager.class.getName()).log(Level.SEVERE, null, ex);
} catch (ParserConfigurationException ex) {
Logger.getLogger(Risk_Mgnt_Manager.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(Risk_Mgnt_Manager.class.getName()).log(Level.SEVERE, null, ex);
} catch (SQLException ex) {
Logger.getLogger(Risk_Mgnt_Manager.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
测试课
package risk_mgnt_manager;
import java.util.Date;
/**
*
* @author bgilbert
*/
public class Test {
public void mainTest(boolean a){
ActivityLogger act = new ActivityLogger();
act.logger("Testing message reporting " + new Date(), 1, true);
}
}
ActivityLogger类
package risk_mgnt_manager;
/**
*
* @author MLaMeyer
*/
public class ActivityLogger{
private String message;
// this will perform different purposes once I can print to JTextArea
public void logger(String log, int type, boolean execution){
if (execution == true) {
message = log;
}
if (execution == false) {
message = log;
}
print();
}
// calls method Alert in main class and passes the string correctly
public void print(){
Risk_Mgnt_Manager m = new Risk_Mgnt_Manager();
m.Alert(message);
}
}
答案 0 :(得分：1)
您需要在单独的Thread中更新UI，我的意思是UI相关的操作应该在Event调度线程上运行。在您的ActivityLogger类中添加构造函数，如Hovercraft的解决方案，然后尝试，
SwingUtilities.invokeLater(new Runnable() {
public void run() {
text.append(a+"\n");
}
});
答案 1 :(得分：1)
您的程序打印到另一个类，而不是打印在显示的对象中：
public void print(){
Risk_Mgnt_Manager m = new Risk_Mgnt_Manager();
m.Alert(message);
}
当您创建新的Risk_Mgnt_Manager时，您只需创建一个新的完全唯一的Risk_Mgnt_Manager对象，即未显示的对象。打印到它将不会影响显示的。
解决方案是将对logger类的引用传递给实际显示的Risk_Mgnt_Manager对象。
public class ActivityLogger{
private String message;
private Risk_Mgnt_Manager m; // ***** added
public ActivityLogger(Risk_Mgnt_Manager m) {
this.m = m; // ****** added
}
// this will perform different purposes once I can print to JTextArea
public void logger(String log, int type, boolean execution){
if (execution == true) {
message = log;
}
if (execution == false) {
message = log;
}
print();
}
// calls method Alert in main class and passes the string correctly
public void print(){
// Risk_Mgnt_Manager m = new Risk_Mgnt_Manager();
SwingUtilities.invokeLater(new Runnable() {
public void run() {
m.Alert(message);
}
});
}
}
无论你做什么，都不要试图解决这个问题，因为这条道路会导致痛苦。
答案 2 :(得分：0)
首先，在constructor。
public Risk_Mgnt_Manager(){
setVisible(true);
}
然后按照Hovercraft的解决方案通过引用传递。