java - JTextArea 中正在执行写入操作

Question

我编写了一个应用程序，它根据 x : f(x) 列表创建图形图像。在 GUI 中，它应该显示当前正在图形上写入的对，但 JTextArea 仅在生成图像的循环完成后显示消息。如何实时显示消息？

我想过使用多线程，但还是不行。

下面是图形生成器的代码:

public static void processFile(String filename, String currentDir){
    File file = new File(filename);

    LogWindow logWindow = showLogWindow();

    String line, function;
    TreeMap<Integer, Integer> dataSet = null;

    try(BufferedReader reader = new BufferedReader(new FileReader(file))) {
        logWindow.log("Starting processing of file " + file.getName());
        skipHeader(reader, Constantes.HEADER_LINES);
        while ((line = reader.readLine()) != null){
            if(line.startsWith("function ")){
                function = line.substring(25, 35).trim();

                if(dataSet != null){
                    logWindow.log("Graph of function " + function + " created.");
                    Graph demo = new Graph(dataSet);
                    demo.writeAsPNG(currentDir + File.separator + function + ".png");
                }

                dataSet = new TreeMap<Integer, Integer>();
            }else{                  
                int x = Integer.valueOf(line.substring(20,25).trim());
                int fX = Integer.valueOf(line.substring(25,30).trim());
                dataSet.put(x, fx);
                logWindow.log("Adding values of x = " + x + " and f(x) = " + fX);
            }
        }

        //Writing last set of data
        logWindow.log("Graph of function " + function + " created.");
        Graph demo = new Graph(dataSet);
        demo.writeAsPNG(currentDir + File.separator + function + ".png");
    } catch (FileNotFoundException e) {
        //TODO log this better
        e.printStackTrace();
    } catch (IOException e) {
        //TODO log this better
        e.printStackTrace();
    }   
}

这是 LogWindow 类的代码

public class LogWindow extends JPanel {
private JTextArea log;

public LogWindow() {
    super(new BorderLayout());
            log = new JTextArea(5,40);
            log.setMargin(new Insets(5,5,5,5));
            log.setEditable(false);
            JScrollPane logScrollPane = new JScrollPane(log);
            add(logScrollPane, BorderLayout.CENTER);
}

public void log(String message){
        LogThread t = new LogThread(log, message);
    t.start();
    try {
        t.join();
    } catch (InterruptedException e) {
        // TODO Log this better
        e.printStackTrace();
    }
}
}

class LogThread extends Thread{
JTextArea log;
String message;

public LogThread(JTextArea log, String message) {
    this.log = log;
    this.message = message;
}

@Override
public void run() {
    log.append(message + Constantes.lineBreak);
    log.setCaretPosition(log.getDocument().getLength());        
}
}

提前致谢

Answer 1

• 您的代码不完整，请发布 SSCCE/MVCE

  ---

• 您对Concurency in Swing有疑问，Swing 是单线程的，所有更新都已可见 AWT/Swing GUI must be on EDT

• 通过将 log.append(message + Constantes.lineBreak); 包装到 invokeLater()

中快速修复

• 不知道为什么会出现t.join();

<小时/>

• (重复调用)代码行 log.setCaretPosition(log.getDocument().getLength()); 应替换为(仅适用于所有更新均在 EDT 上完成的情况)单个JTextArea/event 的定义。 JTextComponent

.

DefaultCaret caret = (DefaultCaret) log.getCaret();
caret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE);