Swing PropertyChangeSupport 动态更新 JTextArea

Question

我正在尝试建立关于 SwingPropertyChangeSupport 问题的答案

我正在尝试修改此处给出的代码，这是非常有用的 Hovercraft Full Of Eels 的回答： WindowListener does not work as expected，允许在通过输入对话框输入更改时更新显示的数组。

阵列更新正常，但未在 GUI 中刷新。我希望有人能告诉我哪里出错了。

代码如下：

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.event.SwingPropertyChangeSupport;

public class Main {
public static void main(String[] arg) {
    GuiForUpdate display = new GuiForUpdate();
    display.setVisible(true);
}
}

class GuiForUpdate extends JFrame implements ActionListener {

/**
 * 
 */
private static final long serialVersionUID = 1L;
private FocusListener focusListener;
private String mList;
private JButton changeArrayButton;
private JTextArea codeIn, displayOutput;
private int arrayIndex;
private JPanel displayPanel;
private ArrayForUpdating arrayForUpdate = new ArrayForUpdating();

public GuiForUpdate() {
    setSize(224, 180);
    layoutLeft();
    layoutDisplay();
    layoutBottom();
}

/**
 * adds a display area for array
 */
public void layoutDisplay() {
    displayPanel = new JPanel();
    add(displayPanel, BorderLayout.CENTER);
    displayOutput = new JTextArea();
    displayPanel.add(displayOutput);
    displayOutput.addFocusListener(focusListener);

    mList = arrayForUpdate.getBoundProperty();

    arrayForUpdate.addPropertyChangeListener(new PropertyChangeListener() {

        @Override
        public void propertyChange(PropertyChangeEvent pcEvt) {
            if (pcEvt.getPropertyName().equals(
                    ArrayForUpdating.BOUND_PROPERTY)) {
                mList = (pcEvt.getNewValue().toString());
            }
        }
    });

    displayOutput.setText(mList);
}

/**
 * adds left hand side elements to left of GUI
 */
public void layoutLeft() {
    JPanel left = new JPanel();
    add(left, BorderLayout.WEST);
    codeIn = new JTextArea(2, 2);
    left.add(codeIn);
    codeIn.addFocusListener(focusListener);
}

/**
 * adds bottom elements to bottom of GUI
 */
public void layoutBottom() {
    JPanel bottom = new JPanel();
    changeArrayButton = new JButton("Modify array");
    changeArrayButton.addActionListener(this);
    bottom.add(changeArrayButton);
    add(bottom, BorderLayout.SOUTH);
}

/**
 * Process button clicks
 */
public void actionPerformed(ActionEvent ae) {

    if (ae.getSource() == changeArrayButton) {

        // first check if any code entered
        if (codeIn.getText().trim().length() != 0) {

            // call modifyMemory() method
            modifyArray();

        } else
            JOptionPane.showMessageDialog(null,
                    "Please enter something first.");
    }
}

/**
 * method to process modify array
 */
public void modifyArray() {

    // show dialog to retrieve entered address
    String addressToModify = (String) JOptionPane
            .showInputDialog("At which location?");

    // confirm if a string was entered
    if ((addressToModify != null) && (addressToModify.length() > 0)) {

        // convert to integer if decimal address entered
        arrayIndex = Integer.parseInt(addressToModify);
    }
    // pass as integer
    processInput(arrayIndex);
}

public void processInput(int a) {

    String newValue = codeIn.getText();
    arrayForUpdate.instructionsIn(newValue, a);
}
}

class ArrayForUpdating {

public static final String BOUND_PROPERTY = "bound property";
private String boundProperty = "";

private SwingPropertyChangeSupport spcSupport = new SwingPropertyChangeSupport(
        this);
private StringBuilder mList;
private int[] myArray;

public ArrayForUpdating() {

    myArray = new int[5];
    for (int i = 0; i < myArray.length; i++) {
        myArray[i] = 0;
    }
    setArrayyDisplayString();
}

/** 
 * method to create formatted string of array
 */
public void setArrayyDisplayString() {

    // create StringBuilder for display in memory tab
    mList = new StringBuilder();
    for (int i = 0; i < myArray.length; i++) {

        mList.append(String.format("%10s %02d %10s %02d", "Pos:   ", i,
                "Value:  ", myArray[i]));
        mList.append("\n");
    }
    setBoundProperty(mList.toString());
}

/**
 * This method takes in a string passed through from the GUI
 */
public void instructionsIn(String codeIn, int loc) {

    String code = codeIn.trim();
    int oc = Integer.parseInt(code);

    // add the data to the array
    setArrayData(loc, oc);
    loc++;
}

/**   
 * method to add data to the array
 */
public void setArrayData(int a, int memData) {
    myArray[a] = memData;

    // print array to console for checking
    for (int i = 0; i < myArray.length; i++) {
        System.out.println("location: " + i + " value: " + myArray[i]);
    }
    setArrayyDisplayString();
}

public SwingPropertyChangeSupport getSpcSupport() {
    return spcSupport;
}

public void setSpcSupport(SwingPropertyChangeSupport spcSupport) {
    this.spcSupport = spcSupport;
}

public String getBoundProperty() {
    return boundProperty;
}

public void setBoundProperty(String boundProperty) {
        String oldValue = this.boundProperty;
        System.out.println("old = " + oldValue);
        String newValue = boundProperty;
        System.out.println("new = " + newValue);
        this.boundProperty = newValue;
        spcSupport.firePropertyChange(BOUND_PROPERTY, oldValue, newValue);
    }

    public void addPropertyChangeListener(PropertyChangeListener listener) {
    spcSupport.addPropertyChangeListener(listener);
    }
}

-编辑- 希望消除编译错误。

Answer 1

代码看起来或多或少是正确的（即我找不到任何明显的错误）。您应该尝试在调试器中运行它，并在调试代码时遇到问题时提出一个新问题。

Answer 2

这是一个在无模式对话框中使用ObservedPanel 的完整示例。

public class PropertyChangeDialog extends JPanel {

    private JLabel label = new JLabel("null", JLabel.CENTER);
    private ObservedPanel observed = new ObservedPanel();

    public PropertyChangeDialog() {
        this.setBorder(BorderFactory.createTitledBorder("Observer"));
        this.add(label);
        observed.addPropertyChangeListener(new PropertyChangeListener() {

            @Override
            public void propertyChange(PropertyChangeEvent e) {
                if (e.getPropertyName().equals(ObservedPanel.PHYSICIST)) {
                    String value = e.getNewValue().toString();
                    label.setText(value);
                }
            }
        });
    }

    private void display() {
        JFrame f = new JFrame("PropertyChangeDialog");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(this);
        f.pack();
        f.setLocationByPlatform(true);
        f.setVisible(true);
        JDialog dialog = new JDialog(f);
        dialog.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
        dialog.add(observed);
        dialog.pack();
        dialog.setLocationRelativeTo(null);
        dialog.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                new PropertyChangeDialog().display();
            }
        });
    }
}

Answer 3

当我将displayOutput.setText(mList) 放在propertyChange 方法中时，它起作用了：

@Override
public void propertyChange(PropertyChangeEvent pcEvt) {
    if (pcEvt.getPropertyName().equals(
        ArrayForUpdating.BOUND_PROPERTY)) {
        mList = (pcEvt.getNewValue().toString());
        displayOutput.setText(mList);
    }
}

感谢大家的帮助，尤其是您的耐心。