java - SwingPropertyChangeSupport 从文件读取后刷新 GUI

Question

继昨晚我的问题: SwingPropertyChangeSupport to dynamically update JTextArea ，我正在尝试在读取文本文件后刷新 GUI。

我有一个包含两位整数的数组。我可以通过在文本区域中输入一串数字来动态更新它，然后选择要修改的索引。该字符串被分成两位数的部分并按顺序添加。输入字符串并单击按钮后，将调用此方法:

public void modifyArray() {

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

    // convert to integer if decimal address entered
    memAddress = Integer.parseInt(addressToModify);
    arrayForUpdate.instructionsIn(codeIn.getText(), memAddress);
}

我的这部分代码现在按预期工作。也就是说，如果我输入“123456”然后输入位置“0”(或“0000”)，则显示会更新为如下所示:

Index     0000   Value:   12
Index     0001   Value:   34
Index     0002   Value:   56
Index     0003   Value:   00

我还有一个文本文件，其中包含一个由四位数字组成的字符串，提供数组索引，然后是一系列要添加到数组中的两位数字值。我可以通过 gui 按钮/文件选择器加载它。示例文件的内容是:

0000123456

我有以下方法来处理文件:

    public void readRecord(File fileName) {

    // create file reader
    try {
        FileReader reader = null;
        try {
            // open input file
            reader = new FileReader(fileName);

            // create scanner to read from file reader
            Scanner in = new Scanner(reader);

            // read each line and remove whitespace
            while (in.hasNextLine()) {
                String line = in.nextLine().trim();
                parseRecord(line);
            }

        } finally {
            // close reader assuming it was successfully opened
            if (reader != null)
                reader.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
    }
  }

public void parseRecord(String record) {

    // create address substring from start, 4 long
    String addrString = record.substring(0, 3);
    int s1Address = Integer.parseInt(addrString);

    // create binary data substring (4 from start, up to end)
    String dataString = record.substring(4, record.length());

    // pass data string as parameter to InstructionsIn method
    arrayForUpdate.instructionsIn(dataString, s1Address);
}

在上述两种情况下，都会调用“instructionsIn”方法。在第一种情况下，这会导致显示被更新，但在第二种情况下却没有，我不知道为什么。我希望有人能够发现我遗漏的东西。

这是运行的代码的完整简化版本:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.FocusListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.event.SwingPropertyChangeSupport;

public class PropertyChangeExample extends JFrame implements ActionListener {

private static final long serialVersionUID = 1L;
private String addressToModify, mList;
private int memAddress;
private JTextArea codeIn, displayOutput;
private S_Record sRec;
private JButton loadButton, modifyArrayButton;
private FocusListener focusListener;
private JPanel displayPanel;
private ArrayForUpdate arrayForUpdate = new ArrayForUpdate();

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

public PropertyChangeExample() {
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(450, 170);
    layoutLeft();
    layoutDisplay();
    layoutBottom();
}

public void layoutDisplay() {
    displayPanel = new JPanel();
    add(displayPanel, BorderLayout.CENTER);
    displayOutput = new JTextArea(32, 38);
    displayPanel.add(displayOutput);
    displayOutput.addFocusListener(focusListener);

    mList = arrayForUpdate.getBoundProperty();
    displayOutput.setText(mList);

    arrayForUpdate.addPropertyChangeListener(new PropertyChangeListener() {

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

public void layoutLeft() {
    JPanel left = new JPanel();
    add(left, BorderLayout.WEST);
    codeIn = new JTextArea(10, 7);
    left.add(codeIn, BorderLayout.NORTH);
    codeIn.addFocusListener(focusListener);
}

public void layoutBottom() {
    JPanel bottom = new JPanel();
    bottom.setBackground(Color.LIGHT_GRAY);
    loadButton = new JButton("Load file");
    loadButton.addActionListener(this);
    bottom.add(loadButton);
    add(bottom, BorderLayout.SOUTH);
    modifyArrayButton = new JButton("Add value to array");
    modifyArrayButton.addActionListener(this);
    bottom.add(modifyArrayButton);
}

public void actionPerformed(ActionEvent ae) {
    if (ae.getSource() == modifyArrayButton) {
        modifyArray();
    }

    if (ae.getSource() == loadButton) {
        processInputFile();
    }
}

public void modifyArray() {
    addressToModify = (String) JOptionPane
            .showInputDialog("At which location?");

    // convert to integer if decimal address entered
    memAddress = Integer.parseInt(addressToModify);
    arrayForUpdate.instructionsIn(codeIn.getText(), memAddress);
}

public void processInputFile() {

    sRec = new S_Record();
    JFileChooser chooser = new JFileChooser();
    int returnVal = chooser.showOpenDialog(getParent());
    if (returnVal == JFileChooser.APPROVE_OPTION) {
        // create the file
        File file = chooser.getSelectedFile();

        // pass to readRecord method in S_Record class
        sRec.readRecord(file);
    }
 }
}

class S_Record {

private ArrayForUpdate arrayForUpdate = new ArrayForUpdate();

public void readRecord(File fileName) {

    // create file reader
    try {
        FileReader reader = null;
        try {
            // open input file
            reader = new FileReader(fileName);

            // create scanner to read from file reader
            Scanner in = new Scanner(reader);

            // read each line and remove whitespace
            while (in.hasNextLine()) {
                String line = in.nextLine().trim();
                parseRecord(line);
            }
        } finally {
            // close reader assuming it was successfully opened
            if (reader != null)
                reader.close();
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

public void parseRecord(String record) {

    // create address substring from start, 4 long
    String addrString = record.substring(0, 3);

    int s1Address = Integer.parseInt(addrString);

    // create binary data substring (4 from start, up to end)
    String dataString = record.substring(4, record.length());

    // pass data string as parameter to InstructionsIn method
    arrayForUpdate.instructionsIn(dataString, s1Address);
 }
}

class ArrayForUpdate {

public static final String BOUND_PROPERTY = "bound property";
private String boundProperty = "";
private SwingPropertyChangeSupport spcSupport = new SwingPropertyChangeSupport(
        this);
private int[] myArray;
private final int MEM_LOCATIONS = 6;
/** StringBuilder object for displaying memory */
private StringBuilder mList;

public ArrayForUpdate() {

    myArray = new int[MEM_LOCATIONS];
    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 %04x %10s %02x", "Index:   ", 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 len = code.length();
    int chunkLength = 2; // the length of each chunk of code
    int i = 0;

    // traverse entered code and split into 2 digit chunks
    for (i = 0; i < len; i += chunkLength) {

        String chunk = code.substring(i, Math.min(len, i + chunkLength));
        int oc = Integer.parseInt(chunk, 16);

        // 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;
    setArrayyDisplayString();
}

public String getBoundProperty() {
    return boundProperty;
}

/**
 * Method to implement changes to array for display
 * 
 * @param boundProperty - the String representing the memory array
 */
public void setBoundProperty(String boundProperty) {
    String oldValue = this.boundProperty;
    String newValue = boundProperty;
    this.boundProperty = newValue;
    spcSupport.firePropertyChange(BOUND_PROPERTY, oldValue, newValue);
}

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

Answer 1

这看起来是引用的问题。

您似乎至少有两个 ArrayForUpdate 对象，一个由 GUI 监听，另一个完全不同的实例保存在 S_Record 类中。后一种是从文件中获取信息的，而前一种，GUI 监听的不是。解决方案:确保只有一个 ArrayForUpdate 对象在两个地方都使用。也许您可以通过其构造函数将 GUI 实例的引用传递到您的 S_Record 对象中？