Java Swing（FileReader）读取text.file并写入JList - 随机工作Oo

Question

您好 我正在研究一个JavaSwing应用程序但是有一个问题...我不确切知道，但我认为它可能是一个（重新）绘制问题：S - 无论如何这是我的代码：

MAIN：

public class QickSort {

protected static ArrayList<String> input;
private static File file = new File("C:/Users/save.txt");

public static void main(String[] args) throws Exception {

    BufferedReader reader;
    String line = null;

    try {
        input = new ArrayList<String>();

        reader = new BufferedReader(new FileReader(file));

        while ((line = reader.readLine()) != null) {
            input.add(line);
        }
        reader.close();

    } catch (Exception ex) {
        System.out.println("Can't load file on path.. - " + ex);
        ex.printStackTrace();
    }
    System.out.println(input.size());
    JFrame.setDefaultLookAndFeelDecorated(false);
    MasterWin win = new MasterWin(input);
}

}

UI：

public class MasterWin {

private JFrame frame;
private JTextField txtFieldPath;
private JButton btnBrowse;
private JButton btnAddPathTo;
private JLabel lblChosenFolderpaths;
private JButton btnRemove;
private JButton btnNext;
protected static ImageIcon icon = new ImageIcon(MasterWin.class.getResource("/View/logo_sml.gif"));
private JScrollPane scrollPane;
private JList linkList;
private List<String> test;

/**
 * Create the application.
 */
public MasterWin(ArrayList<String> fileInput) {
    test = fileInput;
    initialize();
}

/**
 * Initialize the contents of the frame.
 */
private void initialize() {
    frame = new JFrame();
    frame.setIconImage(icon.getImage());
    frame.setTitle("QickSort - Start");
    frame.setResizable(false);
    frame.setBounds(100, 100, 645, 480);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    GridBagLayout gridBagLayout = new GridBagLayout();
    gridBagLayout.columnWidths = new int[]{480, 127, 0};
    gridBagLayout.rowHeights = new int[]{135, 60, 0, 0, 0, 115, 0};
    gridBagLayout.columnWeights = new double[]{1.0, 0.0, Double.MIN_VALUE};
    gridBagLayout.rowWeights = new double[]{0.0, 0.0, 0.0, 0.0, 0.0, 1.0, Double.MIN_VALUE};
    frame.getContentPane().setLayout(gridBagLayout);
    frame.setVisible(true);

    JLabel logo = new JLabel("");
    logo.setIcon(new ImageIcon(MasterWin.class.getResource("/View/Logo.gif")));
    GridBagConstraints gbc_logo = new GridBagConstraints();
    gbc_logo.fill = GridBagConstraints.HORIZONTAL;
    gbc_logo.gridwidth = 2;
    gbc_logo.insets = new Insets(0, 0, 5, 0);
    gbc_logo.anchor = GridBagConstraints.SOUTH;
    gbc_logo.gridx = 0;
    gbc_logo.gridy = 0;
    frame.getContentPane().add(logo, gbc_logo);

    JLabel lblChosePathYou = new JLabel("Choose paths you want to use:");
    GridBagConstraints gbc_lblChosePathYou = new GridBagConstraints();
    gbc_lblChosePathYou.anchor = GridBagConstraints.SOUTHWEST;
    gbc_lblChosePathYou.insets = new Insets(0, 60, 5, 5);
    gbc_lblChosePathYou.gridx = 0;
    gbc_lblChosePathYou.gridy = 1;
    frame.getContentPane().add(lblChosePathYou, gbc_lblChosePathYou);

    txtFieldPath = new JTextField();
    txtFieldPath.setEditable(false);
    GridBagConstraints gbc_txtFieldPath = new GridBagConstraints();
    gbc_txtFieldPath.fill = GridBagConstraints.HORIZONTAL;
    gbc_txtFieldPath.insets = new Insets(0, 60, 5, 5);
    gbc_txtFieldPath.gridx = 0;
    gbc_txtFieldPath.gridy = 2;
    frame.getContentPane().add(txtFieldPath, gbc_txtFieldPath);
    txtFieldPath.setColumns(10);

    btnBrowse = new JButton("Browse...");
    btnBrowse.setMinimumSize(new Dimension(89, 25));
    btnBrowse.setMaximumSize(new Dimension(89, 25));
    GridBagConstraints gbc_btnBrowse = new GridBagConstraints();
    gbc_btnBrowse.anchor = GridBagConstraints.WEST;
    gbc_btnBrowse.insets = new Insets(0, 10, 5, 0);
    gbc_btnBrowse.gridx = 1;
    gbc_btnBrowse.gridy = 2;
    frame.getContentPane().add(btnBrowse, gbc_btnBrowse);

    lblChosenFolderpaths = new JLabel("Chosen folderpaths:");
    GridBagConstraints gbc_lblChosenFolderpaths = new GridBagConstraints();
    gbc_lblChosenFolderpaths.anchor = GridBagConstraints.SOUTHWEST;
    gbc_lblChosenFolderpaths.insets = new Insets(0, 60, 5, 5);
    gbc_lblChosenFolderpaths.gridx = 0;
    gbc_lblChosenFolderpaths.gridy = 3;
    frame.getContentPane().add(lblChosenFolderpaths, gbc_lblChosenFolderpaths);

    btnAddPathTo = new JButton("Add to list");
    GridBagConstraints gbc_btnAddPathTo = new GridBagConstraints();
    gbc_btnAddPathTo.anchor = GridBagConstraints.WEST;
    gbc_btnAddPathTo.insets = new Insets(5, 10, 5, 0);
    gbc_btnAddPathTo.gridx = 1;
    gbc_btnAddPathTo.gridy = 3;
    frame.getContentPane().add(btnAddPathTo, gbc_btnAddPathTo);

    btnRemove = new JButton("Remove");
    btnRemove.setToolTipText("Delete selected path");
    btnRemove.setPreferredSize(new Dimension(89, 25));
    btnRemove.setMinimumSize(new Dimension(89, 25));
    btnRemove.setMaximumSize(new Dimension(89, 25));
    GridBagConstraints gbc_btnRemove = new GridBagConstraints();
    gbc_btnRemove.anchor = GridBagConstraints.NORTHWEST;
    gbc_btnRemove.insets = new Insets(5, 10, 5, 0);
    gbc_btnRemove.gridx = 1;
    gbc_btnRemove.gridy = 4;
    frame.getContentPane().add(btnRemove, gbc_btnRemove);

    btnNext = new JButton("Accept");
    btnNext.setPreferredSize(new Dimension(89, 25));
    btnNext.setMinimumSize(new Dimension(89, 25));
    btnNext.setMaximumSize(new Dimension(89, 25));
    GridBagConstraints gbc_btnNext = new GridBagConstraints();
    gbc_btnNext.anchor = GridBagConstraints.SOUTHWEST;
    gbc_btnNext.insets = new Insets(0, 10, 25, 0);
    gbc_btnNext.gridx = 1;
    gbc_btnNext.gridy = 5;
    frame.getContentPane().add(btnNext, gbc_btnNext);

    scrollPane = new JScrollPane();
    GridBagConstraints gbc_scrollPane = new GridBagConstraints();
    gbc_scrollPane.gridheight = 2;
    gbc_scrollPane.insets = new Insets(0, 60, 25, 5);
    gbc_scrollPane.fill = GridBagConstraints.BOTH;
    gbc_scrollPane.gridx = 0;
    gbc_scrollPane.gridy = 4;
    frame.getContentPane().add(scrollPane, gbc_scrollPane);
//JList I copy the array    
    linkList = new JList(test.toArray());
    scrollPane.setViewportView(linkList);
}

}

问题： 真奇怪啊！有时文本显示在我的JList上 - 但是如果我再次启动程序，那么只有一个没有JList或输入的空ScrollPane。 它或多或少随机出现文本。

我尝试了各种各样的Array（List）来实现。 - 使用AbstractModel（）或者只是toArray（）。总是一样的结果..

有人知道这个问题吗？

Answer 1

变化：

protected static ArrayList<String> input;

要：

protected static final ArrayList<String> input = new ArrayList<String>();

删除main中input的作业。

在invokeLater：

中包含对sw代码的调用

SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            JFrame.setDefaultLookAndFeelDecorated(false);
            MasterWin win = new MasterWin(input);
        };
    });

Answer 2

将列表设置为视口视图后，您应该在invalidate()上调用JList，这将告诉基础Swing图形系统它需要检查组件以及任何可能受影响的组件是否或不是这些需要更新。

不调用repaint()，因为这将触发组件的重新绘制，它不会确保其他受影响的组件也正确更新 - 并且因为这个{ {1}}包含在JList中，它不会按预期运行。

Answer 3

我解决了这个问题：

我踢出Scrollpane并仅使用了JList。但那也不起作用。

我创建JList后现在调用updateUI() - 现在它可以工作。

Answer 4

user268396关于布局验证的答案是正确的，但您首先应该永远不需要处于这种情况。您的布局无效，因为您在 JFrame可见后添加组件。只需将调用移至frame.setVisible(true)到initialize()方法的末尾，您就应该看到问题消失了，因为布局现在已经完成，它将首次验证并正确渲染。