我正在尝试创建一个按钮，按下该按钮后，将在 JTextArea 中显示文本，并在等待一段时间后每次运行循环中的步骤时不断更新。我现在的代码打印出循环第一步的样子，然后停止。我所指的操作位于 //Actions 下的底部。
public class MainWindow {
private JFrame frmMcakennaAntivirus;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
MainWindow window = new MainWindow();
window.frmMcakennaAntivirus.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public MainWindow() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frmMcakennaAntivirus = new JFrame();
frmMcakennaAntivirus.setResizable(false);
frmMcakennaAntivirus.setTitle("McAkenna Anti-Virus");
frmMcakennaAntivirus.setAlwaysOnTop(true);
frmMcakennaAntivirus.setBounds(100, 100, 303, 197);
frmMcakennaAntivirus.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GridBagLayout gridBagLayout = new GridBagLayout();
gridBagLayout.columnWidths = new int[]{0, 149, 135, 0, 0};
gridBagLayout.rowHeights = new int[]{0, 14, 0, 24, 45, 0, 0};
gridBagLayout.columnWeights = new double[]{0.0, 0.0, 0.0, 0.0, Double.MIN_VALUE};
gridBagLayout.rowWeights = new double[]{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, Double.MIN_VALUE};
frmMcakennaAntivirus.getContentPane().setLayout(gridBagLayout);
JSeparator separator = new JSeparator();
GridBagConstraints gbc_separator = new GridBagConstraints();
gbc_separator.insets = new Insets(0, 0, 5, 5);
gbc_separator.gridx = 1;
gbc_separator.gridy = 0;
frmMcakennaAntivirus.getContentPane().add(separator, gbc_separator);
JSeparator separator_1 = new JSeparator();
GridBagConstraints gbc_separator_1 = new GridBagConstraints();
gbc_separator_1.insets = new Insets(0, 0, 5, 5);
gbc_separator_1.gridx = 0;
gbc_separator_1.gridy = 1;
frmMcakennaAntivirus.getContentPane().add(separator_1, gbc_separator_1);
JButton btnBeginScan = new JButton("Begin Scan");
btnBeginScan.setFont(new Font("Tahoma", Font.BOLD, 11));
btnBeginScan.setForeground(new Color(0, 0, 0));
btnBeginScan.setBackground(new Color(124, 252, 0));
GridBagConstraints gbc_btnBeginScan = new GridBagConstraints();
gbc_btnBeginScan.insets = new Insets(0, 0, 5, 5);
gbc_btnBeginScan.gridx = 1;
gbc_btnBeginScan.gridy = 1;
frmMcakennaAntivirus.getContentPane().add(btnBeginScan, gbc_btnBeginScan);
JButton btnFixProblems = new JButton("Fix Problems");
btnFixProblems.setBackground(new Color(127, 255, 0));
GridBagConstraints gbc_btnFixProblems = new GridBagConstraints();
gbc_btnFixProblems.insets = new Insets(0, 0, 5, 5);
gbc_btnFixProblems.gridx = 2;
gbc_btnFixProblems.gridy = 1;
frmMcakennaAntivirus.getContentPane().add(btnFixProblems, gbc_btnFixProblems);
JSeparator separator_2 = new JSeparator();
GridBagConstraints gbc_separator_2 = new GridBagConstraints();
gbc_separator_2.insets = new Insets(0, 0, 5, 0);
gbc_separator_2.gridx = 3;
gbc_separator_2.gridy = 1;
frmMcakennaAntivirus.getContentPane().add(separator_2, gbc_separator_2);
Choice choice = new Choice();
choice.setBackground(SystemColor.scrollbar);
GridBagConstraints gbc_choice = new GridBagConstraints();
gbc_choice.insets = new Insets(0, 0, 5, 5);
gbc_choice.fill = GridBagConstraints.HORIZONTAL;
gbc_choice.gridx = 1;
gbc_choice.gridy = 2;
frmMcakennaAntivirus.getContentPane().add(choice, gbc_choice);
choice.add("Full System Scan");
choice.add("Quick Scan");
JProgressBar progressBar = new JProgressBar();
GridBagConstraints gbc_progressBar = new GridBagConstraints();
gbc_progressBar.fill = GridBagConstraints.BOTH;
gbc_progressBar.insets = new Insets(0, 0, 5, 5);
gbc_progressBar.gridx = 1;
gbc_progressBar.gridy = 3;
frmMcakennaAntivirus.getContentPane().add(progressBar, gbc_progressBar);
final JTextArea textArea = new JTextArea();
textArea.setLineWrap(true);
textArea.setFont(new Font("Source Sans Pro Light", Font.PLAIN, 12));
textArea.setEditable(false);
textArea.setBackground(SystemColor.inactiveCaption);
GridBagConstraints gbc_textArea = new GridBagConstraints();
gbc_textArea.insets = new Insets(0, 0, 5, 5);
gbc_textArea.fill = GridBagConstraints.BOTH;
gbc_textArea.gridx = 1;
gbc_textArea.gridy = 4;
frmMcakennaAntivirus.getContentPane().add(textArea, gbc_textArea);
JButton btnCancelScan = new JButton("Cancel Scan");
btnCancelScan.setBackground(new Color(255, 0, 0));
GridBagConstraints gbc_btnCancelScan = new GridBagConstraints();
gbc_btnCancelScan.insets = new Insets(0, 0, 0, 5);
gbc_btnCancelScan.gridx = 1;
gbc_btnCancelScan.gridy = 5;
frmMcakennaAntivirus.getContentPane().add(btnCancelScan, gbc_btnCancelScan);
//Actions
btnBeginScan.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
for (int x= 1; x < 6735; x++){
textArea.setText("Files scanned: " + x + "\nViruses found: " + x/350);
try {
Thread.sleep(randInt(90, 200));
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
});
}
public static int randInt(int min, int max) {
Random rand = null;
int randomNum = rand.nextInt((max - min) + 1) + min;
return randomNum;
}
}
最佳答案
您正在阻塞事件调度线程，该线程负责处理重绘请求等。
Swing 是单线程框架，您永远不应该在 EDT 上下文中运行长时间运行或阻塞操作。
参见Concurrency in Swing了解更多详情
改用 SwingWorker 或 Swing Timer。
参见Worker Threads and SwingWorker和 How to use Swing Timers了解更多详情
顺便说一句，您还会遇到 NullPointerException...
Random rand = null;
int randomNum = rand.nextInt((max - min) + 1) + min;
使用Random时，您应该创建一个实例并在需要时重复使用。这将确保您从中获得的值被正确(尽可能)随机化，否则您可能会在很短的时间内得到重复的值
关于java - 在 ActionListener 中持续设置 JTextArea 文本，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/33323154/