Java 框架在 while 循环期间无法正确显示

Question

这是我在使用 jFrame 时遇到的一个严重问题。我有一个“主框架”，一切都是从那里完成的，但是我有另一个框架，里面有一个 gif 图像（正在加载，那个圆圈转来转去），它用作启动画面，上面写着“正在处理，请稍候” ，但是当我拉过那个框架并且我的 while 循环运行时，框架变为空白，直到循环之后才显示任何内容。

我假设这是由于 while 循环消耗计算机资源并“阻止”任何其他进程运行。

请告诉我应该怎么做。

声明新框架的代码是标准的，但我还是会在下面发布。

Processing nc = new Processing();
nc.setVisible(true);

这是我的完整代码，因此您可以看到我试图实现的目标：

第 1 帧的代码（Excel 提取器）：

Processing nc = new Processing();
    nc.setVisible(true);

    JFileChooser chooser = new JFileChooser();
    chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
    int option = chooser.showOpenDialog(this); // parentComponent must a component like JFrame, JDialog...
    if (option == JFileChooser.APPROVE_OPTION) {
    File selectedFile = chooser.getSelectedFile();
     directory = selectedFile.getAbsolutePath();
     System.out.println(directory);

    }


   //create a input stream for your excel file from which data will be read. 
   DateFormat dateFormat = new SimpleDateFormat("yyyy_MM_dd");
   SimpleDateFormat sdf = new SimpleDateFormat("HHmmss");
   String curdate = dateFormat.format(new Date());
   Calendar cal = Calendar.getInstance();
   cal.getTime();
   String curtime = sdf.format(cal.getTime());
try{

FileInputStream excelSheetInput = new FileInputStream(path);
//POIFSFileSystem myFileSystem = new POIFSFileSystem(excelSheetInput);
    XSSFWorkbook myWorkBook = new XSSFWorkbook(excelSheetInput);
    //get first work sheet in your excel file.
    Sheet sheet = myWorkBook.getSheetAt(0);
    //we will read data in first rows(0) second column(1)
    Iterator<Row> rowIterator = sheet.iterator();
    Row myRow1 = sheet.getRow(0);
    Cell myCell1 = myRow1.getCell(0);
    String header="";
    Iterator<Cell> cellIterator1 = myRow1.cellIterator();
    int rowCount = 0;

    while(cellIterator1.hasNext()) {

                            Cell cell1 = cellIterator1.next();

                            switch(cell1.getCellType()) {
                                case Cell.CELL_TYPE_BOOLEAN:
                                    header = header + "\""+cell1.getBooleanCellValue()+"\"" + ",";
                                    break;
                                case Cell.CELL_TYPE_NUMERIC:
                                    cell1.setCellType(Cell.CELL_TYPE_STRING);
                                     header = header + "\""+cell1.getStringCellValue()+"\""+",";
                                    //System.out.print(cell.getStringCellValue() + "\t\t");
                                    break;
                                case Cell.CELL_TYPE_STRING:
                                    header = header + "\""+cell1.getStringCellValue()+"\""+",";
                                    //System.out.print(cell.getStringCellValue() + "\t\t");
                                    break;
                            }
    }

    Row myRow = sheet.getRow(1);
    Cell myCell= myRow.getCell(0);
    Iterator<Cell> cellIterator;
    String firstCell = myCell.getStringCellValue();
    int count =1;
    String nextCell;
    String Matter = "Matter Number: "+firstCell;
    String num = firstCell;
    System.out.println(Matter);
    fWriter = new FileWriter(new File(directory, num+"_"+curdate+"_"+curtime+".csv"));
    writer = new BufferedWriter(fWriter);
    writer.write(Matter);
    writer.newLine();
    writer.write(header);
    writer.newLine();
    String temp;
    while(rowIterator.hasNext())
    {


        //temp = "" + rowCount;
        //jLabel5.setText(temp);
        myRow = sheet.getRow(count);
        cellIterator = myRow.cellIterator();
        Cell myCell2 = myRow.getCell(0);
        nextCell= myCell2.getStringCellValue();


        if(nextCell.equals(firstCell))
        {

            while(cellIterator.hasNext()) {

                            Cell cell = cellIterator.next();

                            switch(cell.getCellType()) {
                                case Cell.CELL_TYPE_BOOLEAN:
                                    System.out.print(cell.getBooleanCellValue() + "\t\t");
                                    break;
                                case Cell.CELL_TYPE_NUMERIC:
                                    cell.setCellType(Cell.CELL_TYPE_STRING);

                                     System.out.print(cell.getStringCellValue()+",");

                                    //System.out.print(cell.getStringCellValue() + "\t\t");
                                    writer.write(cell.getStringCellValue()+",");
                                    break;
                                case Cell.CELL_TYPE_STRING:
                                    System.out.print(cell.getStringCellValue()+",");
                                    //System.out.print(cell.getStringCellValue() + "\t\t");
                                    writer.write(cell.getStringCellValue()+",");
                                    break;
                            }
                        }
            System.out.println();
            writer.newLine();
            count++;
            rowCount++;



        }
        else
        {          

            writer.close();
            myRow = sheet.getRow(count);
            myCell2= myRow.getCell(0);
            nextCell=myCell2.getStringCellValue();
            firstCell=nextCell;
            Matter = "Matter Number: "+firstCell;
            num = firstCell;
            System.out.println(Matter);
            fWriter = new FileWriter(new File(directory, num+"_"+curdate+"_"+curtime+".csv"));
            writer = new BufferedWriter(fWriter);
            writer.write(Matter);
            writer.newLine();
            writer.write(header);
            writer.newLine();
        }


    }
}
catch (Exception e)
{
}

  try {
    nc.dispose();
    writer.close();
} catch (IOException ex) {
    Logger.getLogger(FileChooser.class.getName()).log(Level.SEVERE, null, ex);
}
}

第二帧代码（处理）：

private void initComponents() {

    jLabel1 = new javax.swing.JLabel();
    jLabel2 = new javax.swing.JLabel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    jLabel1.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N
    jLabel1.setText("Processing, Please Wait...");

    jLabel2.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
    jLabel2.setIcon(new javax.swing.ImageIcon(getClass().getResource("/loading.gif"))); // NOI18N

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jLabel1)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        .addComponent(jLabel2, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jLabel1)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
            .addComponent(jLabel2)
            .addContainerGap())
    );

    pack();
}

Answer 1

在不完全了解您要做什么的情况下，您不可能完全得到准确的答案。

从您尝试在事件调度线程的上下文中运行长时间运行的任务的声音来看。该线程负责处理重绘请求等。

阻塞这个线程，防止 Swing 重新绘制自己。

据我所知，您想使用SwingWorker。这将允许您在后台线程中执行您的工作，同时将更新重新同步回 EDT

更新示例

我知道你说过“不想”使用SwingWorker，但老实说，它只是更简单、更安全......

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingWorker;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class LongRunningTask {

    public static void main(String[] args) {
        new LongRunningTask();
    }

    public LongRunningTask() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                new BackgroundWorker().start();

            }
        });
    }

    public class BackgroundWorker extends SwingWorker<Object, Object> {

        private JFrame frame;

        public BackgroundWorker() {
        }

        // Cause exeute is final :P
        public void start() {
            ImageIcon icon = new ImageIcon(getClass().getResource("/spinner.gif"));
            JLabel label = new JLabel("This might take some time");
            label.setIcon(icon);

            frame = new JFrame("Testing");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setLayout(new GridBagLayout());
            frame.add(label);
            frame.pack();
            frame.setLocationRelativeTo(null);
            frame.setVisible(true);

            execute();
        }

        @Override
        protected Object doInBackground() throws Exception {

            System.out.println("Working hard...");
            Thread.sleep(1000 + (((int)Math.round(Math.random() * 5)) * 1000));
            System.out.println("Or hardly working...");

            return null;

        }

        @Override
        protected void done() {
            frame.dispose();
        }

    }
}

Answer 2

您使用 java.util 包中的 Timer 类并安排 timertask 在大约 2 分钟或任务完成后关闭启动屏幕。

 final Processing nc = new Processing();
 nc.setVisible(true);
 Timer timer = new Timer():
 TimerTask task = new TimerTask() {
      public void run() { 
          nc.setVisible( false );
          // to do disposing nc
      }
 };
 timer.schedule( task, 1000 * 3 ); // dispose the processing frame after 3 minutes