直到代碼完成，JComponent.revalidate（）才會更新

Question

**您好，我正在嘗試用Java創建一個存檔器。 這意味着我一直在從流中讀取和寫入。 我希望能夠更新JProgressBar以顯示我寫了多少。 我的代碼當前在歸檔中的每個條目之后都會更新進度欄。 我的變量和所有內容都表明代碼已更新，但未在屏幕上顯示。 每次進入存檔后，我都在JPanel上調用revalidate（）方法，該方法包含進度條和文本，但是屏幕上沒有任何反應。 在寫入歸檔文件的輸出流完全完成寫入之前，屏幕不會更新。 然后，我在進度文本中看到完整的進度條，其中顯示“已寫入24個文件中的24個”。

誰能告訴我如何在代碼執行完畢之前更新圖形？ 謝謝

這是我的代碼：

WritingBox.java：

package org.apache.commons.compress;
import javax.swing.JDialog;
public class WritingBox extends javax.swing.JDialog {

/** Creates new form WritingBox */
public WritingBox(java.awt.Frame parent, boolean modal) {
    super(parent, modal);
    initComponents();
    theprogressbar.setMaximum(1);
    theprogressbar.setMinimum(0);
    this.setLocation(parent.getLocationOnScreen().x+(parent.getWidth()-this.getWidth())/2, parent.getLocationOnScreen().y+(parent.getHeight()-this.getHeight())/2);
    this.setVisible(true);
}
public void progressListener(Progress p) {
    writtenxoutofx.setText("Written "+Integer.toString(p.doneSoFar)+" out of "+Integer.toString(p.total)+" files to the Archive");
    theprogressbar.setValue(p.doneSoFar/p.total);
    if (p.doneSoFar == p.total) this.setDefaultCloseOperation(JDialog.DISPOSE_ON_CLOSE);
    thecontainer.revalidate();
};
/** This method is called from within the constructor to
 * initialize the form.
 * WARNING: Do NOT modify this code. The content of this method is
 * always regenerated by the Form Editor.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

    thecontainer = new javax.swing.JPanel();
    jLabel1 = new javax.swing.JLabel();
    writtenxoutofx = new javax.swing.JLabel();
    theprogressbar = new javax.swing.JProgressBar();

    setDefaultCloseOperation(javax.swing.WindowConstants.DO_NOTHING_ON_CLOSE);
    setName("Form"); // NOI18N

    thecontainer.setName("thecontainer"); // NOI18N

    org.jdesktop.application.ResourceMap resourceMap = org.jdesktop.application.Application.getInstance(targzipmanager.TarGzipManagerApp.class).getContext().getResourceMap(WritingBox.class);
    jLabel1.setText(resourceMap.getString("jLabel1.text")); // NOI18N
    jLabel1.setName("jLabel1"); // NOI18N

    writtenxoutofx.setText(resourceMap.getString("writtenxoutofx.text")); // NOI18N
    writtenxoutofx.setName("writtenxoutofx"); // NOI18N

    theprogressbar.setName("theprogressbar"); // NOI18N

    javax.swing.GroupLayout thecontainerLayout = new javax.swing.GroupLayout(thecontainer);
    thecontainer.setLayout(thecontainerLayout);
    thecontainerLayout.setHorizontalGroup(
        thecontainerLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(thecontainerLayout.createSequentialGroup()
            .addContainerGap()
            .addGroup(thecontainerLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addComponent(theprogressbar, javax.swing.GroupLayout.DEFAULT_SIZE, 307, Short.MAX_VALUE)
                .addComponent(jLabel1)
                .addComponent(writtenxoutofx))
            .addContainerGap())
    );
    thecontainerLayout.setVerticalGroup(
        thecontainerLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(thecontainerLayout.createSequentialGroup()
            .addContainerGap()
            .addComponent(jLabel1)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(writtenxoutofx)
            .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
            .addComponent(theprogressbar, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
            .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
    );

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(thecontainer, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(thecontainer, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );

    pack();
}// </editor-fold>

// Variables declaration - do not modify
private javax.swing.JLabel jLabel1;
private javax.swing.JPanel thecontainer;
private javax.swing.JProgressBar theprogressbar;
private javax.swing.JLabel writtenxoutofx;
// End of variables declaration

}

Progress.java

package org.apache.commons.compress;

public class Progress { //This is basically a Struct
public int total;
public int doneSoFar;
private Progress (){

}
public Progress(int d, int t){
    total = t;
    doneSoFar = t;
}
}

TarArchive.java：d​​oSave方法

public void doSave(OutputStream output) throws ArchiveException {
        // Stream initializing
        //BufferedInputStream origin = null;

        //out.setMethod(ZipOutputStream.DEFLATED);
        //byte data[] = new byte[BUFFER];

        // get a list of files from current directory
        // less than one file leads to an exception
        Iterator iterator = this.getEntryIterator();
        if(!iterator.hasNext()) {
              throw new ArchiveException("There must be at least one file to be pack.");
        }
        JFrame jf = targzipmanager.TarGzipManagerApp.getApplication().getMainFrame();
        WritingBox wb = new WritingBox(jf, false);
        TarOutputStream out = null;
        int x = 0;
        try {
              out = new TarOutputStream(new BufferedOutputStream(output));
              while(iterator.hasNext()) {
                    x++;
                    ArchiveEntry archiveEntry = (ArchiveEntry)iterator.next();
                    InputStream fInputStream = archiveEntry.getStream();

                    TarEntry entry = new TarEntry(archiveEntry.getName());
                    entry.setModTime( 0 );
                entry.setSize( fInputStream.available() );
                entry.setUserID( 0 );
                entry.setGroupID( 0 );
                entry.setUserName( "avalon" );
                entry.setGroupName( "excalibur" );
                entry.setMode( 0100000 );
                out.putNextEntry( entry );
                out.copyEntryContents( fInputStream );
                out.closeEntry();
                wb.progressListener(new Progress(x, entries.size()));
              }
        } catch (IOException e) {
              throw new ArchiveException("Creation of this archive failed cause of IOExceptions.", e);
        } finally {
              try {
                    out.close();
              } catch (IOException e1) {
                    throw new ArchiveException("Creation of this archive failed cause of IOExceptions.", e1);
              }
        }
  }

誰能幫我？ 即使我在每個條目之后都調用revalidate（），它僅在代碼停止並開始等待時才更新。 **

Answer 1

聽起來您正在執行AWT事件調度線程（EDT）上的文件I / O。 這會阻止所有重繪或事件處理。 在其他線程上運行I / O，並通過java.awt.EventQueue.invokeLater更新GUI。