3
아래의 예제 코드에서는 파일 해시를 계산하는 데 사용합니다. 그래서 진행 상황을 보여주는 Jprogressbar를 시작합니다. 그러나 때로는 99 %에서 중지하고 때로는 실행되지 않습니다.JProgressbar는 어떻게 작동해야합니까?
이미 다른 자습서와 코드 예제를 읽었습니다.
구문 오류 또는 다른 것일 수 있습니까? 여기에 당신은 또한 당신의 ProgressBar를 업데이트해야합니다 -
감사
package progressbartest;
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileReader;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JProgressBar;
import javax.swing.JTextField;
import javax.swing.SwingWorker;
public class ProgressBarTest implements ActionListener, PropertyChangeListener{
JFrame f;
JPanel p;
BorderLayout bdl;
JButton cf;
JTextField tf1;
JLabel ls;
JProgressBar progressBar;
JFileChooser fc;
File sf;
FileInputStream fis;
String hexRes1;
String hexRes2 = "";
private Task task;
private int progress;
String selection;
public static void main(String[] args) {
new ProgressBarTest().startApp();// TODO code application logic here
}
private void startApp() {
f = new JFrame();
p = new JPanel();
bdl = new BorderLayout();
cf = new JButton("Check-File");
ls = new JLabel();
tf1 = new JTextField();
progressBar = new JProgressBar(0, 100);
progressBar.setValue(0);
progressBar.setStringPainted(true);
p.setLayout(bdl);
p.add(BorderLayout.NORTH, cf);
p.add(BorderLayout.CENTER, ls);
p.add(BorderLayout.WEST, tf1);
p.add(BorderLayout.SOUTH, progressBar);
fc = new JFileChooser();
cf.addActionListener(this);
f.getContentPane().add(p);
//f.pack();
f.setTitle("ProgressTest");
f.setSize(950,350);
f.setResizable(false);
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
@Override
public void actionPerformed(ActionEvent e) throws NullPointerException {
//System.out.println(javax.swing.SwingUtilities.isEventDispatchThread());
//choose a file when the button cf is clicked
if (e.getSource() == cf) {
int returnVal = fc.showOpenDialog(p);
fc.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES);
if (returnVal == JFileChooser.APPROVE_OPTION)
sf = fc.getSelectedFile();
//empty the values
tf1.setText("");
hexRes2 = "";
//start the task to calculate the file
task = new Task();
task.addPropertyChangeListener(this);
task.execute();
ls.setText("Wait !");
}
}
class Task extends SwingWorker<Void, Void> {
/*
* Main task. Executed in background thread.
*/
@Override
public Void doInBackground() throws InterruptedException, IOException {
//progressbar variables to go thru the file
setProgress(0);
int progress = 0;
BufferedReader br = new BufferedReader(new FileReader(sf));
String line = br.readLine();
long readLength = 0;
long totalLength = sf.length();
double lengthPerPercent = 100.0/totalLength;
//Thread.sleep(1000);
//while the line of the file isn't empty execute
try {
while (line != null) {
//Thread.sleep(100);
fis = new FileInputStream(sf);
//digest calculation
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] b = new byte[1024];
int i;
while((i = fis.read(b)) >= 0) {
md.update(b, 0, i);
} while(i != -1)
fis.close();
byte[] ba = md.digest();
for (int j = 0; j < ba.length; j++) {
hexRes1 = Integer.toHexString((ba[j] & 255) | 256).substring(1);
hexRes2 += hexRes1;
}
// calculate progress.
readLength += line.length();
progress = (int) (lengthPerPercent * readLength);
setProgress(Math.min(progress, 100));
line = br.readLine();
} //printing the value
tf1.setText(hexRes2);
} catch (IOException | NoSuchAlgorithmException ex) {
Logger.getLogger(ProgressBarTest.class.getName()).log(Level.SEVERE, null, ex);
} catch (NullPointerException ex) {f.repaint();
} finally {fis.close();}
return null;
//System.out.println(javax.swing.SwingUtilities.isEventDispatchThread());
}
}
/*
* Executed in event dispatching thread
*/
public void done() {
progressBar.setValue(0);
ls.setText("Done!\n");
}
/**
* Invoked when task's progress property changes.
*/
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getPropertyName().equals("progress")) {
int progress = (Integer) evt.getNewValue();
progressBar.setValue(progress);
}
}
}
같은 파일에서 문제가 발생합니까? –
아니요, 작은 크기에서는 99 %로 멈추고 더 큰 크기는 멈추는 것처럼 보입니다. –