Java SWT ProgressBar Tutorial

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1- SWT ProgressBar

ProgressBar is UI control that visualize progress of any operations in your SWT applications.
The figure below illustrates 3 ProgressBars, 2 first ProgressBars describe the progress of work with a definite volume. The last one describes the progress of work with indefinite volume.
Vertical ProgressBar:
The styles can be applied to ProgressBar:
  • SMOOTH
  • HORIZONTAL
  • VERTICAL
  • INDETERMINATE
// Horizontal ProgressBar
ProgressBar progressBar1 = new ProgressBar(shell, SWT.NULL);
ProgressBar progressBar2 = new ProgressBar(shell, SWT.SMOOTH);
ProgressBar progressBar3 = new ProgressBar(shell, SWT.INDETERMINATE);


// Vertical ProgressBar
ProgressBar progressBar4 = new ProgressBar(shell, SWT.VERTICAL | SWT.SMOOTH);

2- SWT ProgressBar Example

For example. Create ProgressBars with different styles:
ProgressDemo.java
package org.o7planning.swt.progressbar;

import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.ProgressBar;
import org.eclipse.swt.widgets.Shell;

public class ProgressBarDemo {

    public ProgressBarDemo() {

        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setText("SWT ProgressBar (o7planning.org)");
        shell.setSize(450, 200);

        ProgressBar progressBar1 = new ProgressBar(shell, SWT.NULL);
        ProgressBar progressBar2 = new ProgressBar(shell, SWT.SMOOTH);
        ProgressBar progressBar3 = new ProgressBar(shell, SWT.INDETERMINATE);

        progressBar1.setMinimum(30);
        progressBar1.setMaximum(250);
        progressBar1.setSelection(160);
        
        progressBar2.setMinimum(30);
        progressBar2.setMaximum(250);
        progressBar2.setSelection(200);        

        progressBar1.setBounds(140, 10, 200, 20);
        progressBar2.setBounds(140, 40, 200, 20);
        progressBar3.setBounds(140, 70, 200, 20);

        Label label1 = new Label(shell, SWT.NULL);
        label1.setText("(default)");
        Label label2 = new Label(shell, SWT.NULL);
        label2.setText("SWT.SMOOTH");
        Label label3 = new Label(shell, SWT.NULL);
        label3.setText("SWT.INDETERMINATE");

        label1.setAlignment(SWT.RIGHT);
        label2.setAlignment(SWT.RIGHT);
        label3.setAlignment(SWT.RIGHT);

        label1.setBounds(10, 10, 120, 20);
        label2.setBounds(10, 40, 120, 20);
        label3.setBounds(10, 70, 120, 20);
 
        shell.open();

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }

        display.dispose();
    }

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

3- ProgressBar and Thread

You can create a Thread object to perform certain task, such as copying files list. Copying requires take some time, you need to use ProgressBar to display the percentage of work already done.
ProgressBarCopyDemo.java
package org.o7planning.swt.progressbar;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.ProgressBar;
import org.eclipse.swt.widgets.Shell;

public class ProgressBarCopyDemo {

    private CopyThread copyThread = null;

    public ProgressBarCopyDemo() {

        Display display = new Display();
        Shell shell = new Shell(display);
        shell.setText("SWT ProgressBar (o7planning.org)");
        shell.setSize(450, 200);

        shell.setLayout(null);

        ProgressBar progressBar = new ProgressBar(shell, SWT.NONE);
        progressBar.setBounds(10, 23, 350, 17);

        Label labelInfo = new Label(shell, SWT.NONE);
        labelInfo.setBounds(10, 46, 350, 15);
        labelInfo.setText(" ...");

        // Button Copy
        Button buttonCopy = new Button(shell, SWT.NONE);
        buttonCopy.setBounds(122, 67, 75, 25);
        buttonCopy.setText("Copy");

        // Button Cancel
        Button buttonCancel = new Button(shell, SWT.NONE);
        buttonCancel.setBounds(200, 67, 75, 25);
        buttonCancel.setText("Cancel");
        buttonCancel.setEnabled(false);

        buttonCopy.addSelectionListener(new SelectionAdapter() {

            @Override
            public void widgetSelected(SelectionEvent e) {
                copyThread = new CopyThread(display, progressBar, labelInfo, buttonCopy, buttonCancel);
                copyThread.start();
            }
        });

        buttonCancel.addSelectionListener(new SelectionAdapter() {

            @Override
            public void widgetSelected(SelectionEvent e) {
                if (copyThread != null) {
                    copyThread.cancel();
                }
            }
        });

        shell.open();

        while (!shell.isDisposed()) {
            if (!display.readAndDispatch()) {
                display.sleep();
            }
        }

        display.dispose();
    }

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

}
CopyThread.java
package org.o7planning.swt.progressbar;

import java.io.File;

import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.ProgressBar;

public class CopyThread extends Thread {

    private Display display;
    private ProgressBar progressBar;
    private Button buttonCopy;
    private Button buttonCancel;
    private Label labelInfo;
    private boolean cancel;

    public CopyThread(Display display, ProgressBar progressBar, //
            Label labelInfo, Button buttonCopy, Button buttonCancel) {
        this.display = display;
        this.progressBar = progressBar;
        this.buttonCopy = buttonCopy;
        this.buttonCancel = buttonCancel;
        this.labelInfo = labelInfo;
    }

    @Override
    public void run() {
        if (display.isDisposed()) {
            return;
        }
        this.updateGUIWhenStart();

        // Copy All file In C:/Windows
        File dir = new File("C:/Windows");
        File[] files = dir.listFiles();
        int count = files.length;

        int i = 0;
        for (File file : files) {
            if (cancel) {
                break;
            }
            i++;
            if (file.isFile()) {
                this.copy(file);
            } else {
                continue;
            }
            this.updateGUIInProgress(file, i, count);
        }
        //
        this.updateGUIWhenFinish();
    }

    private void copy(File file) {
        try {
            Thread.sleep(500);
        } catch (InterruptedException e) {
        }
    }

    private void updateGUIWhenStart() {
        display.asyncExec(new Runnable() {

            @Override
            public void run() {
                buttonCopy.setEnabled(false);
                buttonCancel.setEnabled(true);
            }
        });
    }

    private void updateGUIWhenFinish() {
        display.asyncExec(new Runnable() {

            @Override
            public void run() {
                buttonCopy.setEnabled(true);
                buttonCancel.setEnabled(false);
                progressBar.setSelection(0);
                progressBar.setMaximum(1);
                if (cancel) {
                    labelInfo.setText("Cancelled!");
                } else {
                    labelInfo.setText("Finished!");
                }
            }
        });
    }

    private void updateGUIInProgress(File file, int value, int count) {
        display.asyncExec(new Runnable() {

            @Override
            public void run() {
                labelInfo.setText("Copying file: " + file.getAbsolutePath());
                progressBar.setMaximum(count);
                progressBar.setSelection(value);
            }
        });
    }

    public void cancel() {
        this.cancel = true;
    }

}

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