Eclipse allows to use dialogs to prompt the user for additional information or provide the user with feedback. The Eclipse platform offers several standard dialogs via SWT and JFace.

SWT offers an API for the use of the native dialogs from the OS platform. The SWT dialogs are the following:

The following example shows how to use the MessageBox class to open a message dialog.

// create dialog with ok and cancel button and info icon
MessageBox dialog = 
  new MessageBox(shell, SWT.ICON_QUESTION | SWT.OK| SWT.CANCEL);
dialog.setText("My info");
dialog.setMessage("Do you really want to do this?");

# open dialog and wait for user selection
returnCode = dialog.open(); 

Eclipse provides several standard selection Dialogs in Eclipse 3.x. In Eclipse 3.x you can directly use them, in Eclipse 4.x you may have to copy them into your plug-in and modify them slightly. I still list them here, so that you can use their coding as examples.

A release after Eclipse 4.2 might make the dialogs directly available again.

Here is a list of these Dialogs.

For example ElementListSelectionDialog allows you to select elements from a list where the dialog provides a filter for the elements.

ElementListSelectionDialog dialog = 
  new ElementListSelectionDialog(shell, new LabelProvider());
dialog.setElements(new String[] { "Linux", "Mac", "Windows" });
dialog.setTitle("Which operating system are you using");
// User pressed cancel
if (dialog.open() != Window.OK) {
    return false;
}
Object[] result = dialog.getResult(); 

This tutorial assumes what you have basic understanding of development for the Eclipse platform. Please see Eclipse RCP Tutorial or Eclipse Plug-in Tutorial if you need any basic information.

The following demonstrates how to use the SWT Dialogs in an Eclipse application. We will use a Button in the view to call the SWT Dialogs.

Create a new Eclipse plug-in project called "de.vogella.rcp.dialogs.swt" with one Part (View). Create the following composite.

package de.vogella.rcp.dialogs.swt;

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.ColorDialog;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.DirectoryDialog;
import org.eclipse.swt.widgets.FileDialog;
import org.eclipse.swt.widgets.FontDialog;
import org.eclipse.swt.widgets.MessageBox;
import org.eclipse.swt.widgets.Shell;

public class MyComposite extends Composite {

  public MyComposite(final Composite parent, int style) {
    super(parent, style);
    Button button = new Button(parent, SWT.PUSH);
    button.setText("Press me");
    button.addSelectionListener(new SelectionAdapter() {
      @Override
      public void widgetSelected(SelectionEvent e) {
        Shell shell = parent.getShell();
        openDialogs(shell);
      }
    });

  }

  private void openDialogs(Shell shell) {
    // File standard dialog
    FileDialog fileDialog = new FileDialog(shell);
    // Set the text
    fileDialog.setText("Select File");
    // Set filter on .txt files
    fileDialog.setFilterExtensions(new String[] { "*.txt" });
    // Put in a readable name for the filter
    fileDialog.setFilterNames(new String[] { "Textfiles(*.txt)" });
    // Open Dialog and save result of selection
    String selected = fileDialog.open();
    System.out.println(selected);

    // Directly standard selection
    DirectoryDialog dirDialog = new DirectoryDialog(shell);
    dirDialog.setText("Select your home directory");
    String selectedDir = dirDialog.open();
    System.out.println(selectedDir);

    // Select Font
    FontDialog fontDialog = new FontDialog(shell);
    fontDialog.setText("Select your favorite font");
    FontData selectedFont = fontDialog.open();
    System.out.println(selectedFont);

    // Select Color
    ColorDialog colorDialog = new ColorDialog(shell);
    colorDialog.setText("Select your favorite color");
    RGB selectedColor = colorDialog.open();
    System.out.println(selectedColor);

    // Message
    MessageBox messageDialog = new MessageBox(shell, SWT.ERROR);
    messageDialog.setText("Evil Error has happend");
    messageDialog.setMessage("This is fatal!!!");
    int returnCode = messageDialog.open();
    System.out.println(returnCode);

    // Message with ok and cancel button and info icon
    messageDialog = new MessageBox(shell, 
        SWT.ICON_QUESTION | 
        SWT.OK
        | SWT.CANCEL);
    messageDialog.setText("My info");
    messageDialog.setMessage("Do you really want to do this.");
    returnCode = messageDialog.open();
    System.out.println(returnCode);
  }

} 

In the method which creates your user interface, add this composite to your Part via:

new MyComposite(parent, SWT.NONE); 

Run the application. If you select your button the Dialogs will be displayed.

Create a new class called PasswordDialog which extends the Dialog class. This dialog should allow to enter a user name and a password.

package com.example.e4.rcp.todo.dialogs;

import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.SWT;
import org.eclipse.swt.widgets.Text;
import org.eclipse.swt.layout.GridData;

public class PasswordDialog extends Dialog {
  private Text userText;
  private Text passwordText;
  private String user="";
  private String password="";

  
/**
   * Create the dialog.
   * 
   * @param parentShell
   */
  public PasswordDialog(Shell parentShell) {
    super(parentShell);
  }

  
/**
   * Create contents of the dialog.
   * 
   * @param parent
   */
  @Override
  protected Control createDialogArea(Composite parent) {
    Composite container = (Composite) super.createDialogArea(parent);
    GridLayout gl_container = new GridLayout(2, false);
    gl_container.marginRight = 5;
    gl_container.marginLeft = 10;
    container.setLayout(gl_container);

    Label lblUser = new Label(container, SWT.NONE);
    lblUser.setText("User:");

    userText = new Text(container, SWT.BORDER);
    userText.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false,
        1, 1));
    userText.setText(user);

    Label lblNewLabel = new Label(container, SWT.NONE);
    GridData gd_lblNewLabel = new GridData(SWT.LEFT, SWT.CENTER, false,
        false, 1, 1);
    gd_lblNewLabel.horizontalIndent = 1;
    lblNewLabel.setLayoutData(gd_lblNewLabel);
    lblNewLabel.setText("Password:");

    passwordText = new Text(container, SWT.BORDER);
    passwordText.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true,
        false, 1, 1));
    passwordText.setText(password);
    return container;
  }

  
/**
   * Create contents of the button bar.
   * 
   * @param parent
   */
  @Override
  protected void createButtonsForButtonBar(Composite parent) {
    createButton(parent, IDialogConstants.OK_ID, IDialogConstants.OK_LABEL,
        true);
    createButton(parent, IDialogConstants.CANCEL_ID,
        IDialogConstants.CANCEL_LABEL, false);
  }

  
/**
   * Return the initial size of the dialog.
   */
  @Override
  protected Point getInitialSize() {
    return new Point(450, 300);
  }

  @Override
  protected void okPressed() {
    user = userText.getText();
    password = passwordText.getText();

    super.okPressed();
  }

  public String getUser() {
    return user;
  }

  public void setUser(String user) {
    this.user = user;
  }

  public String getPassword() {
    return password;
  }

  public void setPassword(String password) {
    this.password = password;
  }

} 

To use the dialog in your application, create a menu entry (and a command with a handler) which allows you to open this dialog. The class associated with the handler should be called EnterCredentialsHandler.

package com.example.e4.rcp.todo.handlers;

import javax.inject.Inject;

import org.eclipse.core.runtime.preferences.IEclipsePreferences;
import org.eclipse.e4.core.di.annotations.Execute;
import org.eclipse.e4.core.di.extensions.Preference;
import org.eclipse.jface.window.Window;
import org.eclipse.swt.widgets.Shell;

import com.example.e4.rcp.todo.dialogs.PasswordDialog;

public class EnterCredentialsHandler {
  
  @Execute
  public void execute(Shell shell) {
    PasswordDialog dialog = new PasswordDialog(shell);
    
    // Get the new values from the dialog
    if (dialog.open() == Window.OK) {
      //TODO do something with the values
    }
  }
  
} 

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