Dialog

10.1. Overview

Eclipse supports several predefined dialogs. For example

• org.eclipse.swt.widgets.FileDialog

• org.eclipse.swt.widgets.DirectoryDialog

• org.eclipse.swt.widgets.MessageDialog

• org.eclipse.jface.dialogs.ErrorDialog

Eclipse supports also user defined dialogs. Usually the class TitleAreaDialog is then extended.

10.2. Using standard dialogs

The following will describe how to use standard dialogs.

Create a new project "de.vogella.rcp.intro.dialogs.standard". Use the "Hello RCP" as a template.

Add one command "de.vogella.rcp.intro.dialogs.standard.openDialog" and create the default handler "de.vogella.rcp.intro.dialogs.standard.handler.OpenDialog" for the command. Add the command to the menu.

Define the following code for the default handler.

    
package de.vogella.rcp.intro.dialogs.standard.handler;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.widgets.ColorDialog;
import org.eclipse.swt.widgets.DirectoryDialog;
import org.eclipse.swt.widgets.FileDialog;
import org.eclipse.swt.widgets.FontDialog;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.handlers.HandlerUtil;

public class OpenDialog extends AbstractHandler {

 @Override
 public Object execute(ExecutionEvent event) throws ExecutionException {
  Shell shell = HandlerUtil.getActiveWorkbenchWindow(event).getShell();

  // 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);

  // Now a few messages
  MessageDialog.openConfirm(shell, "Confirm", "Please confirm");
  MessageDialog.openError(shell, "Error", "Error occured");
  MessageDialog.openInformation(shell, "Info", "Info for you");
  MessageDialog.openQuestion(shell, "Question", "Really, really?");
  MessageDialog.openWarning(shell, "Warning", "I warn you");

  return null;
 }

}

   

Run the application. If you select your command the dialogs will be called after each other.

10.3. Selection

Eclipse provides the ElementListSelectionDialog which allows to select elements from a list.

Create a new project "de.vogella.rcp.intro.dialogs.selection". Use the "Hello RCP" as a template.

Add one command "de.vogella.rcp.intro.dialogs.selection.selectionDialog" and create the default handler "de.vogella.rcp.intro.dialogs.selection.handler.SelectionDialog" for the command. Add the command to the menu.

Define the following code in your handler.

    
package de.vogella.rcp.intro.dialogs.selection.handler;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.dialogs.ElementListSelectionDialog;
import org.eclipse.ui.handlers.HandlerUtil;

public class SelectionDialog extends AbstractHandler {

 private Object[] result;

 @Override
 public Object execute(ExecutionEvent event) throws ExecutionException {
  Shell shell = HandlerUtil.getActiveWorkbenchWindow(event).getShell();
  ElementListSelectionDialog dialog = new ElementListSelectionDialog(
    shell, new LabelProvider());
  dialog.setElements(new String[] { "Linux", "Mac", "Windows" });
  dialog.setTitle("Which operating system are you using");
  dialog.open();
  result = dialog.getResult();
  for (Object s : result) {
   System.out.println(s.toString());
  }
  return null;
 }
}

   

Run the application. If you select your command then the dialog will be displayed.

10.4. User defined dialogs

You can also define your own dialogs. Create a new project "de.vogella.rcp.intro.dialogs.custom". Use the "Hello RCP" as a template.

Create the following class MyDialog.

    
package de.vogella.rcp.intro.dialogs.custom.dialogs;

import org.eclipse.jface.dialogs.IMessageProvider;
import org.eclipse.jface.dialogs.TitleAreaDialog;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;

public class MyDialog extends TitleAreaDialog {

 private Text firstNameText;
 private Text lastNameText;
 private String firstName;
 private String lastName;

 public MyDialog(Shell parentShell) {
  super(parentShell);
 }

 @Override
 public void create() {
  super.create();
  // Set the title
  setTitle("This is my first own dialog");
  // Set the message
  setMessage("This is a TitleAreaDialog", IMessageProvider.INFORMATION);

 }

 @Override
 protected Control createDialogArea(Composite parent) {
  GridLayout layout = new GridLayout();
  layout.numColumns = 2;
  // layout.horizontalAlignment = GridData.FILL;
  parent.setLayout(layout);

  // The text fields will grow with the size of the dialog
  GridData gridData = new GridData();
  gridData.grabExcessHorizontalSpace = true;
  gridData.horizontalAlignment = GridData.FILL;

  Label label1 = new Label(parent, SWT.NONE);
  label1.setText("First Name");

  firstNameText = new Text(parent, SWT.BORDER);
  firstNameText.setLayoutData(gridData);
  Label label2 = new Label(parent, SWT.NONE);
  label2.setText("Last Name");
  lastNameText = new Text(parent, SWT.BORDER);
  lastNameText.setLayoutData(gridData);
  return parent;
 }

 @Override
 protected void createButtonsForButtonBar(Composite parent) {
  GridData gridData = new GridData();
  gridData.verticalAlignment = GridData.FILL;
  gridData.horizontalSpan = 3;
  gridData.grabExcessHorizontalSpace = true;
  gridData.grabExcessVerticalSpace = true;
  gridData.horizontalAlignment = SWT.CENTER;

  parent.setLayoutData(gridData);
  // Create Add button
  // Own method as we need to overview the SelectionAdapter
  createOkButton(parent, OK, "Add", true);
  // Add a SelectionListener

  // Create Cancel button
  Button cancelButton = createButton(parent, CANCEL, "Cancel", false);
  // Add a SelectionListener
  cancelButton.addSelectionListener(new SelectionAdapter() {
   public void widgetSelected(SelectionEvent e) {
    setReturnCode(CANCEL);
    close();
   }
  });
 }

 protected Button createOkButton(Composite parent, int id, String label,
   boolean defaultButton) {
  // increment the number of columns in the button bar
  ((GridLayout) parent.getLayout()).numColumns++;
  Button button = new Button(parent, SWT.PUSH);
  button.setText(label);
  button.setFont(JFaceResources.getDialogFont());
  button.setData(new Integer(id));
  button.addSelectionListener(new SelectionAdapter() {
   public void widgetSelected(SelectionEvent event) {
    if (isValidInput()) {
     okPressed();
    }
   }
  });
  if (defaultButton) {
   Shell shell = parent.getShell();
   if (shell != null) {
    shell.setDefaultButton(button);
   }
  }
  setButtonLayoutData(button);
  return button;
 }

 private boolean isValidInput() {
  boolean valid = true;
  if (firstNameText.getText().length() == 0) {
   setErrorMessage("Please maintain the first name");
   valid = false;
  }
  if (lastNameText.getText().length() == 0) {
   setErrorMessage("Please maintain the last name");
   valid = false;
  }
  return valid;
 }

 // We allow the user to resize this dialog
 @Override
 protected boolean isResizable() {
  return true;
 }

 // We need to have the textFields into Strings because the UI gets disposed
 // and the Text Fields are not accessible any more.
 private void saveInput() {
  firstName = firstNameText.getText();
  lastName = lastNameText.getText();

 }

 @Override
 protected void okPressed() {
  saveInput();
  super.okPressed();
 }

 public String getFirstName() {
  return firstName;
 }

 public String getLastName() {
  return lastName;
 }
}

   

Add one command "de.vogella.rcp.intro.dialogs.custom.openMyDialog" and create the following handler "de.vogella.rcp.intro.dialogs.custom.handler.OpenMyDialog". Add the command to the menu.

    
package de.vogella.rcp.intro.dialogs.custom.handler;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.jface.window.Window;
import org.eclipse.ui.handlers.HandlerUtil;

import de.vogella.rcp.intro.dialogs.custom.dialogs.MyDialog;

public class OpenMyDialog extends AbstractHandler {

 @Override
 public Object execute(ExecutionEvent event) throws ExecutionException {
  MyDialog dialog = new MyDialog(HandlerUtil.getActiveWorkbenchWindow(
    event).getShell());
  dialog.create();
  if (dialog.open() == Window.OK) {
   System.out.println(dialog.getFirstName());
   System.out.println(dialog.getLastName());
  }

  return null;
 }

}

   

Run the application. You should be able to open the dialog. To press Ok you need to maintain the first and last name. If you press "Ok" both fields should be written to the console.