Java tutorial
/******************************************************************************* * Copyright (c) 2000, 2015 IBM Corporation and others. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html * * Contributors: * IBM Corporation - initial API and implementation *******************************************************************************/ package org.eclipse.jface.dialogs; import org.eclipse.jface.resource.StringConverter; import org.eclipse.swt.SWT; import org.eclipse.swt.layout.GridData; 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; /** * A simple input dialog for soliciting an input string from the user. * <p> * This concrete dialog class can be instantiated as is, or further subclassed as * required. * </p> */ public class InputDialog extends Dialog { /** * The title of the dialog. */ private String title; /** * The message to display, or <code>null</code> if none. */ private String message; /** * The input value; the empty string by default. */ private String value = "";//$NON-NLS-1$ /** * The input validator, or <code>null</code> if none. */ private IInputValidator validator; /** * Ok button widget. */ private Button okButton; /** * Input text widget. */ private Text text; /** * Error message label widget. */ private Text errorMessageText; /** * Error message string. */ private String errorMessage; /** * Creates an input dialog with OK and Cancel buttons. Note that the dialog * will have no visual representation (no widgets) until it is told to open. * <p> * Note that the <code>open</code> method blocks for input dialogs. * </p> * * @param parentShell * the parent shell, or <code>null</code> to create a top-level * shell * @param dialogTitle * the dialog title, or <code>null</code> if none * @param dialogMessage * the dialog message, or <code>null</code> if none * @param initialValue * the initial input value, or <code>null</code> if none * (equivalent to the empty string) * @param validator * an input validator, or <code>null</code> if none */ public InputDialog(Shell parentShell, String dialogTitle, String dialogMessage, String initialValue, IInputValidator validator) { super(parentShell); this.title = dialogTitle; message = dialogMessage; if (initialValue == null) { value = "";//$NON-NLS-1$ } else { value = initialValue; } this.validator = validator; } @Override protected void buttonPressed(int buttonId) { if (buttonId == IDialogConstants.OK_ID) { value = text.getText(); } else { value = null; } super.buttonPressed(buttonId); } @Override protected void configureShell(Shell shell) { super.configureShell(shell); if (title != null) { shell.setText(title); } } @Override protected void createButtonsForButtonBar(Composite parent) { // create OK and Cancel buttons by default okButton = createButton(parent, IDialogConstants.OK_ID, IDialogConstants.OK_LABEL, true); createButton(parent, IDialogConstants.CANCEL_ID, IDialogConstants.CANCEL_LABEL, false); //do this here because setting the text will set enablement on the ok // button text.setFocus(); if (value != null) { text.setText(value); text.selectAll(); } } @Override protected Control createDialogArea(Composite parent) { // create composite Composite composite = (Composite) super.createDialogArea(parent); // create message if (message != null) { Label label = new Label(composite, SWT.WRAP); label.setText(message); GridData data = new GridData(GridData.GRAB_HORIZONTAL | GridData.GRAB_VERTICAL | GridData.HORIZONTAL_ALIGN_FILL | GridData.VERTICAL_ALIGN_CENTER); data.widthHint = convertHorizontalDLUsToPixels(IDialogConstants.MINIMUM_MESSAGE_AREA_WIDTH); label.setLayoutData(data); label.setFont(parent.getFont()); } text = new Text(composite, getInputTextStyle()); text.setLayoutData(new GridData(GridData.GRAB_HORIZONTAL | GridData.HORIZONTAL_ALIGN_FILL)); text.addModifyListener(e -> validateInput()); errorMessageText = new Text(composite, SWT.READ_ONLY | SWT.WRAP); errorMessageText.setLayoutData(new GridData(GridData.GRAB_HORIZONTAL | GridData.HORIZONTAL_ALIGN_FILL)); errorMessageText.setBackground(errorMessageText.getDisplay().getSystemColor(SWT.COLOR_WIDGET_BACKGROUND)); // Set the error message text // See https://bugs.eclipse.org/bugs/show_bug.cgi?id=66292 setErrorMessage(errorMessage); applyDialogFont(composite); return composite; } /** * Returns the error message label. * * @return the error message label * @deprecated use setErrorMessage(String) instead */ @Deprecated protected Label getErrorMessageLabel() { return null; } /** * Returns the ok button. * * @return the ok button */ protected Button getOkButton() { return okButton; } /** * Returns the text area. * * @return the text area */ protected Text getText() { return text; } /** * Returns the validator. * * @return the validator */ protected IInputValidator getValidator() { return validator; } /** * Returns the string typed into this input dialog. * * @return the input string */ public String getValue() { return value; } /** * Validates the input. * <p> * The default implementation of this framework method delegates the request * to the supplied input validator object; if it finds the input invalid, * the error message is displayed in the dialog's message line. This hook * method is called whenever the text changes in the input field. * </p> */ protected void validateInput() { String errorMessage = null; if (validator != null) { errorMessage = validator.isValid(text.getText()); } // Bug 16256: important not to treat "" (blank error) the same as null // (no error) setErrorMessage(errorMessage); } /** * Sets or clears the error message. * If not <code>null</code>, the OK button is disabled. * * @param errorMessage * the error message, or <code>null</code> to clear * @since 3.0 */ public void setErrorMessage(String errorMessage) { this.errorMessage = errorMessage; if (errorMessageText != null && !errorMessageText.isDisposed()) { errorMessageText.setText(errorMessage == null ? " \n " : errorMessage); //$NON-NLS-1$ // Disable the error message text control if there is no error, or // no error text (empty or whitespace only). Hide it also to avoid // color change. // See https://bugs.eclipse.org/bugs/show_bug.cgi?id=130281 boolean hasError = errorMessage != null && (StringConverter.removeWhiteSpaces(errorMessage)).length() > 0; errorMessageText.setEnabled(hasError); errorMessageText.setVisible(hasError); errorMessageText.getParent().update(); // Access the ok button by id, in case clients have overridden button creation. // See https://bugs.eclipse.org/bugs/show_bug.cgi?id=113643 Control button = getButton(IDialogConstants.OK_ID); if (button != null) { button.setEnabled(errorMessage == null); } } } /** * Returns the style bits that should be used for the input text field. * Defaults to a single line entry. Subclasses may override. * * @return the integer style bits that should be used when creating the * input text * * @since 3.4 */ protected int getInputTextStyle() { return SWT.SINGLE | SWT.BORDER; } }