Bug 248410 - [Wizards] Accessibility: User is not alerted to error

message displayed in wizard dialog

1 files changed, 110 insertions, 0 deletions

diff --git a/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet363.java b/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet363.java
new file mode 100644
index 0000000000..88e5dd12b9
--- /dev/null
+++ b/examples/org.eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet363.java
@@ -0,0 +1,110 @@
+/*******************************************************************************
+ * Copyright (c) 2012 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.swt.snippets;
+
+/*
+ * Accessibility example snippet: Declare a message area to be a "live region",
+ * and send "changed" events to a screen reader when the message area is updated.
+ *
+ * For a list of all SWT example snippets see
+ * http://www.eclipse.org/swt/snippets/
+ */
+import org.eclipse.swt.*;
+import org.eclipse.swt.accessibility.*;
+import org.eclipse.swt.events.*;
+import org.eclipse.swt.graphics.*;
+import org.eclipse.swt.layout.*;
+import org.eclipse.swt.widgets.*;
+
+public class Snippet363 {
+    static final String errorMessage = "Error: Number expected.";
+    static Label icon;
+    static Image errorIcon;
+    static Text liveLabel;
+
+public static void main(String [] args) {
+    Display display = new Display();
+    errorIcon = display.getSystemImage(SWT.ICON_ERROR);
+    Shell shell = new Shell(display);
+    shell.setLayout(new GridLayout(2, false));
+    shell.setText("LiveRegion Test");
+    
+    icon = new Label(shell, SWT.NONE);
+    icon.setLayoutData(new GridData(32, 32));
+    
+    liveLabel = new Text(shell, SWT.READ_ONLY);
+    GC gc = new GC(liveLabel);
+    Point pt = gc.textExtent(errorMessage);
+    GridData data = new GridData(SWT.FILL, SWT.CENTER, true, false);
+    data.minimumWidth = pt.x + gc.getFontMetrics().getAverageCharWidth() * 2;
+    gc.dispose();
+    liveLabel.setLayoutData(data);
+    liveLabel.setText("");
+    liveLabel.getAccessible().addAccessibleAttributeListener(new AccessibleAttributeAdapter() {
+            public void getAttributes(AccessibleAttributeEvent e) {
+                    e.attributes = new String[] {
+                                    "container-live", "polite",
+                                    "live", "polite",
+                                    "container-live-role", "status",
+                            };
+            }
+    });
+    
+    final Label textFieldLabel = new Label(shell, SWT.NONE);
+    textFieldLabel.setText("Type a number:");
+    textFieldLabel.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 2, 1));
+    
+    final Text textField = new Text(shell, SWT.SINGLE | SWT.BORDER);
+    textField.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 2, 1));
+
+    final Button okButton = new Button(shell, SWT.PUSH);
+    okButton.setText("OK");
+    okButton.setLayoutData(new GridData(SWT.END, SWT.CENTER, false, false, 2, 1));
+    okButton.setEnabled(false);
+
+    textField.addModifyListener(new ModifyListener() {
+            public void modifyText(ModifyEvent e) {
+                    boolean isNumber = false;
+                    String textValue = textField.getText();
+                    try {
+                            Integer.parseInt(textValue);
+                            isNumber = true;
+                            setMessageText(false, "Thank-you");
+                    } catch (NumberFormatException ex) {
+                            if (textValue.isEmpty()) {
+                                    setMessageText(false, "");
+                            } else {
+                                    setMessageText(true, "Error: Number expected.");
+                            }
+                    }
+                    okButton.setEnabled(isNumber);
+            }
+    });
+    
+    textField.setFocus();
+    shell.pack();
+    shell.open();
+    while (!shell.isDisposed()) {
+            if (!display.readAndDispatch()) display.sleep();
+    }
+    display.dispose();
+}
+
+static void setMessageText(boolean error, String newMessage) {
+    String oldMessage = liveLabel.getText();
+    icon.setImage(error ? errorIcon : null);
+    liveLabel.setText(newMessage);
+    liveLabel.getAccessible().sendEvent(ACC.EVENT_ATTRIBUTE_CHANGED, null);
+    liveLabel.getAccessible().sendEvent(ACC.EVENT_TEXT_CHANGED, new Object[] {ACC.TEXT_DELETE, 0, oldMessage.length(), oldMessage});
+    liveLabel.getAccessible().sendEvent(ACC.EVENT_TEXT_CHANGED, new Object[] {ACC.TEXT_INSERT, 0, newMessage.length(), newMessage});
+}
+
+}