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/*******************************************************************************
* Copyright (c) 2012, 2016 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.
* Note: This snippet will only work with Windows screen readers.
*
* 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.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 = (int) (pt.x + gc.getFontMetrics().getAverageCharacterWidth() * 2);
gc.dispose();
liveLabel.setLayoutData(data);
liveLabel.setText("");
liveLabel.getAccessible().addAccessibleAttributeListener(new AccessibleAttributeAdapter() {
@Override
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(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});
}
}
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