/*-
* Copyright 2010 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.authenticator.blackberry;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.component.NullField;
/**
* Utility methods for using BlackBerry {@link Field Fields}.
*/
public class FieldUtils {
public static boolean isVisible(Field field) {
return field.getManager() != null;
}
/**
* BlackBerry {@link Field Fields} do not support invisibility, so swap in an
* invisible placeholder to simulate invisibility.
* <p>
* The placeholder field is stored with {@link Field#setCookie(Object)}.
* <p>
* The non-placeholder field must be added to a {@link Manager} before marking
* is as <em>invisible</em> so that the implementation knows where to insert
* the placeholder.
*
* @param field
* the field to toggle.
* @param visible
* the new visibility.
*/
public static void setVisible(Field field, boolean visible) {
NullField peer = (NullField) field.getCookie();
if (visible && !isVisible(field)) {
if (peer == null) {
throw new IllegalStateException("Placeholder missing");
}
Manager manager = peer.getManager();
manager.replace(peer, field);
} else if (!visible && isVisible(field)) {
if (peer == null) {
peer = new NullField();
field.setCookie(peer);
}
Manager manager = field.getManager();
manager.replace(field, peer);
}
}
FieldUtils() {
}
}