com.google.gwt.user.client.ui.ValueLabel Maven / Gradle / Ivy
/*
* 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.gwt.user.client.ui;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;
import com.google.gwt.editor.client.IsEditor;
import com.google.gwt.editor.client.LeafValueEditor;
import com.google.gwt.editor.client.adapters.TakesValueEditor;
import com.google.gwt.text.shared.Parser;
import com.google.gwt.text.shared.Renderer;
import com.google.gwt.text.shared.ToStringRenderer;
import com.google.gwt.uibinder.client.UiConstructor;
import com.google.gwt.user.client.TakesValue;
import java.text.ParseException;
/**
* A label displaying its value through a renderer.
*
* @param the value type.
*/
public class ValueLabel extends LabelBase implements TakesValue,
IsEditor> {
/**
* Creates a ValueLabel widget that wraps an existing <span> element.
*
* The ValueLabel's value will be null, whether the element being
* wrapped has content or not. Use {@link #wrap(Element, Renderer, Parser)} to
* parse the initial element's content to initialize the ValueLabel's value.
*
* This element must already be attached to the document. If the element is
* removed from the document, you must call
* {@link RootPanel#detachNow(Widget)}.
*
* @param element the element to be wrapped
* @param renderer the renderer used to render values into the element
*/
public static ValueLabel wrap(Element element,
Renderer renderer) {
// Assert that the element is attached.
assert Document.get().getBody().isOrHasChild(element);
ValueLabel label = new ValueLabel(element, renderer);
// Mark it attached and remember it for cleanup.
label.onAttach();
RootPanel.detachOnWindowClose(label);
return label;
}
/**
* Creates a ValueLabel widget that wraps an existing <span> element.
*
* The ValueLabel's value will be initialized with the element's content,
* passed through the parser.
*
* This element must already be attached to the document. If the element is
* removed from the document, you must call
* {@link RootPanel#detachNow(Widget)}.
*
* @param element the element to be wrapped
* @param renderer the renderer used to render values into the element
* @param parser the parser used to initialize the ValueLabel's value from the
* element's content
*/
public static ValueLabel wrap(Element element,
Renderer renderer, Parser parser)
throws ParseException {
ValueLabel label = wrap(element, renderer);
label.setValue(parser.parse(element.getInnerText()));
// Mark it attached and remember it for cleanup.
label.onAttach();
RootPanel.detachOnWindowClose(label);
return label;
}
private final Renderer renderer;
private T value;
private LeafValueEditor editor;
public ValueLabel() {
this(ToStringRenderer.instance());
}
/**
* Creates an empty value label.
*
* @param renderer
*/
@UiConstructor
public ValueLabel(Renderer renderer) {
super(true);
this.renderer = renderer;
}
/**
* This constructor may be used by subclasses to explicitly use an existing
* element. This element must be either a <span> or a <div>
* element.
*
* @param element the element to be used
*/
protected ValueLabel(Element element, Renderer renderer) {
super(element);
this.renderer = renderer;
}
public LeafValueEditor asEditor() {
if (editor == null) {
editor = TakesValueEditor.of(this);
}
return editor;
}
public T getValue() {
return value;
}
public void setValue(T value) {
this.value = value;
directionalTextHelper.setText(renderer.render(value));
updateHorizontalAlignment();
}
}