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/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview A simple, sample component.
*/
goog.provide('goog.demos.SampleComponent');
goog.require('goog.dom');
goog.require('goog.dom.TagName');
goog.require('goog.dom.classlist');
goog.require('goog.events.EventType');
goog.require('goog.events.KeyCodes');
goog.require('goog.events.KeyHandler');
goog.require('goog.ui.Component');
goog.requireType('goog.events.Event');
/**
* A simple box that changes colour when clicked. This class demonstrates the
* goog.ui.Component API, and is keyboard accessible, as per
* http://wiki/Main/ClosureKeyboardAccessible
* @final
* @unrestricted
*/
goog.demos.SampleComponent = class extends goog.ui.Component {
/**
* @param {string=} opt_label A label to display. Defaults to "Click Me" if
* none provided.
* @param {goog.dom.DomHelper=} opt_domHelper DOM helper to use.
*/
constructor(opt_label, opt_domHelper) {
super(opt_domHelper);
/**
* The label to display.
* @type {string}
* @private
*/
this.initialLabel_ = opt_label || 'Click Me';
/**
* The current color.
* @type {string}
* @private
*/
this.color_ = 'red';
/**
* Keyboard handler for this object. This object is created once the
* component's DOM element is known.
*
* @type {goog.events.KeyHandler?}
* @private
*/
this.kh_ = null;
}
/**
* Changes the color of the element.
* @private
*/
changeColor_() {
if (this.color_ == 'red') {
this.color_ = 'green';
} else if (this.color_ == 'green') {
this.color_ = 'blue';
} else {
this.color_ = 'red';
}
this.getElement().style.backgroundColor = this.color_;
}
/**
* Creates an initial DOM representation for the component.
* @override
*/
createDom() {
this.decorateInternal(this.dom_.createElement(goog.dom.TagName.DIV));
}
/**
* Decorates an existing HTML DIV element as a SampleComponent.
*
* @param {Element} element The DIV element to decorate. The element's
* text, if any will be used as the component's label.
* @override
* @suppress {strictMissingProperties} missing tabIndex prop
*/
decorateInternal(element) {
super.decorateInternal(element);
if (!this.getLabelText()) {
this.setLabelText(this.initialLabel_);
}
const elem = this.getElement();
goog.dom.classlist.add(elem, goog.getCssName('goog-sample-component'));
elem.style.backgroundColor = this.color_;
elem.tabIndex = 0;
this.kh_ = new goog.events.KeyHandler(elem);
this.getHandler().listen(
this.kh_, goog.events.KeyHandler.EventType.KEY, this.onKey_);
}
/** @override */
disposeInternal() {
super.disposeInternal();
if (this.kh_) {
this.kh_.dispose();
}
}
/**
* Called when component's element is known to be in the document.
* @override
*/
enterDocument() {
super.enterDocument();
this.getHandler().listen(
this.getElement(), goog.events.EventType.CLICK, this.onDivClicked_);
}
/**
* Gets the current label text.
*
* @return {string} The current text set into the label, or empty string if
* none set.
*/
getLabelText() {
if (!this.getElement()) {
return '';
}
return goog.dom.getTextContent(this.getElement());
}
/**
* Handles DIV element clicks, causing the DIV's colour to change.
* @param {goog.events.Event} event The click event.
* @private
*/
onDivClicked_(event) {
this.changeColor_();
}
/**
* Fired when user presses a key while the DIV has focus. If the user presses
* space or enter, the color will be changed.
* @param {goog.events.Event} event The key event.
* @private
* @suppress {strictMissingProperties} missing 'keyCode' prop
*/
onKey_(event) {
const keyCodes = goog.events.KeyCodes;
if (event.keyCode == keyCodes.SPACE || event.keyCode == keyCodes.ENTER) {
this.changeColor_();
}
}
/**
* Sets the current label text. Has no effect if component is not rendered.
*
* @param {string} text The text to set as the label.
*/
setLabelText(text) {
if (this.getElement()) {
goog.dom.setTextContent(this.getElement(), text);
}
}
};
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