jiti-meet/modules/UI/overlay/Overlay.js

83 lines
2.1 KiB
JavaScript

/* global $, APP */
/**
* Base class for overlay components - the components which are displayed on
* top of the application with semi-transparent background covering the whole
* screen.
*/
export default class Overlay{
/**
* Creates new <tt>Overlay</tt> instance.
*/
constructor() {
/**
*
* @type {jQuery}
*/
this.$overlay = null;
}
/**
* Template method which should be used by subclasses to provide the overlay
* content. The contents provided by this method are later subject to
* the translation using {@link APP.translation.translateElement}.
* @return {string} HTML representation of the overlay dialog contents.
* @private
*/
_buildOverlayContent() {
return '';
}
/**
* Constructs the HTML body of the overlay dialog.
*/
buildOverlayHtml() {
let overlayContent = this._buildOverlayContent();
this.$overlay = $(`
<div class='overlay_container'>
<div class='overlay_content'>
${overlayContent}
</div>
</div>`);
APP.translation.translateElement(this.$overlay);
}
/**
* Checks whether the page reload overlay has been displayed.
* @return {boolean} <tt>true</tt> if the page reload overlay is currently
* visible or <tt>false</tt> otherwise.
*/
isVisible() {
return this.$overlay && this.$overlay.parents('body').length > 0;
}
/**
* Template method called just after the overlay is displayed for the first
* time.
* @private
*/
_onShow() {
// To be overridden by subclasses.
}
/**
* Shows the overlay dialog adn attaches the underlying HTML representation
* to the DOM.
*/
show() {
!this.$overlay && this.buildOverlayHtml();
if (!this.isVisible()) {
this.$overlay.appendTo('body');
this._onShow();
}
}
/**
* Hides the overlay dialog and detaches it's HTML representation from
* the DOM.
*/
hide() {
this.$overlay && this.$overlay.detach();
}
}