Adding Dialogs

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by Adam Boduch | July 2013 | Cookbooks Open Source

In this article, by Adam Boduch, author of Getting Started with Microsoft Lync Server 2013, we will cover the following recipes:

  • Applying effects to dialog components
  • Waiting for API data to load
  • Using icons in the dialog title
  • Adding actions to the dialog title
  • Applying effects to dialog resize interactions
  • Using modal dialogs for messages

The dialog widget gives UI developers a tool with which they can present the user with forms or other pieces of information without disrupting what is currently on the page; dialogs create a new context. Out-of-the-box, developers can do a lot with dialog options, and many of these capabilities are turned on by default. This includes the ability to resize the dialog, and move it around on the page.

In this article, we'll address some common pitfalls of dialog usage typical in any web application. There is often a need to adjust the controls of the dialog and its overall appearance; we'll touch on a few of those. We'll also look at how interacting with API data complicates dialog usage and the ways to deal with that. Finally, we can add some polish to dialog widgets by looking at the various ways in which we can apply effects to them.

(For more resources related to this topic, see here.)

Applying effects to dialog components

Out-of-the-box, the dialog widget allows developers to show animations when the dialog is opened, as well as hide animations, when closed. This animation is applied to the dialog as a whole. So, for example, if we were to specify that the show option is a fade animation, the entire dialog will fade into view for the user. Likewise, if the hide option was fade, the dialog would fade out of view instead of instantaneously disappearing. To liven up this show and hide behavior, we could operate on individual dialog components. That is, instead of applying show and hide effects to the dialog as a whole, we could apply them to the individual parts inside the widget, like the title bar and the button pane.

How to do it...

The dialog we're going to create here is just about as simple as they come in terms of content. That is, we're going to only specify some basic title and content strings for the dialog in the HTML.

<div title="Dialog Title"> <p>Basic dialog content</p> </div>

In order to turn this idea of animating individual dialog components into reality, we'll have to extend the dialog widget in a few places. In particular, we're going to animate the title bar, at the top of the widget, as well as the button pane near the bottom. Here is what the JavaScript code looks like:

(function( $, undefined ) { $.widget( "ab.dialog", $.ui.dialog, { _create: function() { this._super(); var dialog = this.uiDialog; dialog.find( ".ui-dialog-titlebar" ).hide(); dialog.find( ".ui-dialog-buttonpane" ).hide(); }, open: function() { this._super(); var dialog = this.uiDialog; dialog.find( ".ui-dialog-titlebar" ).toggle( "fold", 500 ); dialog.find( ".ui-dialog-buttonpane" ).toggle( "fold", 500 ); }, close: function( event, isCallback ) { var self = this, dialog = this.uiDialog; if ( isCallback ) { this._super( event ); return; } dialog.find( ".ui-dialog-titlebar" ).toggle( "fold", 500 ); dialog.find( ".ui-dialog-buttonpane" ).toggle( "fold", 500, function(){ self.element.dialog( "close", event, true ); }); } }); })( jQuery ); $(function() { $( "div" ).dialog({ show: "fade", hide: "scale", buttons: { Cancel: function() { $( this ).dialog( "close" ); } } }); });

When you open the page, you'll see the individual dialog components fade into view, independent of the fade animation we've specified for the dialog as a whole. Once visible, the dialog should look something like this:

You'll also notice that the scale effect isn't applied until the fade effect is applied to the title bar and button panes.

How it works...

This code is one of those exceptions to the rule where we're not providing a mechanism with which to turn off our new extended functionality. That is, we have hard-coded changes in our custom implementation of some dialog methods that cannot be turned off by supplying an option value. However, the exception is made in an effort to trade-off complexity for desired functionality. Chances are that this type of custom animation work would happen as part of a specific project requirement, and not as a generalized extension of the dialog widget capabilities.

The first thing we change about the default dialog implementation is in the _create() method, where we hide the .ui-dialog-titlebar and .ui-dialog-buttonpane components. This is done after calling the _super() method, which is responsible for creating the basic dialog components. Even if the dialog is set to open automatically with the autoOpen option, the _create() method doesn't actually display it. So, we can hide the title bar and button pane without the user noticing it.

The reason we've hidden the two components is because we would like to apply a display effect once the dialog opens. The next method, open(), that we're overriding does exactly that. It first calls the _super() method, which initiates the effect for displaying the dialog (in our case, we've told it to fade on display). We then use the fold effect on the title bar and on the button pane.

You'll notice that we don't wait for any animations to complete before starting the next. The dialog display animation is started, followed by the title bar and the button pane. All three could be executing at the same time, potentially. The reason we've done it this way is to retain the correct layout of the dialog. The last method to override is the close() method. This introduces an interesting work-around we must use in order to get _super() to work in a callback. Even with the self variable in the enclosing scope, we have problems calling the _super() method inside the callback. So, we use the widget element and pretend like we're calling .dialog( "close" ) from outside of the widget. The isCallback argument tells the close() method to call _super(), and return. The reason we need a callback to begin with is that we don't actually want to execute the dialog hide animation until we've finished animating the button pane.

Waiting for API data to load

More often than not, the dialog widget needs to load data from an API. That is, not all dialogs are composed of static HTML. They need data from the API to construct some of the elements using API data, such as select element options.

Loading data from the API and building the resultant elements isn't the issue; we do this all the time. The challenge comes when we try to perform these activities within the dialog context. We don't necessarily want to display the dialog until the data has been loaded from the API, and the UI components used to display them inside the dialog components have been built. Ideally, we would block the dialog from displaying until the components displayed by the dialog are ready.

This is especially tricky with remote API functionally, where it is impossible to predict latency issues. Furthermore, the dialog may depend on more than one API call, each populating its own UI component in the dialog.

Getting ready...

To implement a solution for the API data problem, we'll need some basic HTML and CSS to define the dialog and its content. We'll have two empty select elements in the dialog. This is what the HTML looks like:

<div id="dialog" title="Genres and Titles"> <div class="dialog-field"> <label for="genres">Genres:</label> <select id="genres"></select> <div class="ui-helper-clearfix"></div> </div> <div class="dialog-field"> <label for="titles">Titles:</label> <select id="titles"></select> <div class="ui-helper-clearfix"></div> </div> </div>

And, this is the supporting CSS for the previous code:

.dialog-field { margin: 5px; } .dialog-field label { font-weight: bold; font-size: 1.1em; float: left; } .dialog-field select { float: right; }

How to do it...

We'll give the dialog widget the ability to block while waiting on API requests by extending the widget with a new option. This option will allow us to pass in an array of deferred promises. A promise is an object used to track the state of an individual Ajax call. With a collection of promises, we're able to implement complex blocking behavior using simple code like this:

(function( $, undefined ) { $.widget( "ab.dialog", $.ui.dialog, { options: { promises: [] }, open: function( isPromise ) { var $element = this.element, promises = this.options.promises; if ( promises.length > 0 && !isPromise ) { $.when.apply( $, promises ).then( function() { $element.dialog( "open", true ); }); } else { this._super(); } }, }); })( jQuery ); $(function() { var repos = $.ajax({ url: "https://api.github.com/repositories", dataType: "jsonp", success: function( resp ) { $.each( resp.data, function( i, v ) { $( "<option/>" ).html( v.name ) .appendTo( "#repos" ); }); }, }); var users = $.ajax({ url: "https://api.github.com/users", dataType: "jsonp", success: function( resp ) { $.each( resp.data, function( i, v ) { $( "<option/>" ).html( v.login ) .appendTo( "#users" ); }); } }); $( "#dialog" ).dialog({ width: 400, promises: [ repos.promise(), users.promise() ] }); });

Once the API data is returned, for both the calls, the dialog is displayed and should look something like this:

How it works...

Let's start by looking at the document ready handler where we're actually instantiating the dialog widget. The first two variables defined here, repos and users, are $.Deferred objects. These represent two API calls we're making to the GitHub API. The objective of these calls is to populate the #repos and the #users select elements, respectively. These select elements make up part of our #dialog content. The success option specified in each Ajax call is a callback that performs the work of creating the option elements, and placing them in the select element.

Without customizing the dialog widget, these two API calls would work just fine. The dialog would open, and eventually, the options would appear in the select elements (after the dialog has already opened). You'll notice, however, that we're passing an array of deferred.promise() objects to the dialog. This is a new capability we've given to the dialog widget. A deferred object, simply put, allows developers to postpone the consequences of some action that might take a while to complete, such as an Ajax call. A promise is something we get from a deferred object that lets us compose some criteria that says when a complex sequence, such as making multiple Ajax calls, is complete.

The custom promises option we've added to the dialog widget is used in our implementation of the open() method. It is here that we can make use of these promises. Essentially, we're making a transaction out of one or more promise objects passed to the dialog—once they've all completed or resolved to use the jQuery terminology, we can open the dialog. We do so by passing the array of promise objects to the $.when() function, which calls the open() method on the dialog. However, a complication arises here that we must deal with. We can't call _super() from within a callback function because the core widget machinery doesn't understand how to find the parent widget class.

So, we have to pretend as though we're calling open() from outside of the widget. We do this by using self.element, and the additional isPromise parameter, instructing our custom open() implementation on how to behave.

Using icons in the dialog title

With some dialogs, depending on the nature of the application and the content of the dialog itself, it may be beneficial to place an icon beside the dialog title. This could be beneficial in the sense that it provides additional context to the user. For example, an edit dialog might have a pencil icon, whereas a user profile dialog might contain a person icon.

Getting ready...

To illustrate adding an icon to the title bar of the dialog widget, we'll use the following as our basic HTML:

<div id="dialog" title="Edit"> <div> <label>Field 1:</label> <input type="text"/> </div> <div> <label>Field 2:</label> <input type="text"/> </div> </div>

How to do it...

The first thing we'll need to define is a custom CSS class used to properly align the icon once we place it in the title bar of the dialog. The CSS looks like this:

.ui-dialog-icon { float: left; margin-right: 5px; }

Next, we have our JavaScript code to customize the dialog widget by adding a new icon option as well as creating an instance of the widget using our HTML as the source:

(function( $, undefined ) { $.widget( "ab.dialog", $.ui.dialog, { options: { icon: false }, _create: function() { this._super(); if ( this.options.icon ) { var iconClass = "ui-dialog-icon ui-icon " + this.options.icon; this.uiDialog.find( ".ui-dialog-titlebar" ) .prepend( $( "<span/>" ).addClass( iconClass )); } }, }); })( jQuery ); $(function() { $( "#dialog" ).dialog({ icon: "ui-icon-pencil", buttons: { Save: function() { $( this ).dialog( "close" ) } } }); });

The resulting dialog, when opened, should look something like the following:

How it works...

For this particular dialog instance, we would like to display the pencil icon. Our icon option we've added to the dialog widget allows the developer to specify an icon class from the theme framework. In this case, it's ui-icon-pencil. The new icon option has a default value of false.

We're overriding the default dialog implementation of the _create() method so that we can inject a new span element into the dialog title bar if the icon option was provided. This new span element gets the icon class passed as the new option value, in addition to the ui-dialog-icon class, which is used to position the icon we defined earlier.

Adding actions to the dialog title

By default, the dialog widget provides the user with one action that doesn't require developer intervention—the close button in the title bar. This is a universal action that applies to almost any dialog, as users would expect to be able to close them. Additionally, it isn't by accident that the close dialog action button is an icon positioned in the top-right corner of the dialog. This is a standard location and action in graphical windowing environments as well, in addition to other actions. Let's take a look at how we might go about extending the actions placed in the title bar of the dialog widget.

How to do it...

For this demonstration, we only need the following basic dialog HTML:

<div id="dialog" title="Dialog Title"> <p>Basic dialog content</p> </div>

Next, we'll implement our dialog specialization that adds a new option and some code that creates a new dialog instance using that option:

(function( $, undefined ) { $.widget( "ab.dialog", $.ui.dialog, { options: { iconButtons: false }, _create: function() { this._super(); var $titlebar = this.uiDialog.find( ".ui-dialog-titlebar" ); $.each( this.options.iconButtons, function( i, v ) { var button = $( "<button/>" ).text( v.text ), right = $titlebar.find( "[role='button']:last" ) .css( "right" ); button.button( { icons: { primary: v.icon }, text: false } ) .addClass( "ui-dialog-titlebar-close" ) .css( "right", (parseInt(right) + 22) + "px" ) .click( v.click ) .appendTo( $titlebar ); }); } }); })( jQuery ); $(function() { $( "#dialog" ).dialog({ iconButtons: [ { text: "Search", icon: "ui-icon-search", click: function( e ) { $( "#dialog" ).html( "<p>Searching...</p>" ); } }, { text: "Add", icon: "ui-icon-plusthick", click: function( e ) { $( "#dialog" ).html( "<p>Adding...</p>" ); } } ] }); });

When this dialog is opened, we'll see the new action buttons we passed to the dialog in the top-right corner, as shown in the following screenshot:

How it works...

We've created a new option for the dialog called iconButtons. This new option expects an array of objects, where each object has attributes related to an action button. Things like the text, the icon class, and the click event have to be executed when the user opens the dialog, and clicks on the button.

The bulk of the work in this customization takes place in our version of the _create() method. Here, we iterate over each button supplied in the iconButtons option. The first thing we do when inserting a new button into the title bar is create the button element. We also get the width of the last action button added using the .ui-dialog-titlebar [role='button']:last selector (this is needed to compute the horizontal placement of the action button).

Next, we bind the click event as specified in the button configuration. For each button in the array that we're adding, we want it placed to the left of the previous button. So when we first start iterating over the iconButtons array, the default close action is the last button in the title bar. Since the CSS structure requires a fixed right value, we have to compute it. And to do that, we need the value of the last button in the list.

Applying effects to dialog resize interactions

By default, the dialog widget allows users to resize by dragging the resize handle. The actual resize capability is provided by the resizable() interaction widget setup internally by the dialog when the resizable option is true. Let's take a look at how to gain access to the internal resizable component, so that we can use the animate feature. This option, when set on a resizable component, delays the redrawing of the resized component until the user has stopped dragging the resize handle.

Getting ready...

We only need simple dialog HTML for this demonstration, like this:

<div id="dialog" title="Dialog Title"> <p>Basic dialog content</p> </div>

How to do it...

Let's add a new option to the dialog widget called animateResize. When this option is true, we'll turn on the animate option of the internal resizable interaction widget.

(function( $, undefined ) { $.widget( "ab.dialog", $.ui.dialog, { options: { animateResize: false }, _makeResizable: function( handles ) { handles = (handles === undefined ? this.options.resizable : handles); var that = this, options = this.options, position = this.uiDialog.css( "position" ), resizeHandles = typeof handles === 'string' ? handles: "n,e,s,w,se,sw,ne,nw"; function filteredUi( ui ) { return { originalPosition: ui.originalPosition, originalSize: ui.originalSize, position: ui.position, size: ui.size }; } this.uiDialog.resizable({ animate: this.options.animateResize, cancel: ".ui-dialog-content", containment: "document", alsoResize: this.element, maxWidth: options.maxWidth, maxHeight: options.maxHeight, minWidth: options.minWidth, minHeight: this._minHeight(), handles: resizeHandles, start: function( event, ui ) { $( this ).addClass( "ui-dialog-resizing" ); that._trigger( "resizeStart", event, filteredUi( ui ) ); }, resize: function( event, ui ) { that._trigger( "resize", event, filteredUi( ui ) ); }, stop: function( event, ui ) { $( this ).removeClass( "ui-dialog-resizing" ); options.height = $( this ).height(); options.width = $( this ).width(); that._trigger( "resizeStop", event, filteredUi( ui ) ); if ( that.options.modal ) { that.overlay.resize(); } } }) .css( "position", position ) .find( ".ui-resizable-se" ) .addClass( "ui-icon ui-icon-grip-diagonal-se" ); } }); })( jQuery ); $(function() { $( "#dialog" ).dialog({ animateResize: true }); });

When this dialog is created and displayed, you'll be able to resize the dialog, observing that the actual resize is now animated.

How it works...

We've added the animateResize option to the dialog and provided it with a default value of false. To actually perform this capability, we've completely overwritten the _makeResizable() method, which the dialog widget uses internally when the dialog is created. In fact, we've taken the internal code for _makeResizable() and changed only one thing about it—animate: this.options.animateResize.

This is slightly redundant, copying all this code for turning on a simple feature like animating the dialog resize interaction. Indeed, it isn't the ideal solution. A better approach would be to call the _super() version of _makeResizable(), then just turn on animate by calling this.uiDialog.resizable( "option", "animate", true ). But at the time of this writing, this doesn't behave as expected. Our alternative route, even though it involves redundant code, just goes to show the flexibility of the widget factory. If this animation quality were a real requirement of a user interface, we quickly found a work-around with a negligible trade-off.

Using modal dialogs for messages

The dialog widget has a modal option reserved for when we need to focus the user's attention on just one thing. This option displays the dialog while preventing the user from interacting with the rest of the user interface. They have no choice but to take notice. This goes without saying, the modal dialog should be used sparingly, especially if you want to use it to broadcast messages to the user.

Let's look at how we can strip down the dialog in order to construct a generic notification tool in our application. It is a modal dialog in essence that is used for those cases where we cannot let the user continue what they're doing without ensuring they've seen our message.

Getting ready...

Here is what the HTML we'll need for this example looks like. Notice that the #notify div, which will become a dialog widget, has no content as our new notify widget will supply some.

<div id="notify"></div> <button id="show-info">Show Info</button> <button id="show-error">Show Error</button>

How to do it...

Let's go ahead and define a new notify widget, capable of displaying both error and information messages to the user like this:

(function( $, undefined ) { $.widget( "ab.notify", $.ui.dialog, { options: { modal: true, resizable: false, draggable: false, minHeight: 100, autoOpen: false, error: false }, open: function() { var error = this.options.error, newClass = error ? "ui-state-error" : "ui-state-highlight", oldClass = error ? "ui-state-highlight" : "ui-state-error"; this.element.html( this.options.text ); this.uiDialog.addClass( newClass ) .removeClass( oldClass ) .find( ".ui-dialog-titlebar" ) .removeClass( "ui-widget-header ui-corner-all" ); this._super(); }, }); })( jQuery ); $(function() { $( "#notify" ).notify(); $( "#show-info, #show-error" ).button(); $( "#show-info" ).click( function( e ) { $( "#notify" ).notify( "option", { error: false, text: "Successfully completed task" }); $( "#notify" ).notify( "open" ); }); $( "#show-error" ).click(function( e ) { $( "#notify" ).notify( "option", { error: true, text: "Failed to complete task" }); $( "#notify" ).notify( "open" ); })

The two buttons we've created here are used for demonstrating the notify widget's capabilities. If you click the #show-info button, you'll see the following informational message:

If you click the #show-error button, you'll see this error message:

How it works...

The notify widget we've just created inherits all of the dialog widget's capabilities. The first thing we define in our widget is the available options. In this case, we're extending the options object of the dialog widget, and adding some new options. You'll notice, too, that we're providing some updated default values for the dialog options such as turning modal on and turning draggable off. Every notify instance will share these defaults, so it doesn't make much sense to have to define them each and every time.

The open() method belongs to the dialog widget, and we're overriding it here to implement custom functionality that inserts the text of the notification message into the dialog content. We also set the state of the dialog based on the error option. If this is an error message, we apply the ui-state-error class to the entire dialog. If the error option is false, we apply the ui-state-highlight class. Finally, the dialog title bar component is stripped down by removing some classes, since we're not using it in the message display.

In the application code, the first thing we're creating is an instance of the notify widget. We then create the demo buttons and bind the click event to the functionality that will display an error message or an informational one, depending on which button is clicked.

Summary

This article covered loading data and dialog display issues. It also covered topics like adding effects to the widget and changing the dialog title bar.

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About the Author :


Adam Boduch

Adam Boduch has spent the last several years developing user interfaces for large-scale software systems. Starting out as a backend Python developer, he was lured to the frontend by tools like jQuery UI. Adam is passionate about readable code, and writes extensively about jQuery UI widgets, including his previous book jQuery UI Themes Beginner's Guide, Packt Publishing.

When Adam isn't coding, reading or writing, you will usually find him playing hockey, or spending time with his family.

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