JoJavaScript Framework for HTML5
Jo is a lightweight JavaScript framework designed for HTML5 apps.
$
and other arcane looking symbols in place of proper identifiersDave Balmer: davebalmer.wordpress.com, follow @balmer on Twitter, or email dbalmerjr@gmail.com
Version 0.4.1 is the latest stable release, check the Release Notes for details.
Available from GitHub as a git repo or a zip file.
If you want to jam an existing web page into an application framework, jo probably isn't for you. jo is designed to create applications. While it will play nicely with a mixture of new and old web development techniques, it uses HTML5 as a development stack and does not require direct DOM manipulation.
JavaScript Application | ||||||
jo | PhoneGap (optional) | |||||
---|---|---|---|---|---|---|
joView | joEvent | joDataSource | ||||
CSS3 | Canvas | DOM | Events | XHR | SQLite | Device OS |
All documentation for the framework is based on
Markdown
and provides a simple, natural and flexible way to document the code. This simple set
of perl
scripts has become its own tool called joDoc.
Jo is a JavaScript framework for HTML5 capable browsers and devices. It was originally designed to work on mobile platforms as a GUI and light data layer on top of PhoneGap. Since its creation, Jo has also been tested successfully as a lightweight framework for mobile browsers, newer desktop browsers, and even Dashboard widgets.
It's pretty easy to build on your own, but to get the most out of it you'll
want to get a minifier like jsmin
or the YUI Compressor. Minified and
gzipped, Jo weighs in around 9K with no other JavaScript library dependancies.
cd jo
./build
cd jo
build.bat
If you're not up for building the library yourself, there's nothing wrong with downloading the latest stable release, all built and ready to plug in from: jo/downloads">GitHub Downloads
Important files in the directory tree are:
js/jo_min.js
This is the jo library bundled and minified, ready to drop into your project. You
will need to build the library to make this file (as well as the un-minified
version jo.js
which is useful for debugging).
css/aluminum
This is a CSS3 bundle ready to ship your app with. Also serves as a good example of modern HTML5 styling capabilities. Looks pretty bad in IE up through version 8.
css/jo.css
This is a newer base CSS theme for Jo, preferred over Aluminum for now. Built with Less CSS compiler.
docs/*.mdown
These are supplimental doc files which are used by joDoc to build out the developer guide portions of the documentation.
The complete jo library is small, so in most cases you'll just want to pull it all in, like this:
<html>
<head>
<link rel="stylesheet" type="text/css" href="css/aluminum.css">
<link rel="stylesheet" type="text/css" href="css/webkit.css">
<!-- <link rel="stylesheet" type="text/css" href="css/webos.css"> -->
<!-- <link rel="stylesheet" type="text/css" href="css/chrome.css"> -->
</head>
<body>
<!-- any static page content goes here -->
<!-- load jo library -->
<script src="jo_min.js"></script>
<!-- any application JavaScript files go here -->
<script src="hello.js"></script>
</body>
</html>
If you're using jo to create all the UI for your application, you won't need any content
or tags in your index.html
file.
Since the framework is highly dependent on CSS, your mileage may vary across platforms. In particular, Internet Explorer before 9 will have limited eye candy and no animated transitions.
You can also completely skin your app with your own CSS, or augment the basic jo CSS to suit your purposes.
Since jo is geared for HTML5 applications, I recommend you develop and test your apps with Safari or Chrome before moving to mobile devices. In fact, this makes the code/test/debug cycle go very quickly.
jo has some initialization which should only be done when your browser is ready to have its DOM fiddled with, so you may want to wrap your code in a function that's called when your page loads, or your device signals that your app is ready to go.
The simplest UI would be something like:
// initialize jo
jo.load();
// define a wrapper for document.body
var scn = new joScreen();
// setup your UI
scn.alert("Hello, Jo!", "This is a simple alert.");
Something more interesting would look like:
// initialize jo
jo.load();
// setup a stack and screen
var stack = new joStackScroller();
var scn = new joScreen(stack);
// create our view card
var card = new joCard([
new joTitle("Hello"),
new joCaption("Hello World!"),
new joDivider(),
new joButton("OK").selectEvent.subscribe(function() {
stack.hide();
})
]);
// put the card on our view stack
stack.push(card);
Notice above that jo supports "chaining", meaning you can make successive calls inline to a given object (see the joButton line above for an example).
Of course, it is recommended you use more robust OOP coding patterns to make a proper application. While there's nothing illegal about putting everything in global space in a single JavaScript file, but if you're looking to build something big or more easy to maintain, I recommend you check out "JavaScript: the Good Parts" by Doug Crockford (O'Reilly Press).
The following is a class hierarchy for the framework, organized by general function.
Instead of a complex set of pseudo-class methods, jo uses a few simple coding patterns: singleton, base class, subclass, and module. All of these are found in modern JavaScript implementations. A good reference to have while developing your app is JavaScript: The Good Parts by Douglas Crockford (O'Reilly Press)
The pattern for creating a singleton is really just an object literal. For example:
MyApp = {
init: function() {
// some sort of initialization code goes here
},
mymethod: function() {
// some custom method
},
// properties can also be declared inline
myproperty: true
};
Prototypal inheritance does well with "fat" base classes which do most everything you anticipate a subclass would want. This type of inheritance benefits greatly from shallow/wide prototypes for a number of reasons. A base class looks something like:
MyClass = function(x) {
// constructor
this.x = x;
};
MyClass.prototype = {
mymethod: function() {
// some method
},
myothermethod: function() {
// another method
}
};
Strictly speaking, JavaScript doesn't have classes and subclasses. But it does know how to make copies of an object, and keeps track of "inheritance" through its prototype chain. A subclass in jo looks something like this:
MySubclass = function(x, y) {
//constructor
this.y = y;
// call to our "superclass" constructor
MyClass.call(this, x);
};
MySubclass.extend(MyClass, {
mynewmethod: function() {
// this subclass has its own new method
}
});
A couple things to note. jo augments the Function object in JavaScript to
have an extend()
method. This is just some syntactic sugar which makes it
easier to extend an object, giving us a pseudo-subclass with syntax that's
not too awkward. The advantage here is we're using JavaScript's natural
object model behind the scenes. We're not creating any extra fluff, just
automating the process somewhat.
Note that objects created using prototypal inheritance also get the benefit of
using JavaScript's built-in instanceof
operator which works up the
prototype chain. For example:
// given this new subclass
var someobject = new MySubclass(1, 2);
// both of these tests are "true"
joLog(someobject instanceof MySubclass);
joLog(someobject instanceof MyClass);
You may also notice a "call to super" comment in our MySubclass
constructor.
This is a convenient coding pattern which makes it easier to create subclasses,
with methods that augment the superclass' functionality. Like this:
MySubclass.extend(MyClass, {
mynewmethod: function() {
// this subclass has its own new method
},
mymethod: function() {
this.x += 5;
// call super's mymethod() with this object's context
MyClass.prototype.mymethod.apply(this, arguments);
}
});
It may look slightly odd at first, but this approach gives us more of the benefits of subclassing you'd find in other languages without having to step outside of JavaScript's natural object model.
Jo isn't just a pretty face with some DOM fiddling and standard DOM events. It also has a versatile application-level event model (see Observer Pattern). In addition, Jo has a simple event-driven layer for asynchronous data storage and retrieval using extensions of joDataSource.
As a matter of convenience, all children of joControl (which includes most list or widget-driven UI elements) can be easily tied to data.
The most convenient for most purposes is joRecord. This class wraps a property list, which can be used to save or load using whatever your application requires. In addition, this class allows you to link a UI control to the data in one quick action.
For more on this, check out the joRecord docs which include an example or two.
joDoc is a plain text code documentation scheme for JavaScript. It was created out of frustration felt working with various documentation systems available.
/**
myClass
=======
This is my class. It rocks, and this is its _description_, which also
rocks.
Extends
-------
- someOtherClass
Methods
-------
- setName(name)
Where `name` is a `String`.
Use
---
// here is some sample code which shows how to use this class
var x = new myClass(name);
> Note: use of the `name` reserved word is probaly a bad idea.
*/
You can put your comments for your code either:
in your source code (anywhere and in as many pieces as you want) denoted with
/** ... */
multiline-comment blocks
separate markdown (*.mdown
) files, probably (tho not necessarily) named to
match your JavaScript files
Can't get much more flexible than that.
JavaScript is an extremely expressive language which is often difficult to describe in terms of meta data and fields. Often, important information that needs to be documented just doesn't fit into a neat, tidy spot.
jsdoc in its various incarnations and some of its spawn like yuidoc take the approach that "what is good for Java is good for JavaScript". All these flavors are based on javadoc formatting, and have been in use for some time.
Aside from the regimented markup being a bit odd to read (admit it, even Java developers don't love it), it suffers from an inflexibility with regard to all the coding patterns available with JavaScript. Basically, it fails due for the same reason that all JavaScript libraries which attempt to subvert JavaScript's natural object model fail. These solutions, while influential in the idea that some form consistent coding approach could help us make better code, are not in the spirit of embracing JavaScript.
Why then do so many developers continue to use a documentation tool which was born of the same well-meaning yet misguided logic of "let's pretend JavaScript is Java"?
Excellent effort, but complex to set up and also tries to make a regimented system for documenting source code. It is extendable, but again, we have a documentation solution which is trying to force JavaScript into a more limited set of features.
jo uses a variant on this OOP pattern quite extensively for notifications between objects.
When you think about JavaScript, most of the interesting things that happen are asynchronous: XHR calls, loading scripts, accessing at database, making device-specific system calls; even user interactions are all asynchronous in nature.
Instead of trying to hide from this often complex-looking stuff, jo embraces it and provides a scheme to wrap all these different use cases in a consistent interface using joSubject.
This excellent, lightweight mobile application library by Nitobi neutralizes device differences and provides a stable webkit application shell. Jo is designed to work with PhoneGap out of the box, and it's highly recommended.
Another tool by Nitobi, LawnChair is a client-side storage solution which stores JSON objects (in SQLite or whatever the device supports). It looks promising, and the jo core has a special subclass of joDataSource called joLawn which folds Nitobi's library into the Jo event model.
jo makes extensive use of CSS for its widgets. As a result, it's extremely easy to skin and adapt your user interface for different devices. The project will have a community-driven theme collection to help reduce development time by choosing a stylesheet that most closely matches your application (or device native controls).
One feature jo exploits is the fact that modern browser engines treat unknown
tags as -- tags. So instead of mucking up your application's DOM and CSS space with
a horde of div
tags with different CSS classes, it uses namespaced tags which
are outside of your document's typical CSS name space (except body
).
<jocard>
<jotitle>My title</jotitle>
<jogroup>
<jolabel>Username</jolabel>
<input type="text">
<jodivider></jodivider>
<jobutton>Save</jobutton>
</jogroup>
</jocard>
One side benefit of this is that it is possible to load styled HTML content from another source and not have that content's CSS corrupt your application's user interface.
Bottom line here is the special UI controls you add with Jo can coexist with your standard HTML content-driven tags without undue CSS headaches.
See joInterface and joView for more uses of direct HTML and DOM nodes which are common for all UI elements.
Singleton which the framework uses to store global infomation. It also is responsible for initializing the rest of the framework, detecting your environment, and notifying your application when jo is ready to use.
load()
This method should be called after your DOM is loaded and before your app uses
jo. Typically, you can call this function from your document's onLoad
method,
but it is recommended you use more device-specific "ready" notification if
they are available.
getPlatform()
Returns the platform you're running in as a string. Usually this is not needed, but can be useful.
getVersion()
Returns the version of jo you loaded in the form of a string (e.g. 0.1.1
).
matchPlatform(string)
Feed in a string list of desired platforms (e.g. "mozilla chrome ipad"
),
and returns true if the identified platform is in the test list.
loadEvent
unloadEvent
These events are fired after jo loads or unloads, and can be used in your application to perform initialization or cleanup tasks.
jo extends the Function object to add a few goodies which augment JavaScript in a farily non-intrusive way.
extend(superclass, prototype)
Gives you an easy way to extend a class using JavaScript's natural prototypal inheritance. See Class Patterns for more information.
bind(context)
Returns a private function wrapper which automagically resolves context
for this
when your method is called.
This is a standard DOM element for JavaScript. Most of the jo views, continers and controls deal with these so your application doesn't need to.
Not a complete list by any means, but the useful ones for our purposes are:
appendChild(node)
insertChild(before, node)
removeChild(node)
jo uses these properties quite a bit:
innerHTML
className
style
A singleton which makes it easy to setup deferred object creation and cached results. This is a performance menchanism initially designed for UI views, but could be extended to handle data requests and other object types.
set(key, call, context)
Defines a factory (call
) for building an object keyed from the key
string.
The context
argument is optional, but provides a reference for this
.
get(key)
Returns an object based on the key
string. If an object has not been created
which corresponds to the key
, joCache will call the constructor defined to
create it and store the reference for future calls to get()
.
Defining a view for on-demand use:
joCache.set("home", function() {
return new joCard([
new joTitle("Home"),
new joMenu([
"Top Stories",
"Latest News",
"Old News",
"No News"
])
]);
});
Displaying a view later:
mystack.push(joCache.get("home"));
// the first call to get() will instantiate
// the view, subsequent calls will return the
// view that was created the first time
// you can pass parameters into your view factory
var x = joCache.get("home", "My Title");
// note that if you want to use joCache to cache
// views which differ based on parameters passed in,
// you probably want your own caching mechanism instead.
Class which strings asyncronous calls together.
In serious need of rework; doesn't meet original goal of sequencing these calls. This class might also become deprecated.
add(Function, context, data)
start()
stop()
next()
Singleton which abstracts the system clipboard. Note that this is a platform dependant interface. By default, the class will simply store the contents in a special joPreference named "joClipboardData" to provide clipboard capabilities within your app.
Even if you think you're just going to use the default behavior, it is recommended that you never manipulate the "joClipboardData" preference directly.
get()
set(String)
Low level methods which use just strings. At this time, you will need to stringify your own data when setting, and extract your data when getting.
cut(joControl)
copy(joControl)
paste(joControl)
High level methods which work with any joControl or subclass. If a control
supports selections, cut()
will automatically remove the selection after
copying its contents. Otherwise, cut()
will work the same as copy()
.
Note: this is not working yet, steer clear (or contribute some working code!)
Singleton with utility methods for manipulating DOM elements.
get(id)
Returns an HTMLElement which has the given id or if the id is not a string returns the value of id.
create(type, style)
Type is a valid HTML tag type. Style is the same as setStyle()
method. Returns an HTMLElement.
// simple
var x = joDOM.create("div", "mycssclass");
// more interesting
var x = joDOM.create("div", {
id: "name",
className: "selected",
background: "#fff",
color: "#000"
});
setStyle(tag, style)
Style can be an object literal with style information (including "id" or "className") or a string. If it's a string, it will simply use the style string as the className for the new element.
Note that the preferred and most cross-platform method for working
with the DOM is to use className
and possibly id
and put your
actual style information in your CSS file. That said, sometimes it's
easier to just set the background color in the code. Up to you.
getParentWithin(node, ancestor)
Returns an HTMLElement which is the first child of the ancestor which is a parent of a given node.
addCSSClass(HTMLElement, classname)
Adds a CSS class to an element unless it is already there.
removeCSSClass(HTMLElement, classname)
Removes a CSS class from an element if it exists.
toggleCSSClass(HTMLElement, classname)
Auto add or remove a class from an element.
pageOffsetLeft(HTMLElement)
and pageOffsetHeight(HTMLElement)
Returns the "true" left and top, in pixels, of a given element relative to the page.
applyCSS(css, stylenode)
Applies a css
string to the app. Useful for quick changes, like backgrounds
and other goodies. Basically creates an inline <style>
tag. This method
returns a reference to the new <style>
tag, which you can use with removeCSS()
and subsequent calls to applyCSS()
as the stylenode
argument.
loadCSS(filename)
Works the same as applyCSS()
but loads the CSS from a file instead of a string.
removeCSS(stylenode)
Removes a <style>
tag created with applyCSS()
or loadCSS()
.
Singleton with DOM event model utility methods. Ideally, application-level code shouldn't have to use this, but library code does.
on(HTMLElement, event, Function, context, data)
Set a DOM event listener for an HTMLElement which calls a given Function
with an optional context for this
and optional static data. Returns a
reference to the handler function, which is required if you need to remove()
later.
capture(HTMLElement, event, function, context, data)
This is the same os on()
, but captures the event at the node before its
children. If in doubt, use on()
instead.
remove(HTMLElement, event, handler)
Removes a previously declared DOM event. Note that handler
is the return
value of the on()
and capture()
methods.
stop(event)
Stop event propogation.
preventDefault(event)
Prevent default action for this event.
block(event)
Useful for preventing dragging the window around in some browsers, also highlighting text in a desktop browser.
getTarget(event)
Returns the HTMLElement which a DOM event relates to.
Wrapper for console.log()
(or whatever device-specific logging you have). Also could
be extended to send log information to a RESTful service as well, handy for devices
which don't have decent logging abilities.
It's an all-in-one utility that's smart enough to ferret out whatever you throw at it and display it in the console.
joLog("x=", x, "listdata=", listdata);
Basically, fill it up with strings, variables, objects, arrays and the function will produce a string version of each argument (where appropriate; browser debuggers tend to display objects nicely) in the same console line. Simple, effective, easy to use.
Class for custom events using the Observer Pattern. This is designed to be used inside a subject to create events which observers can subscribe to. Unlike the classic observer pattern, a subject can fire more than one event when called, and each observer gets data from the subject. This is very similar to YUI 2.x event model.
You can also "lock" the notification chain by using the capture()
method, which
tells the event to only notify the most recent subscriber (observer) which requested
to capture the event exclusively.
subscribe(Function, context, data)
Both context
and data
are optional. Also, you may use the Function.bind(this)
approach instead of passing in the context
as a separate argument.
All subscribers will be notified when the event is fired.
unsubscribe(Function, context)
Does what you'd think. The context
is only required if you used one when
you set up a subscriber.
capture(Function, context, data)
Only the last subscriber to capture this event will be notified until it is
released. Note that you can stack capture()
calls to produce a modal event
heiarchy. Used in conjunction with the resume()
method, you can build an
event chain where each observer can fire the next based on some decision making.
release(Function, context)
Removes the most recent subscription called with capture()
, freeing up the next
subscribers in the list to be notified the next time the event is fired.
fire(data)
Calls subscriber methods for all observers, and passes in: data
from the subject,
a reference to the subject
and any static data
which was passed in the
subscribe()
call.
resume(data)
If you used capture()
to subscribe to this event, you can continue notifying
other subscribers in the chain with this method. The data
parameter, as in
fire()
, is optional.
// inside the Subject, we setup an event observers can subscribe to
this.changeEvent = new joSubject(this);
// to fire the event inside the Subject
this.changeEvent.fire(somedata);
// simple case, using Function.bind()
somesubject.changeEvent.subscribe(this.mymethod.bind());
// explicit context (this)
somesubject.changeEvent.subscribe(this.mymethod, this);
// optional data which gets passed with the event fires
somesubject.changeEvent.subscribe(this.mymethod, this, "hello");
This is a very flexible way to handle messages between objects. Each subject may have multiple events which any number of observer objects can subscribe to.
Time utility functions. More will be added, but only as needed by the framework. There are entire libraries dedicated to extensive datetime manipulation, and Jo doesn't pretend to be one of them.
timestamp()
Returns a current timestamp in milliseconds from 01/01/1970 from the system clock.
SEC
, MIN
, HOUR
, DAY
Convenience global constants which make it easier to manipulate timestamps.
var twoHoursLater = joTime.timestamp() + (HOUR * 2);
Utility function which calls a given method within a given context after n
milliseconds with optional static data.
joDefer(Function, context, delay, data);
Note that delay defaults to 100ms if not specified, and data
is optional.
Deprecated, use joDefer instead.
Wrapper class for WebKit SQLite database.
open(datafile, size)
datafile
is a filename, size
is an optional parameter for initial
allocation size for the database.
close()
now()
Deprecated convenience method which returns a SQLite-formatted date string for use in queries. Should be replaced with a utility function in joTime.
Wraps data acquisition in an event-driven class. Objects can
subscribe to the changeEvent
to update their own data.
This base class can be used as-is as a data dispatcher, but is designed to be extended to handle asynchronous file or SQL queries.
set()
get()
clear()
setQuery(...)
getQuery()
load()
refresh()
changeEvent
errorEvent
Under construction, use with care.
A special joDataSource which loads and handles a file. This class wraps joFile.
A utility method which uses XMLHttpRequest to load a text-like file from either a remote server or a local file.
Note that some browsers and mobile devices will not allow you to load from just any URL, and some will restrict use with local files especially (I'm looking at you, FireFox).
If your aim is to load JavaScript-like data (also, JSON), you may want to look at joScript instead, which uses script tags to accomplish the job.
joFile(url, call, context, timeout)
url
is a well-formed URL, or, in most cases, a relative url to a local
file
call
is a function to call when the operation completes
context
is an optional scope for the function to call (i.e. value of this
).
You can also ignore this parameter (or pass in null
and use Function.bind(this)
instead.
timeout
is an optional parameter which tells joFile to wait, in seconds,
for a response before throwing an error.
// simple call with a global callback
var x = joFile("about.html", App.loadAbout);
// an inline function
var y = joFile("http://joapp.com/index.html", function(data, error) {
if (error) {
console.log("error loading file");
return;
}
console.log(data);
});
A class used for storing and retrieving preferences in your application.
The interface for this is changing. joPreference will become a specialized application-level extension of joRecord in the near future. Until then, you should use joRecord to achieve this use-case.
An event-driven wrapper for an object and its properties. Useful as a data interface for forms and other collections of UI controls.
link(property)
Returns a reference to a joProperty object which can be used with UI controls (children of joControl) to automatically save or load data based on user interaction.
save()
Saves the object's data. The base class does not itself save the data;
you will need to make your own action for the save method, or have
something which subscribes to the saveEvent
.
load()
Loads the object's data, and fires off notifications to any UI controls
which are linked to this joRecord object. Same as the save()
method,
you will have to make this function do some actual file loading if that's
what you want it to do.
getProperty(property)
setProperty(property, value)
Get or set a given property. Used in conjunction with setAutoSave()
,
setProprty()
will also trigger a call to the save()
method.
getDelegate(property)
Returns a reference to the joProperty object which fires off events
for data changes for that property. If none exists, one is created.
This method is used by the link()
method, and can be overriden if
you extend this class to provide some other flavor of a joDataSource
to manage events for your properties.
// setup a joRecord
var r = new joRecord({
user: "Jo",
password: "1234",
active: true
});
// bind it to some fields
var x = new joGroup([
new joLabel("User"),
new joInput(r.link("user")),
new joLabel("Password"),
new joPasswordInput(r.link("password")),
new joFlexBox([
new joLabel("Active"),
new joToggle(r.link("active"))
])
]);
And if you want the data to be persistent, or interact with some cloud service, you'll need to do something like this:
// make something happen to load the data
r.load = function() {
// some AJAX or SQL call here
};
// make something happen to save the data
r.save = function() {
// some AJAX or SQL call here
};
You could also make your own subclass of joRecord with your own save
and load methods using extend()
like this:
var preferences = function() {
// call to the superclass constructor
joRecord.apply(this, arguments);
};
preferences.extend(joRecord, {
save: function() {
// do an AJAX or SQL call here
},
load: function() {
// do an AJAX or SQL call here
}
}
See Class Patterns for more details on this method of "subclassing" in JavaScript.
Used by joRecord to provide an event-driven binding to properties. This class is instantiated by joRecord and not of much use on its own.
See joRecord for examples.
Script tag loader function which can be used to dynamically load script files or make RESTful calls to many JSON services (provided they have some sort of callback ability). This is a low-level utility function.
Need a URL with some examples of this.
joScript(url, callback, context, errorcallback, errorcontext)
this
, and is optional)Calls your handler method and passes a truthy value if there was an error.
joScript("myscript.js", function(error, url) {
if (error)
console.log("script " + url + " didn't load.");
}, this);
SQL flavor of joDataSource which uses "HTML5" SQL found in webkit.
setDatabase(joDatabase)
setQuery(query)
setParameters(arguments)
execute(query, arguments)
changeEvent
Fired when data is loaded after an execute()
or when data is cleared.
errorEvent
Fired when some sort of SQL error happens.
A joDataSource geared for YQL RESTful JSON calls. YQL is like SQL, but for cloud services. Pretty amazing stuff:
The Yahoo! Query Language is an expressive SQL-like language that lets you query, filter, and join data across Web services. With YQL, apps run faster with fewer lines of code and a smaller network footprint.
Yahoo! and other websites across the Internet make much of their structured data available to developers, primarily through Web services. To access and query these services, developers traditionally endure the pain of locating the right URLs and documentation to access and query each Web service.
With YQL, developers can access and shape data across the Internet through one simple language, eliminating the need to learn how to call different APIs.
A simple one-shot use would look like:
// setup our data source
var yql = new joYQL("select * from rss where url='http://davebalmer.wordpress.com'");
// subscribe to load events
yql.loadEvent.subscribe(function(data) {
joLog("received data!");
});
// kick off our call
yql.exec();
A more robust example with parameters in the query could look something like this:
// quick/dirty augmentation of the setQuery method
var yql = new joYQL();
yql.setQuery = function(feed, limit) {
this.query = "select * from rss where url='"
+ feed + "' limit " + limit
+ " | sort(field=pubDate)";
};
// we can hook up a list to display the results
var list = new joList(yql).attach(document.body);
list.formatItem = function(data, index) {
var html = new joListItem(data.title + " (" + data.pubDate + ")", index);
};
// later, we make our call with our parameters
yql.exec("http://davebalmer.wordpress.com", 10);
setQuery()
Designed to be augmented, see the example above.
exec()
The idea here is to make a generic "spinner" control which you can overlay on other controls. It's still in flux, don't use it just yet.
setMessage(status)
You can update the status message in this busy box so users have a better idea why the busy box is showing.
Button control.
// simple invocation
var x = new joButton("Done");
// optionally pass in a CSS classname to style the button
var y = new joButton("Cancel", "cancelbutton");
// like other controls, you can pass in a joDataSource
// which could be useful, so why not
var z = new joButton(joPreference.bind("processname"));
Basically, a paragraph of text.
Special container for card views, more of an application-level view.
activate()
deactivate()
These methods are called automatically by various joView objects, for now joStack is the only one which does. Basically, allows you to add application-level handlers to initialize or cleanup a joCard.
DEPRECATED use joInterface instead. This function is planned to die when jo goes beta.
A view which is designed to contain other views and controls. Subclass to provide different layout types. A container can be used to intantiate an entire tree of controls at once, and is a very powerful UI component in jo.
// plain container
var x = new joContainer();
// HTML or plain text
var y = new joContainer("Some HTML");
// HTMLElement
var w = new joContainer(joDOM.get("mydiv"));
// nested inline structure with text, HTML, joViews or HTMLElements
var z = new joContainer([
new joTitle("Hello"),
new joList([
"Red",
"Green",
"Blue"
]),
new joFieldset([
"Name", new joInput(joPreference.bind("name")),
"Phone", new joInput(joPreference.bind("phone"))
]),
new joButton("Done")
]);
// set an optional title string, used with joNavbar
z.setTitle("About");
changeEvent
setData(data)
The constructor calls this method if you provide data
when you instantiate
(see example above)
push(data)
Same support as setData()
, but places the new content at the end of the
existing content.
setTitle(string)
getTitle(string)
Titles are optional, but used with joStack & joStackScroller to update a joNavbar control automagically.
Interactive, data-driven control class which may be bound to a joDataSource, can receive focus events, and can fire off important events which other objects can listen for and react to.
changeEvent
selectEvent
setValue(value)
Many controls have a value in addition to their data. This is
particularly useful for joList
, joMenu
, joOption
and other controls
which has a list of possibilities (the data) and a current seletion from those
(the value).
enable()
disable()
Enable or disable the control, pretty much does what you'd expect.
focus()
blur()
Manually control focus for this control.
setDataSource(joDataSource)
Tells this control to bind its data to any joDataSource
or subclass.
setValueSource(joDataSource)
Tells this control to bind its value to any joDataSource
type.
setReadOnly(state)
Certain controls can have their interaction turned off. State is either true
or false
.
This is a higher level container that wraps a joPopup with a joShim.
Simple visual divider.
A compound UI element which allows the user to hide/show its contents. The first object passed in becomes the trigger control for the container, and the second becomes the container which expands and contracts. This action is controlled in the CSS by the presence of the "open" class.
This is a typical pattern:
// normal look & feel
var x = new joExpando([
new joExpandoTitle("Options"),
new joExpandoContent([
new joLabel("Label"),
new joInput("sample field")
])
]);
Note that joExpando doesn't care what sort of controls you tell it to use. In this example, we have a joButton that hides and shows a DOM element:
// you can use other things though
var y = new joExpando([
new joButton("More..."),
joDOM.get("someelementid")
]);
open()
close()
toggle()
openEvent
closeEvent
New widget to contain expando contents. This is normally used with joExpando, but not required.
Common UI element to trigger a joExpando. Contains a stylable arrow image which indicates open/closed state.
See joExpando use.
Uses the flexible box model in CSS to stretch elements evenly across a row.
// a simple row of things
var x = new joFlexrow([
new joButton("OK"),
new joButton("Cancel")
]);
// making a control stretch
var y = new joFlexrow(new joInput("Bob"));
Uses the flexible box model in CSS to stretch elements evenly across a column.
// fill up a vertical space with things
var x = new joFlexcol([
new joNavbar(),
new joStackScroller()
]);
Singleton which manages global input and event focus among joControl objects.
set(joControl)
Unsets focus on the last control, and sets focus on the control passed in.
clear()
Unsets focus on the last control.
refresh()
Sets focus back to the last control that was focused.
Attempt to make a filler object which pushed subsequent joView objects further down in the container if possible (to attach its contents to the bottom of a card, for eaxmple).
This behavior requires a working box model to attach properly to the bottom of your container view.
Experimental global gesture handler (keyboard, dpad, back, home, flick?). This needs a lot more fleshing out, so it's not (quite) ready for general consumption.
upEvent
downEvent
leftEvent
rightEvent
backEvent
forwardEvent
homeEvent
closeEvent
activateEvent
deactivateEvent
Note that the events setup here are for the browser or webOS. The
setEvents
method most likely needs to change based on which OS you're running, although looking more deeply into PhoneGap event layer.
Group of controls, purely visual.
A simple HTML content control. One interesting feature is it intercepts all
<a>
tag interactions and fires off a selectEvent
with the contents of
the tag's href
property.
This is a relatively lightweight approach to displaying arbitrary HTML data inside your app, but it is not recommended you allow external JavaScript inside the HTML chunk in question.
Also keep in mind that your app document already has <html>
, <head>
and
<body>
tags. When you use the setData()
method on this view, make sure
you don't use any of these tags to avoid weird issues.
In a future version, it is feasible to load in stylesheets references in the HTML document's
<head>
section. For now, that entire can of worms will be avoided, and it's left up to you, the developer, to load in any required CSS files usingjoDOM.loadCSS()
.
// simple html string
var x = new joHTML("<h1>Hello World!</h1><p>Sup?</p>");
// use a joDataSource like a file loader
var y = new joHTML(new joFileSource("sample.html"));
Single-line text input control. When you instantiate or use setData()
, you can
either pass in an initial value or a reference to a joDataSource object which it,
like other joControl instances, will bind to.
// simple value, simple field
var x = new joInput(a);
// set up a simple joRecord instance with some default data
var pref = new joRecord({
username: "Bob",
password: "password"
});
// attach the value to a data structure property
var y = new joInput(pref.link("username"));
focus()
blur()
You can manually set focus or call the blur()
method (which also
triggers a data save).
setData()
Pass in either some arbitrary value for the control, or a reference to a joDataSource if you want to automatically bind to a storage system (e.g. joPreference).
EXPERIMENTAL
This utility method is experimental! Be very careful with it. NOTE that for now, this class requires you to remove whitespace in your HTML. If you don't know a good approach offhand to do that, then this thing probably isn't ready for you yet.
This class parses the DOM tree for a given element and attempts to
attach appropriate joView subclasses to all the relevant HTML nodes.
Returns an object with references to all elements with the id
attribute set. This method helps turn HTML into HTML + JavaScript.
// an HTML element by its ID
var x = new joInterface("someid");
// a known HTML element
var y = new joInterface(someHTMLElement);
// the entire document body (careful, see below)
var z = new joInterface();
A new object with a property for each element ID found. For example:
<!-- this DOM structure -->
<jocard id="login">
<jotitle>Login</jotitle>
<jogroup>
<jolabel>Username</jolabel>
<input id="username" type="text">
<jolabel>Password</jolabel>
<input id="password" type="password">
</jogroup>
<jobutton id="loginbutton">Login</jobutton>
</jocard>
Parsed with this JavaScript:
// walk the DOM, find nodes, create controls for each
var x = new joInterface("login");
Produces these properties:
x.login
is a reference to a new joCard
x.username
is a reference to a new joInput
x.password
is a reference to a new joPassword
x.loginbutton
is a reference to a new joButton
This in essence flattens your UI to a single set of properties you can use to access the controls that were created from your DOM structure.
In addition, any unrecognized tags which have an id
attribute set will
also be loaded into the properties.
Yes, you can make a joInterface that encapsulates your entire UI with HTML. This is not recommended for larger or more complex applications, some reasons being:
Rendering speed: if you're defining multiple views within a <jostack>
(or another subclass of joContainer), your users will see a flicker and
longer load time while the window renders your static tags and the extra
views for the stack are removed from view.
Double rendering: again with <jostack>
tags, you're going to see a separate
render when the first view is redrawn (has to).
Load time: especially if you're doing a mobile app, this could be a biggie. You are almost always going to be better off building the app controls with JavaScript (especially in conjunction with joCache, which only creates DOM nodes for a given view structure on demand).
If you really want to use HTML as your primary means of defining your UI, you're
better off putting your major UI components inside of a <div>
(or other tag)
with display: none
set in its CSS property. Like this:
<!-- in your CSS: .hideui { display: none } -->
<div class="hideui" id="cards">
<jocard id="about">
<jotitle>About this app</jotitle>
<johtml>
This is my app, it is cool.
</johtml>
<jobutton>Done</jobutton>
</jocard>
<jocard id="login">
... etc ...
</jocard>
</div>
Then in your JavaScript:
// pull in all our card views from HTML
var cards = new joInterface("cards");
Definitely use this class judiciously or you'll end up doing a lot of recatoring as your application grows.
This is both good and bad, depending on your coding style and complexity of your app. Because all the tags with an ID attribute (regardless of where they are in your tag tree) get a single corresponding property reference, things could get very messy in larger apps. Again, be smart.
Label view, purely a visual presentation. Usually placed in front of input fields and other controls.
A widget class which expects an array of any data type and renders the array as a list. The list control handles DOM interactions with only a single touch event to determine which item was selected.
selectEvent
Fired when an item is selected from the list. The data in the call is the index of the item selected.
changeEvent
Fired when the data is changed for the list.
formatItem(data, index)
When subclassing or augmenting, this is the method responsible for rendering a list item's data.
compareItems(a, b)
For sorting purposes, this method is called and should be overriden to support custom data types.
// general logic and approriate return values
if (a > b)
return 1;
else if (a == b)
return 0;
else
return -1
setIndex(index)
getIndex()
DEPRECATED USe setValue()
and getValue()
instead, see joControl.
refresh()
setDefault(message)
Will present this message (HTML string) when the list is empty. Normally the list is empty; this is a convenience for "zero state" UI requirements.
getNodeData(index)
getLength()
next()
prev()
setAutoSort(boolean)
Simple menu class with optional icons.
setData(menudata)
See the example below for the format of the menu data.
// simple inline menu; you can always setup the menu items (or change
// them) but using the `setData()` method, same as any joView
var menu = new joMenu([
{ title: "About" },
{ title: "Frequently Asked Questions", id: "faq" },
{ title: "Visit our website", id: "visit", icon: "images/web" }
]);
// simple inline function event handler
menu.selectEvent.subscribe(function(id) {
switch (id) {
case "0":
// the "About" line; if no id, the index of the menu item is used
stack.push(aboutCard);
break;
case "faq":
stack.push(faqCard);
break;
case "visit":
stack.push(visitCard);
break;
}
});
This could actually be called "more consistent and simple" use. If your menus
are static, you could always setup an id-based dispatch delegate which pushes
the appropriate card based on the menu id
selected.
You could use the id
in conjunction with view keys you create with joCache.
The handler would then be something like:
menu.selectEvent.subscribe(function(id) {
mystack.push(joCache.get(id));
});
Floating navigation control. Usually tied to a joStack or joStackScroller. Will handle display of a "back" button (controllable in CSS) and show the title string of the current view in a stack (if it exists).
// make a stack
var stack = new joStackScroller();
// new navbar
var x = new joNavbar();
// link to a stack
x.setStack(stack);
back()
Signals the associated stack to move back in its stack (i.e. calls
the stack's pop()
method).
setStack(joStack or joStackScroller)
Links this control to a stack.
A "back" button, which can be made to be shown only in appropriate platforms (e.g. iOS, Safari, Chrome) through CSS styling.
See joNavbar for more information.
This controls lets the user select one of a few options. Basically, this is a menu with a horizontal layout (depending on your CSS).
// simple set of options
var x = new joOption([
"Red",
"Blue",
"Green"
]);
// set the current value
x.setValue(2);
// or, associate the value with a joRecord property
var pref = new joRecord();
var y = new joOption([
"Orange",
"Banana",
"Grape",
"Lime"
], pref.link("fruit"));
// you can even associate the list with a datasource
var fruits = new joDataSource( ... some query stuff ...);
var z = new joOption(fruits, pref.link("fruit"));
Secret data input field (e.g. displays ******
instead of secret
).
Note that this requires CSS3 which is known not to be currently supported in Opera or Internet Explorer.
A simple popup control. Pass in the UI contents as you would any other subclass of joContainer (e.g. joCard).
show()
hide()
These do what you'd expect.
showEvent
hideEvent
Abstraction layer for the device screen. Uses document.body as its DOM element and allows other controls to be nested within (usually a joStack or other high-level containers or controls).
alert(title, message, buttons)
Simple alert box. The buttons
parameter is optional; a simple
"OK" button is added if nothing is specified.
showPopup(joView)
hidePopup(joView)
These methods allow you to do a completely custom modal joPopup. Pass in either a joView, an array of them, or and HTMLElement or a string, the same as you would when you create a joCard or other child of joContainer.
var x = new joScreen([
new joNav(),
new joStack(),
new joToolbar()
]);
// show a simple alert dialog
x.alert("Hello", "This is an alert");
// a more complex alert
x.alert("Hola", "Do you like this alert?", [
{ label: "Yes", action: yesFunction, context: this },
{ label: "No", action: noFunction, context: this }
]);
// a completely custom popup
x.showPopup(myView);
resizeEvent
menuEvent
activateEvent
deactivateEvent
backEvent
forwardEvent
A scroller container. Ultimately, mobile webkit implementations
should properly support scrolling elements that have the CSS
overflow
property set to scroll
or auto
. Why don't they,
anyway? Until some sanity is adopted, we need to handle this scrolling
issue ourselves. joScroller expects a single child to manage
scrolling for.
// make a scroller and set its child later
var x = new joScroller();
x.setData(myCard);
// or define things inline, not always a good idea
var y = new joScroller(new joList(mydata));
// you can dump a big hunk of HTML in there, too
// since jo wraps strings in a container element, this works
var z = new joScroller('Some giant HTML as a string');
scrollBy(position)
scrollTo(position or joView or HTMLElement)
Scrolls to the position or the view or element. If you specify an element or view, make sure that element is a child node, or you'll get interesting results.
setScroll(horizontal, vertical)
Tells this scroller to allow scrolling the vertical, horizontal, both or none.
// free scroller z.setScroll(true, true);
// horizontal z.setScroll(true, false);
// no scrolling z.setScroll(false, false);
Multi-select control which presents a set of options for the user to choose from.
setValue(value)
Set the current value, based on the index for the option list.
getValue()
Returns the index of the current selected item.
field
Reference to the value field for this control.
list
Reference to the joSelectList for this control.
// pass in an array of options
var x = new joSelect([ "Apples", "Oranges", "Grapes" ]);
// pass in a current value
var y = new joSelect([ "Apples", "Oranges", "Grapes" ], 2);
// respond to the change event
y.changeEvent = function(value, list) {
console.log("Fruit: " + list.getNodeValue(value));
});
joSelect flavor of joExpandoTitle.
A selection list of options used by joSelect.
A simple screen dimmer. Used mostly for popups and other modal use cases.
show()
hide()
These do what you'd expect.
showEvent
hideEvent
Slider control, horizontal presentation (may be extended later to allow for vertical and x/y).
setRange(min, max, snap)
Where min
/max
is a number, either integer or decimal, doesn't matter. If max
and min
are integers, then snap
defaults to 1
, otherwise it is set to 0
(no
snap, which allows free movement).
The optional snap
value adjusts the granularuty of choices. Set to 0
for
free-floating, or any other positive number. Any snap
that is less than 0
or greater than the total range of possible values will be ignored.
// basic slider, will allow any decimal value
// between 0 and 1, defaults to 0
var x = new joSlider();
// custom range and default value set
var y = new joSlider(0).setRange(-10, 10);
// percent slider, with 5% snap
var z = new joSlider(0).setRange(0, 100, 5);
// responding to change events
var r = new joSlider().changEvent.subscribe(function(value) {
console.log(value);
}, this);
Play preloaded sound effects using the HTML5 Audio
object. This module could
be wildly different for various platforms. Be warned.
play()
pause()
rewind()
stop()
Basic sound controls.
setLoop(n)
Tell the joSound to automatically loop n
times. Set to -1
to loop
continuously until pause()
.
setVolume(level)
Level is a decimal value from 0
to 1
. So, half volume would be 0.5
.
endedEvent
errorEvent
A UI container which keeps an array of views which can be pushed and popped.
The DOM elements for a given view are removed from the DOM tree when popped so we keep the render tree clean.
push(joView | HTMLElement)
Pushes a new joView (or HTMLELement) onto the stack.
pop()
Pulls the current view off the stack and goes back to the previous view.
home()
Return to the first view, pop everything else off the stack.
show()
hide()
Controls the visibility of the entire stack.
forward()
back()
Much like your browser forward and back buttons, only for the stack.
setLocked(boolean)
The setLocked()
method tells the stack to keep the first view pushed onto the
stack set; that is, pop()
won't remove it. Most apps will probably use this,
so setting it as a default for now.
showEvent
hideEvent
homeEvent
pushEvent
popEvent
Should set classNames to new/old views to allow for CSS transitions to be set (swiping in/out, cross fading, etc). Currently, it does none of this.
Also, some weirdness with the new forward()
and back()
methods in conjuction
with push()
-- need to work on that, or just have your app rigged to pop()
on back to keep the nesting simple.
What happens when you mix joStack and joScroller? You get this class. Use exactly as you would joStack, only it automatically puts a scroller in the stack as needed. At some point, this might get folded into joStack, but for now it's a special class.
It also handles the scrollTo()
and scrollBy()
methods from
joScroller.
Tab bar widget.
Data is expected to be an array of { type: "", label: ""}
objects,
in the display order for the bar.
Table control, purely visual representation of tabular data (usually an array of arrays).
// simple table with inline data
var x = new joTable([
["Nickname", "Phone", "Email"],
["Bob", "555-1234", "bob@bobco.not"],
["Jo", "555-3456", "jo@joco.not"],
["Jane", "555-6789", "jane@janeco.not"]
]);
// we can respond to touch events in the table
x.selectEvent.subscribe(function(index, table) {
// get the current row and column
joLog("Table cell clicked:", table.getRow(), table.getCol());
// you can also get at the cell HTML element as well
joDOM.setStyle(table.getNode(), { fontWeight: "bold" });
});
setCell(row, column)
Sets the active cell for the table, also makes it editiable and sets focus.
getRow()
, getCol()
Return the current row or column
Multi-line text input control. When you instantiate or use setData()
, you can
either pass in an initial value or a reference to a joDataSource object which it,
like other joControl instances, will bind to.
Basically, this is just a multi-line version of joInput.
// simple multi-line field
var sample = "This is some sample text to edit.";
var x = new joTextarea(sample);
// setting the style inline using chaining
var f = new joTextarea(sample).setStyle({
minHeight: "100px",
maxHeight: "300px"
});
// adding a simple change event handler using chaining
var h = new joTextarea(sample).changeEvent.subscribe(function(data) {
joLog("text area changed:", data);
});
// attach the value to a preference
var y = new joTextarea(joPreference.bind("username"));
// attach input control to a custom joDataSource
var username = new joDataSource("bob");
var z = new joTextarea(username);
Title view, purely a visual presentation.
Boolean widget (on or off).
setLabels(Array)
You can change the labels for this control, which default to "Off" and "On".
// simple
var x = new joToggle();
// with value
var y = new joToggle(true);
// with custom labels
var z = new joToggle().setLabels(["No", "Yes"]);
See Data Driven Controls for more examples.
Locks UI controls to the bottom of whatever you put this container into.
Base class for all other views, containers, controls and other visual doo-dads.
var x = new joView(data);
Where data
is either a text or HTML string, an HTMLElement, or any joView object
or subclass.
setData(data)
getData()
createContainer(type, classname)
setContainer(HTMLElement)
getContainer()
clear()
refresh()
attach(HTMLElement or joView)
detach(HTMLElement or joView)
Convenience methods which allow you to append a view or DOM node to the current view (or detach it).
Copyright 2010 Dave Balmer, Jr. All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY DAVE BALMER, JR. "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL DAVE BALMER, JR. OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
The views and conclusions contained in the software and documentation are those of the authors and should not be interpreted as representing official policies, either expressed or implied, of Dave Balmer, Jr.