Dynamic layout using angularjs (the angularjs way) - angularjs

Question

I just recently started tinkering with AngularJs, so my question is fairly basic. For concreteness's sake, let me start with the minimal setting: a page with banner, body and footer. The goal is to make banner and footer stay at the top and bottem of the page (css position: fixed) and the body will fill in the rest.
If I were to use jQuery, I could set position: fixed for body, and listen to window's resize event to determine where I should put my body.
Presumably, I could do the same in AngularJs. But I've read many places that one shouldn't try to manipulate the layout from the code, since it's not in the philosophy of AngularJs. So, what's the best way to achieve this in the AngularJs way? Thanks.

Answer 1

Dynamic layout usually refers to a layout that changes depending upon the current route. Routing is how AngularJS associates a URL with a Controller and data. It becomes an important part of an app once you go beyond just 1 page.
Multiple Views
If you use something like ui-router (http://angular-ui.github.io/ui-router/) it allows you to define views that can have child views.
In your example, the header, body and footer would all be child views of a parent view. Each view would have it's own template, controller and data. When routing changes you can have just one or more of those view change, while the other views remain the same.
Binding Events
You can do all the same event bindings in AngularJS as you can in jQuery. The difference is the life-cycle of those bindings.
If you bind to the click event for a directive using the directive's element, then you don't have to worry about that binding when the directive is destroyed. AngularJS will remove the binding automatically.
When you bind to something like the window.resize event, then you have to be more careful.
link: function($scope, $el, $attrs) {
// this doesn't have to be unbind
$el.bind('click',function(e) {
// do stuff
});
// this has to be unbind on destroy
angular.element($window).bind('resize.mybinding',function(e) {
// do stuff
});
$scope.$on('$destroy',function(){
angular.element($window).unbind('resize.mybinding');
});
});
I've seen a lot of AngularJS source code bind to window.resize when it wasn't necessary. Only you know when it's needed, but sometimes you can get away with just using a watcher.
link: function($scope, $el, $attrs) {
$scope.$watchGroup(function(){
return [$window.innerWidth,$window,innerHeight];
},function(values){
// do stuff
});
});
The above does the same thing as binding. It executes a closure function when the size of the window changes, but the difference is that it's triggered only during digest and not by the window resize event. This can sometimes be more efficient for performance. As the resize is relative to only when the directive is digested.
A lot of AngularJS applications use JavaScript code to manage the layout of an application. How much JavaScript code you use, and why you do it that way is up to you, but keeping layout separated from the JavaScript side has a lot of advantages. It's better to let CSS handle it.

Answer 2

Bootstrap provides a nice plug-in called Affix that does just that.
<div id="banner" data-spy="affix">Fixed Banner</div>
<div>Body</div>
<div id="footer" data-spy="affix">Fixed Footer</div>
More on affix here for example:
http://www.tutorialrepublic.com/twitter-bootstrap-tutorial/bootstrap-affix.php