AngularJS custom directives, how do you bind AND accept mouse events?

Question

I require a custom DOM element that accepts mouse clicks and whose state is dependant on the model:-

<card ng-repeat="card in cards" x="card.x"
    y="card.y" color="card.color" on-click="test_click('b')">
</card>

I am able to build a custom directive that binds to a controller's scope variables through its DOM attributes and use them to alter its view. I have this working by allowing the directive to inherit its parents scope:

app.directive('card', function ($timeout) {
    return {
        restrict:'E',
        link:function (scope, element, attrs) {
            element.addClass('card');

            element.click(function(){
                scope.onClick()
            });

            scope.$watch(attrs.x, function (x) {
                element.css('left', x + 'px');
            });
            scope.$watch(attrs.y, function (y) {
                element.css('top', y + 'px');
            });
            scope.$watch(attrs.color, function (color) {
                element.css('backgroundColor', color);
            });
        }
        /*
        ,scope:{
            x:'=',
            y:'=',
            color:'=',
            onClick: "&"
        }
        */
    };
});

I am able to get a mouse click event to propagate up to the controller by creating an isolated scope and doing some rewiring (by commenting the scope in above).

However, I am unable to get both behaviours working at the same time.

I presume I need to get the x variable bound to the attribute value, which is what I have tried to do. But even by trying every combination of syntax I can think of, I just can't seem to get it working.

Here is the complete case jsfiddle

Mark Rajcok · Accepted Answer · 2012-12-09 04:08:37Z

If I understand what you're trying to do, you can use ng-style instead of $watch()es, and ng-click instead of element.click():

<card ng-repeat="card in cards" ng-click="test_click('b')"
  ng-style="{left: card.x, top: card.y, 'background-color': card.color}" >

Fiddle

When we use any of the pre-built Angular directives -- e.g., ngStyle, ngRepeat, ngClass, ngSwitch, ngShow -- and tie them to models, Angular does the watch()ing for us.

(I don't understand why it only works if I include jQuery. I don't see any jQuery-specific methods being called.)

Update: I figured out how to make it work without jQuery -- add 'px' to the ng-style:

<card ng-repeat="card in cards" ng-click="test_click('b')
  ng-style="{left: card.x + 'px', top: card.y + 'px', 'background-color': card.color}" ">

Updated fiddle.

I guess jQuery is more forgiving somehow if we leave off the 'px'.

To the second fiddle, I also added a "move card #1 down 200px" ng-click/hyperlink, to prove that changing the model results in Angular automatically updating the view for us.

Tom Larkworthy · Accepted Answer · 2012-12-08 21:20:18Z

0

Ahhhhh, I had the correct approach, the watchers had broken though. Clearly I don't fully understand the semantics of $watch, as I am not totally understanding the solution. I only realised it by printing out the scope and detecting the right variables were present in the isolated scope case.

anyway, the solution: I changed the $watch calls to:-

scope.$watch("x", function (x) {
    element.css('left', scope.x + 'px');
});

and this tracked changes to the bound variables

answered Dec 8, 2012 at 21:20

Tom Larkworthy

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