I want to add a directive that will do something when an element class is changed.
My directive is:
(function (angular) {
angular.module('myApp')
.directive('myClassWatch', myClassWatch);
function myClassWatch() {
return {
restrict: 'A',
link: function (scope, element, attrs, controller) {
scope.$watch(function () {
return element.attr('class');
}, function (newValue, oldValue) {
debugger;
if(oldValue !== newValue)
console.log('class changed from ' + oldValue + ' to ' + newValue);
});
}
}
}
})(angular);
The html is:
<div class="top-icons-item popup-container popup-link-container" my-class-watch>
</div>
I do some actions elsewhere that toggles the class "open" in my div element - it is visible in the html - yet the debugger is never called (also no console logs of course). I can see that the link function is called on page load and the debugger also stops, but thats only on page load and not afterwards when I actually do actions that adds another class.
I have read several issued here before including Directive : $observe, class attribute change caught only once but I can't understand why I don't get the same result. What can I do to try check why this occures?
Update: The class change is made using jQuery not in a controller but in an old jquery watches code. May this be cause? could angular be unaware of class change when its not done from an angular code?
Wrap your jQuery code into $apply.
It similar to you are making changes to $scope out of angular context(jquery ajax, setTimeout, etc). Use $apply to make angular know about the changes done.
angular.element(document.getElementById('app')).injector().invoke(['$compile', '$rootScope', function($compile, $rootScope) {
$rootScope.$apply(function() {
//your jquery code goes here...
var a = document.getElementById('abc');
angular.element(a).addClass('hello');
});
}]);
Related
To start off, I know there are loads of similar questions but none that I found which supports execution of arbitrary methods with event listeners.
I have this directive which executes functions passed when the window resizes.
app.directive('onResize', function() {
var directive = {
'link': function(scope, element, attrs) {
var onResizeHandler = scope.$eval(attrs.onResize);
angular.element(window).on('resize', onResizeHandler);
angular.element(window).on('$destory', function() {element.off();});
}
};
return directive;
});
I can trigger the above directive with
<div data-on-resize="stickyHeader">...</div>
Which runs my method, inside my controller.
app.controller('myController', [$scope, function($scope) {
$scope.stickyHeader = function() {
console.log('event triggered')
};
}]);
All the above code works fine, but I need to pass some arguments to stickyHeader as in data-on-resize="stickyHeader(arg1, arg2)" When I try that, I get Cannot read property 'call' of undefined at ng (angular.js:3795) in the console. Not sure what I can do to make my directive support arbitrary methods with arguments.
The directive needs to evaluate the AngularJS expression defined by the on-resize attribute every time the events occurs:
app.directive('onResize', function($window) {
var directive = {
link: function(scope, elem, attrs) {
angular.element($window).on('resize', onResizeHandler);
scope.$on('$destroy', function() {
angular.element($window).off('resize', onResizeHandler);
});
function onResizeHandler(event) {
scope.$eval(attrs.onResize, {$event: event});
scope.$apply();
}
}
};
return directive;
});
Also since the resize event comes from outside the AngularJS framework, the event needs to be brought into the AngularJS execution context with $apply().
Further, to avoid memory leaks, the event handler needs to be unbound when the scope is destroyed.
Usage:
<div data-on-resize="stickyHeader($event)">...</div>
For more information, see AngularJS Developer Guide - $event.
http://jsfiddle.net/2dgzt18a/
I'm expecting the model on the parent to get updated when Enter is pressed in the input. But it does not. Output from console log looks promising, like it should do it. Do I need to use a $watch ? Doubt it, but thought I'd ask.
HTML
<div data-ng-app="testApp">
<div data-ng-controller="testCtrl">
<strong>{{pkey}}</strong>
<span data-test-directive
data-parent-item="pkey"
data-parent-update="update(pkey)"></span>
</div>
</div>
DIRECTIVE
var testApp = angular.module('testApp', []);
testApp.directive('testDirective', function ($timeout) {
return {
scope: {
key: '=parentItem',
parentUpdate: '&'
},
replace: true,
template: '<div><input type="text"></input></div>',
link: function(scope, elem, attrs) {
elem.bind('keydown keypress', function(event) {
if (event.which === 13) {
scope.parentUpdate({ pkey: 'D+' + scope.key});
event.preventDefault();
}
})
}
};
});
CONTROLLER
testApp.controller('testCtrl', function ($scope) {
$scope.pkey = 'golden';
$scope.update = function (k) {
// Expecting local variable k, or $scope.pkey to have been
// updated by calls in the directive's scope.
console.log('CTRL:', $scope.pkey, k);
$scope.pkey = 'C+' + k;
console.log('CTRL:', $scope.pkey);
};
});
I believe I have seen this work using a controller in a directive, but since I'm interested in a Keypress event, is why I need to use link.
elem.bind just binds js function to event, nothing else.
Add scope.$apply().
P.S. i.e. ng-click does nearly the same: binds event and call apply after callback.
P.S.1. If you can use more modern angular version - there are ng-keypress and similar directives.
scope.$apply is not preferred to use. It is better to use $timeout
The $timeout does not generate error like „$digest already in
progress“ because $timeout tells Angular that after the current cycle,
there is a timeout waiting and this way it ensures that there will not
any collisions between digest cycles and thus output of $timeout will
execute on a new $digest cycle
From what I understand it only runs once before the page is rendered. But is there ever a case where it runs after the page has been rendered?
I tried testing a few things with this plnkr:
angular
.module('app', [])
.directive('test', function($http) {
return {
restrict: 'E',
template: '<input />',
link: function(scope, el, attrs) {
var input = angular.element(el[0].children[0]);
input.on('change', function() {
console.log('change event');
scope.$apply(function() {
console.log('digest cycle');
});
});
input.on('keyup', function() {
console.log('keyup event');
var root = 'http://jsonplaceholder.typicode.com';
$http.get(root+'/users')
.success(function() {
console.log('http request successful');
})
.error(function() {
console.log('http request error');
});
});
console.log('link function run');
}
};
});
Does typing in the input field cause the link function to run?
Do event listeners cause the link function to run?
Do http requests (made with $http?) cause the link function to run?
Do digest cycles cause the link function to run?
The answer to all of these questions seem to be "no".
The link function runs when an instance of the directive is compiled, in this case, when a <test></test> element is created. That can be when angular's bootstrapping compiles the page, when it comes into being from a ng-if, when a ng-repeat makes it, when it's made with $compile, etc.
link will never fire twice for the same instance of the directive. Notably, it fires right after the template has been compiled in the directive's lifecycle.
1 - No, it causes to change the only ng-model if you have it binded.
2 - No, it will only launch the code inside the event binds.
3 - Again no, the event bind will launch the $http.get(). And please don't put an $http directly on your directive. Use a factory or something like that.
4 - Dunno
As Dylan Watt said, the directive link runs only when the directive is compiled (only once) per element/attr.... You can compile it in different ways. Plain http, $compile, ng-repeat....
You can create a $watch inside your directive to "relaunch" some code on a binded element change.
This maybe can help you: How to call a method defined in an AngularJS directive?
I have a webpage written in angular with an ngCloak directive. It is loaded in a dynamically sized iframe with pym.js.
The trouble is that the page does not appear unless I resize the browser or trigger a resize event, or call pymChild.sendHeight() after the page loads.
I don't see any events associated with ngCloak though. Is there an angular event for "page is rendered, controllers are initialized"?
There is the $timeout service:
$timeout(function() {
// this code will execute after the render phase
});
You could write a directive that execute a callback in postLink function, since the postLink will be called last in the $compile life cycle.
.directive('onInitialized', function ($parse) {
return {
restrict: 'A',
priority: 1000, // to ensure that the postLink run last.
link: function postLink(scope, element, attrs) {
$parse(attrs.onInitialized)(scope);
}
}
});
and place it at the element that you would like to know when it and all its template-ready decendants have got compiled, for example:
<body ng-controller="MainCtrl" on-initialized="hello()">
and in the MainCtrl controller:
app.controller('MainCtrl', function($scope) {
$scope.name = 'World';
$scope.hello = function () {
console.log('Hello ' + $scope.name);
};
})
For template-ready, I mean all directives except: directives with templateUrl and the template haven't ready in the $templateCache yet, since they will get compiled asynchronously.
Hope this helps.
Angular's ng-model is not updating when using jquery-ui spinner.
Here is the jsfiddle http://jsfiddle.net/gCzg7/1/
<div ng-app>
<div ng-controller="SpinnerCtrl">
<input type="text" id="spinner" ng-model="spinner"/><br/>
Value: {{spinner}}
</div>
</div>
<script>
$('#spinner').spinner({});
</script>
If you update the text box by typing it works fine (you can see the text change). But if you use the up or down arrows the model does not change.
Late answer, but... there's a very simple and clean "Angular way" to make sure that the spinner's spin events handle the update against ngModel without resorting to $apply (and especially without resorting to $parse or an emulation thereof).
All you need to do is define a very small directive with two traits:
The directive is placed as an attribute on the input element you want to turn into a spinner; and
The directive configures the spinner such that the spin event listener calls the ngModel controller's $setViewValue method with the spin event value.
Here's the directive in all its clear, tiny glory:
function jqSpinner() {
return {
restrict: 'A',
require: 'ngModel',
link: function (scope, element, attrs, c) {
element.spinner({
spin: function (event, ui) {
c.$setViewValue(ui.value);
}
});
}
};
};
Note that $setViewValue is intended for exactly this situation:
This method should be called when an input directive wants to change
the view value; typically, this is done from within a DOM event
handler.
Here's a link to a working demo.
If the demo link provided above dies for some reason, here's the full example script:
(function () {
'use strict';
angular.module('ExampleApp', [])
.controller('ExampleController', ExampleController)
.directive('jqSpinner', jqSpinner);
function ExampleController() {
var c = this;
c.exampleValue = 123;
};
function jqSpinner() {
return {
restrict: 'A',
require: 'ngModel',
link: function (scope, element, attrs, c) {
element.spinner({
spin: function (event, ui) {
c.$setViewValue(ui.value);
}
});
}
};
};
})();
And the minimal example template:
<div ng-app="ExampleApp" ng-controller="ExampleController as c">
<input jq-spinner ng-model="c.exampleValue" />
<p>{{c.exampleValue}}</p>
</div>
Your fiddle is showing something else.
Besides this: Angular can not know about any changes that occur from outside its scope without being aknowledged.
If you change a variable of the angular-scope from OUTSIDE angular, you need to call the apply()-Method to make Angular recognize those changes. Despite that implementing a spinner can be easily achieved with angular itself, in your case you must:
1. Move the spinner inside the SpinnerCtrl
2. Add the following to the SpinnerCtrl:
$('#spinner').spinner({
change: function( event, ui ) {
$scope.apply();
}
}
If you really need or want the jQuery-Plugin, then its probably best to not even have it in the controller itself, but put it inside a directive, since all DOM-Manipulation is ment to happen within directives in angular. But this is something that the AngularJS-Tutorials will also tell you.
Charminbear is right about needing $scope.$apply(). Their were several problems with this approach however. The 'change' event only fires when the spinner's focus is removed. So you have to click the spinner then click somewhere else. The 'spin' event is fired on each click. In addition, the model needs to be updated before $scope.$apply() is called.
Here is a working jsfiddle http://jsfiddle.net/3PVdE/
$timeout(function () {
$('#spinner').spinner({
spin: function (event, ui) {
var mdlAttr = $(this).attr('ng-model').split(".");
if (mdlAttr.length > 1) {
var objAttr = mdlAttr[mdlAttr.length - 1];
var s = $scope[mdlAttr[0]];
for (var i = 0; i < mdlAttr.length - 2; i++) {
s = s[mdlAttr[i]];
}
s[objAttr] = ui.value;
} else {
$scope[mdlAttr[0]] = ui.value;
}
$scope.$apply();
}
}, 0);
});
Here's a similar question and approach https://stackoverflow.com/a/12167566/584761
as #Charminbear said angular is not aware of the change.
However the problem is not angular is not aware of a change to the model rather that it is not aware to the change of the input.
here is a directive that fixes that:
directives.directive('numeric', function() {
return function(scope, element, attrs) {
$(element).spinner({
change: function(event, ui) {
$(element).change();
}
});
};
});
by running $(element).change() you inform angular that the input has changed and then angular updates the model and rebinds.
note change runs on blur of the input this might not be what you want.
I know I'm late to the party, but I do it by updating the model with the ui.value in the spin event. Here's the updated fiddle.
function SpinnerCtrl($scope, $timeout) {
$timeout(function () {
$('#spinner').spinner({
spin: function (event, ui) {
$scope.spinner = ui.value;
$scope.$apply();
}
}, 0);
});
}
If this method is "wrong", any suggestions would be appreciated.
Here is a solution that updates the model like coder’s solution, but it uses $parse instead of parsing the ng-model parameter itself.
app.directive('spinner', function($parse) {
return function(scope, element, attrs) {
$(element).spinner({
spin: function(event, ui) {
setTimeout(function() {
scope.$apply(function() {
scope._spinnerVal = = element.val();
$parse(attrs.ngModel + "=_spinnerVal")(scope);
delete scope._spinnerVal;
});
}, 0);
}
});
};
});