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 $templateCache yet, since they will get compiled asynchronously.
Hope this helps.
Related
To start off, I know there are loads of similar questions but none that I found which supports execution of arbitrary methods with event listeners.
I have this directive which executes functions passed when the window resizes.
app.directive('onResize', function() {
var directive = {
'link': function(scope, element, attrs) {
var onResizeHandler = scope.$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 - $event.
I want to add a directive that will do something when an element class is changed.
My directive is:
(function (angular) {
angular.module('myApp')
.directive('myClassWatch', myClassWatch);
function myClassWatch() {
return {
restrict: 'A',
link: function (scope, element, attrs, controller) {
scope.$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');
});
}]);
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've got a pretty standard directive that lives on an anchor element, which parses a string to see whether the current route matches that link, e.g.
Dashboard
This directive runs each time the route changes (as the links can live outside of the ng-view which changes, so their state needs to be refreshed on a route change), using $routeChangeStart. This works fine within my main navigation, which lives within a standard view, but if I use this directive within an ng-included file (like my subnavigations), it fails to run any code inside the routeChangeStart callback. I've tried injecting $rootScope instead, but it makes no difference. The directive is as follows:
angular.module('myApp').directive('navItem', ['$rootScope','$location', function ($rootScope, $location) {
return {
restrict: 'A',
scope: false,
link: function postLink(scope, element, attrs) {
console.log('All directive elements execute this!');
$rootScope.$on('$routeChangeStart', function() {
console.log('ng-included elements work execute this!');
});
}
}
}]);
How can I get access to this event from inside a directive within an ng-include template? The directive runs, but just won't pick this up.
Thanks
I've been trying to recreate it on plunker but it works for me
http://plnkr.co/edit/9hbTLxGjoTNsM44zq6rw?p=preview
app.directive('navItem', ['$rootScope','$location', function ($rootScope, $location) {
return {
restrict: 'A',
scope: false,
link: function postLink(scope, element, attrs) {
console.log('All directive elements execute this!');
$rootScope.$on('$routeChangeStart', function() {
console.log('ng-included elements work execute this!');
});
}
}
}]);
check my plunker maybe you can find a difference between yours and mine code
app.controller("MainController", function($scope, $http){
$scope.items= [];
console.log('hi');
$http.get('../assets/data/data.json').then(function(response) {
$scope.drinks =response.data.drinks;
});
});
app.directive('cycle', function() {
return {
restrict: 'A',
link: function(scope, element, attrs) {
$(element).cycle({
fx: 'fade',
timeout: 10
});
}
};
});
I have the above AngularJS and when I run my page the Console.Log shows [cycle] terminating; too few slides: 0 and then it shows the Get Request after.
How would I be able to run the directive once the $http.get has finished?
try doing this
<div cycle ng-if="drinks"></div>
that way element that contains directive will be compiled in browser only when the drinks are available
There are two things you can use
ng-cloak
ng-show and ng-hide and custom scope property
Also consider using animation instead of creating manual animation within directive