I have a directive and it works fine in a way such that when I type something the search() scope function inside my directive fires and sets $scope.query with the input text.
here is the directive template
<div class="container">
<div class="system-filter-header">
<div class="no-gutter">
<div class="system-search-wrapper search-wrapper-width">
<i ng-click="search($evt)" class="fa fa-search"></i>
<input type="text" ng-keyup=search($evt) class="search pull-left suggesstions-styles"
ng-model="query" ng-attr-placeholder="Search...">
</div>
</div>
</div>
</div>
here is the scope function which gets triggered
$scope.search = function() {
console.log($scope.query.length)
}
But when I used an ng-if="true" in first line of template (true used for generalizing only, I want to do a different conditional check inside ng-if) such that,
<div class="container" ng-if="true">
still the search gets triggered but the console.log gives always 0 and it doesn't seem to update the $scope.query value as it stays as $scope.query = ''
throughout the typing.
EDIT
Here is a an example codepen with almost similar behaviour. The problem is with the searchBox directive and I have added ng-if=true to the template but searching doesn't work. When I remove the ng-if searching works fine.
Any reason for this?
Rule of thumb in AngularJS: your ng-model should always include a dot. Otherwise AngularJS directives that create child scopes (like ng-if or ng-repeat) will create a duplicate property on that child scope instead of the parent scope. Following the controllerAs convention completely mitigates this behavior.
Related
I have a label with an input box like so:
<label class="item item-input">
<input type="text" data-ng-model="description"
placeholder="Add a Description!">
</label>
As you can see this input box is binded to the scope "description"
In my controller I have something along the lines of this:
$scope.description = "";
$scope.submit = function() {
console.log($scope.description);
};
In my HTML I also have this line:
<div ng-show="description.length <= maxChars">{{description}}</div>
The submit function is called when the user hits the submit button after typing inside the input box. The description displays correctly. As the user types into the input box the description gets updated in the HTML but NOT in the controller.
I have a feeling it has something to do with setting description to an empty string but it is clearly getting updated as far as the HTML is concerned. But it keeps console.logging and empty string regardless.
In order to get this to work I had to pass description directly into the submit function (And also update the function accordingly):
<button class="button button-positive" data-ng-click="submit(description)">Submit</button>
This is completely unnecessary since Angular should be doing Two-way data binding automatically but it's not.
Anyone have any ideas?
Any help would be appreciated.
EDIT:
Here is the full HTML due to popular demand.
<ion-view title="Moments" id="page2">
<ion-content padding="true" class="has-header">
<img src="{{picture}}" height="300px" width="100%"> </img>
<div class="row">
<div ng-show="description.length > maxChars" style= "color: red">{{description}}</div>
<div ng-show="description.length <= maxChars">{{description}}</div>
</div>
<div class="row" ng-if="description">
<div ng-show="description.length > maxChars" style= "color: red">{{description.length}} / {{maxChars}}</div>
<div ng-show="description.length <= maxChars" style= "color: green">{{description.length}} / {{maxChars}}</div>
</div>
<div class="row">
<div class="col">
<label class="item item-input">
<input type="text" data-ng-model="description" placeholder="Add a Description!">
</label>
</div>
<button style="margin-right: 5px" class="col col-10 button button-positive" data-ng-click="checkDescription(description)">OK</button>
</div>
<div class="row">
<div class="col"><ion-checkbox data-ng-change="changeLocation()" data-ng-model="location">Show Location</ion-checkbox></div>
</div>
<div class="row">
<div class="button-bar">
<button class="button button-assertive" data-ng-click="cancel()">Cancel</button>
<button class="button button-positive" data-ng-click="submit(description)">Submit</button>
</div>
</div>
</ion-content>
</ion-view>
I am also aware that in this question the submit function takes no parameters. That's how I would like it to be. Currently my submit button takes one parameter(the description). This should not be nessesary. I am having the same problem with the function 'checkDescription' as well. That function should also have no parameters but again, I am forced to pass the description directly into the function. Something I prefer not to do.
Executive Summary:
In AngularJS, a child scope normally prototypically inherits from its parent scope. One exception to this rule is a directive that uses scope: { ... } -- this creates an "isolate" scope that does not prototypically inherit.（and directive with transclusion） This construct is often used when creating a "reusable component" directive. In directives, the parent scope is used directly by default, which means that whatever you change in your directive that comes from the parent scope will also change in the parent scope. If you set scope:true (instead of scope: { ... }), then prototypical inheritance will be used for that directive.
Scope inheritance is normally straightforward, and you often don't even need to know it is happening... until you try 2-way data binding (i.e., form elements, ng-model) to a primitive (e.g., number, string, boolean) defined on the parent scope from inside the child scope. It doesn't work the way most people expect it should work. What happens is that the child scope gets its own property that hides/shadows the parent property of the same name. This is not something AngularJS is doing – this is how JavaScript prototypal inheritance works. New AngularJS developers often do not realize that ng-repeat, ng-switch, ng-view, ng-include and ng-if all create new child scopes, so the problem often shows up when these directives are involved. (See this example for a quick illustration of the problem.)
This issue with primitives can be easily avoided by following the "best practice" of always have a dot '.' in your ng-models – watch 3 minutes worth. Misko demonstrates the primitive binding issue with ng-switch.
--AngularJS Wiki -- The Nuances of Scope Prototypal Inheritance
I tried to do the '.' notation in my scope but whenever I try to reference it like this:
$scope.moment.description = "";
It says "Cannot read property 'description' of undefined.
The code needs to create the object before assigning a value to a property:
$scope.moment = {};
$scope.moment.description = "";
//OR
$scope.moment = { description: "" };
ng-show is not working in following code
<button ng-click="itemIndex=0;showHome=true;" class="btn btn-link">Home</button>
<div ng-if="itemIndex==0">
<div ng-show="showHome">{{showHome}}
<h3>Home Section</h3>
<img ng-click="showHomeItems=showHomeItems?false:true;showHome=false;" ng-src="images/home.png"/>
</div>
<div ng-show="showHomeItems">
Home Items{{showHome}}
</div>
</div>
Without ng-if it is working fine but with ng-if its not working.
Read this article.
There are some directives in Angular that create a child scope, like ng-repeat, ng-if.
Inside those scopes, the booleans (such as showHome) are searched only within that new scope, and not in the parent scope.
In order to avoid such bugs, it's considered best practice to place the logic in the controller (or service, just not in the HTML) inside an object, which is not a primitive variable and will be looked up in the scope prototypical chain.
Try declaring a variable like this:
$scope.switch = {showHome : true}
and then use it in the html like this:
<div ng-show = "switch.showHome" >
This is weird as it should be pretty straightforward. I will post my code first and then ask the question:
html -
<div ng-controller="myController" ng-switch on="addressCards">
<div>
{{addCustom}} // does not get changed
<div ng-if="addCustom === false">
{{addCustom}} // does get changed
<button type="button" class="btn btn-primary btn-icon-text" ng-click="addCustom = true">
<span class="icon icon-plus"></span>
click here
</button>
</div>
</div>
</div>
controller -
(function(){
'use strict';
angular.module('myApp')
.controller('myController',['$scope',myController]);
function myController($scope){
$scope.addCustom = false;
}
})();
So I simply introduced a scope variable - addCustom - in my controller and set it to false as default. This variable controls if a div is shown or not. I am also outputting the value of the scope on the html at 2 different locations. Please see above.
But when I change its value in an ng-click within this divs, its value is changing at the second location(within the div) but not the first one(outside the div). Because of this the div does not change state as well.
I am not able to figure what might be possibly wrong here. Can someone please help?
The thing happening is when you have ng-repeat,ng-switch and ng-if directive, angular creates child scope for those element wherever they are placed. Those newly created scope are prototypically inherited from there parent scope.
On contrast Prototypal Inheritance means?
If you have scope hierarchy, then parent scope property are accessible inside child scope, only if those property are object (originally object referenced is passed to child scope without creating its new reference). But primitive datatypes are not accessible inside child scope and if you looked at your code addCustom scope variable is of primitive dataType.
Lets discuss more about it.
Here you have myController controller which has addCustom scope variable of primitive type & as I said above ng-switch & ng-if directive are compiled they do create new child scope on that element. So in your current markup you have ng-switch on ng-controller="myController" div itself. For inner html it had created a child scope. If you wanted to access parent scope inside child(primitive type) you could use $parent notation before scope variable name. Now you can access the addCustom value by $parent.addCustom.
Here its not over when angular compiler comes to ng-if div, it does create new child scope again. Now inner container of ng-if will again have child scope which is prototypically inherited from parent. Unfortunately in your case you had primitive dataType variable so you need to use $parent notation again. So inside ng-if div you could access addCustom by doing $parent.$parent.addCustom. This $parent thing will solve your problem, but having it on HTML will make unreadable and tightly couple to its parent scope(suppose on UI you would have 5 child scope then it will look so horrible like $parent.$parent.$parent.$parent). So rather you should go for below approach.
Follow Dot rule while defining ng-model
So I'd say that you need to create some object like $scope.model = {} and add addCustom property to it. So that it will follow the prototypal inheritance principle and child scope will use same object which have been created by parent.
angular.module('myApp')
.controller('myController',['$scope',myController]);
function myController($scope){
$scope.model = { addCustom : false };
}
And on HTML you will use model.addCustom instead of addCustom
Markup
<div ng-controller="myController" ng-switch on="addressCards">
<div>
{{model.addCustom}} // does not get changed
<div ng-if="model.addCustom === false">
{{model.addCustom}} // does get changed
<button type="button" class="btn btn-primary btn-icon-text" ng-click="model.addCustom = true">
<span class="icon icon-plus"></span>
click here
</button>
</div>
</div>
</div>
Other best way to deal with such kind of issue is, use controllerAs pattern while using controller on HTML.
Markup
<div ng-controller="myController as myCtrl" ng-switch on="addressCards">
<div>
{{myCtrl.addCustom}} // does not get changed
<div ng-if="myCtrl.addCustom === false">
{{myCtrl.addCustom}} // does get changed
<button type="button" class="btn btn-primary btn-icon-text" ng-click="myCtrl.addCustom = true">
<span class="icon icon-plus"></span>
click here
</button>
</div>
</div>
</div>
From the Docs:
The scope created within ngIf inherits from its parent scope using prototypal inheritance. An important implication of this is if ngModel is used within ngIf to bind to a javascript primitive defined in the parent scope. In this case any modifications made to the variable within the child scope will override (hide) the value in the parent scope.
-- AngularJS ng-if directive API Reference
The rule of thumb is don't bind to a primitive, instead bind to an object.
Scope inheritance is normally straightforward, and you often don't even need to know it is happening... until you try 2-way data binding (i.e., form elements, ng-model) to a primitive (e.g., number, string, boolean) defined on the parent scope from inside the child scope. It doesn't work the way most people expect it should work. What happens is that the child scope gets its own property that hides/shadows the parent property of the same name. This is not something AngularJS is doing – this is how JavaScript prototypal inheritance works. New AngularJS developers often do not realize that ng-repeat, ng-if, ng-switch, ng-view and ng-include all create new child scopes, so the problem often shows up when these directives are involved. (See this example for a quick illustration of the problem.)1
This issue with primitives can be easily avoided by following the "best practice" of always have a '.' in your ng-models – watch 3 minutes worth. Misko demonstrates the primitive binding issue with ng-switch.1
Ng-if introduces a different scope. Try this as an attribute of your button:
ng-click="$parent.addCustom = false"
This will assure that you're accessing the same scope.
It's because of this that it's always good practice to use the ControllerAs syntax. All attributes are bound to the controller object and namespaced accordingly, meaning you never run in to this problem. I've updated your example using the ControllerAs syntax to demonstrate its use.
HTML
<div ng-controller="myController as vm" ng-switch on="addressCards">
<div>
{{vm.addCustom}}
<div ng-if="vm.addCustom === false">
{{vm.addCustom}}
<button type="button" class="btn btn-primary btn-icon-text" ng-click="vm.addCustom = true">
<span class="icon icon-plus"></span>
click here
</button>
</div>
</div>
</div>
Controller
(function(){
'use strict';
angular.module('myApp')
.controller('myController', [ myController ]);
function myController () {
var vm = this;
vm.addCustom = false;
}
})();
Here is an excellent article providing more detail about ControllerAs and it's advantages.
Both Classic Controller and Controller As have $scope. That's super important to understand. You are not giving up any goodness with either approach. Really. Both have their uses.
I am inexperienced with angular.
I am using angular to create a series of nested divs (a form) on a webpage. The top div has ng-controller="controllername" as an attribute. Within the nested divs is a div with ng-show="showvar" as an attribute.
It looks like this.
<div class="page">
<div ng-controller="controllername">
<div ng-show="showvar">Hidden Stuff</div>
</div>
</div>
When I perform functions on showvar to make it true, the div appears (and disappears when false) as intended.
I also have a completely separate div 'outside' the the original nest of divs with the ng-controller attribute. As such, there is no ng-controller attribute in this seperate hierarchy BUT I have nested another div inside with the ng-show="showvar" attribute.
Updated HTML structure is as such
<div class="page">
<div ng-controller="controllername">
<div ng-show="showvar">Hidden Stuff</div>
</div>
<div class="seperate">
<div ng-show="showvar">More Hidden Stuff</div>
</div>
</div>
When the page loads, both divs with ng-show="showvar" in the separate nests are hidden as ng-hide has been appended by angular. When I perform functions on showvar after the page load to make it true, only the div within the ng-controller div gets shown.
I (think I) understand this is because the ng elements are evaluated at page load (and appended with ng-hide, even outside the controller?) but only the ng elements within the div with the ng-controller attribute are evaluated when functions are performed after page load. Is this correct?
How can I get the other ng-show to be evaluate 'outside' of the ng-controller div?
I was thinking one option is to append ng-controller to the overall 'page' div instead of the nested div. But what other options do I have?
EDIT: I also tried simply adding ng-controller="controllername" to the separate div. I guess angular 'ignores' the duplicate ng-controller div?
The problem your facing is that the showvar resides in your controller's scope, your second usage of the showvar is not within that scope.
What you need to do is make sure the variable is available where needed.
Say you add the variable to the parentController (you don't have one in your example so I'll add one)
<div class="page" ng-controller="parentController">
<div ng-controller="controllername">
<div ng-show="showvar">Hidden Stuff</div>
</div>
<div class="seperate">
<div ng-show="showvar">More Hidden Stuff</div>
</div>
</div>
app.controller('ParentController', function($scope){
$scope.showvar = false;
});
problem with this is when you set showvar to true within your controllername controller it will set it in the innerscope and not the outer. When making sure you have the right scope by accessing it through another object you should be safe.
So try it like this:
<div class="page" ng-controller="parentController">
<div ng-controller="controllername">
<div ng-show="obj.showvar">Hidden Stuff</div>
</div>
<div class="seperate">
<div ng-show="obj.showvar">More Hidden Stuff</div>
</div>
</div>
app.controller('ParentController', function($scope){
$scope.obj = {
showvar: false
}
});
Quick demo
Your issue here is that you ended with 2 "showvar" variables: one within the "controllername" scope and another one on the app scope (as you have a ng-app declaration somewhere in your html parent of the "page" div).
When you load your page, you get the value of "showvar" in the controller scope for the first div, and for the "separate" one, you get the "showvar" variable in the app scope, which doesn't exist, therefore it is resolved to "false" (even though angular declares it for you in your app scope and you can even modify its value later).
When you change the value of "showvar" in the controller scope, it doesn't change the one in the app scope, making the "separate" div stay hidden forever =)
i try use ng-if, but angular no compile him. Look in test code:
<ul class="tmmenu-admin-tabs-builder-panel-answer">
<li class="tmmenu-admin-tabs-builder-panel-portlet" ng-repeat="answer in answers">
<div>
<span ng-repeat="question in questions">
<label ng-repeat="answer in question.answers">
<input type="checkbox">{{question.id}}.{{answer.id+1}}
<span ng-if="test()">ddd</span>
</label>
</span>
</div>
<textarea>{{answer.text}}</textarea>
</li>
</ul>
and function test:
$scope.test = function(){
console.log('d');
return false;
}
if run this page, we can see "ddd" in "Li" despite to test return false.
Next step, i replaced at "ng-if" "ng-show" :
<ul class="tmmenu-admin-tabs-builder-panel-answer">
...
<span ng-show="test()">ddd</span>
...
</ul>
And its working, "ddd" hide. Why ng-if not working where working ng-show?
The ngIf directive removes or recreates a portion of the DOM tree based on an {expression}. If the expression assigned to ngIf evaluates to a false value then the element is removed from the DOM, otherwise a clone of the element is reinserted into the DOM.
The ngShow directive shows or hides the given HTML element based on the expression provided to the ngShow attribute. The element is shown or hidden by removing or adding the ng-hide CSS class onto the element. The .ng-hide CSS class is predefined in AngularJS and sets the display style to none (using an !important flag). For CSP mode please add angular-csp.css to your html file (see ngCsp).
Could be a scope problem, is there something in a child scope that might override the value for test? ng-if works fine for me (plunker). I assume that everything else is working fine, are you seeing 'd' in the console to show that your function is getting executed?
Try changing your tag to this to help debug and you should see that it is a function:
<span ng-if="test()">test is: {{test.toString()}}</span>