I was wondering how to change the data, but keep the same controller in my angular app. Basically I will have a list of activities (restaurants, parks etc...) when I click on one of these activities, The view will display all the restaurant, and same thing for the parks. I know how to do that, but I would need to create a park_ctrl and a restaurant_ctrl, and since the data will be formatted the exact same way. I just wanted to know if I could use only one controller and just change the data that it receives when I click on those buttons.
I hope my question makes sense.
logic around retrieving data should be the responsibility of services, so I guess you'd just call a different service in the different cases, from the same controller
I think it's not a really good idea, but opinion based.
You can make a function :
function($scope){
$scope.changePage = function (type) {
if(type==="park"){
$scope.parks = asynLoadFunctionToGetParks();
}else{
if(type === "restaurants"){
/* same as below */
}
}
};
}
And changing the type in your view with :
<button ng-click="changePage('parks')">Parks</button>
<button ng-click="changePage('restaurants')">Restaurants</button>
<div ng-if="type==='park'">
{{parks}}
</div>
<div ng-if="type==='restaurants'">
{{restaurants}}
</div>
I think the issue here is that most of the Angular examples available are of the "hello world" variety and so they show retrieving data directly from the Controller. The problem is that AngularJS out of the box doesn't really have a business logic layer itself, and I think most people who have added such a layer are too busy to be putting up examples.
The way I'd do this is to create a "master" service that can get all of the different data types either up front in the Run block or lazily as the user navigates the app, depending on your needs. Then I'd supply a reference to the applicable sub-collection in the route resolution (resolve property) or the isolate scope in the case of a directive.
Alternatively, the controller can ask for the data by calling masterService.getCollection($scope.collectionName) or something like that, but if you do that you run into the issue that masterService may not yet have that particular collection yet and then you have to clutter up your controller with all the promise resolution stuff as if it were a Controller's responsibility to handle that.
You could avoid that by binding to masterService.collections[$scope.collectionName] in the View, which would leave the Controller only exposing the collection on the $scope or controllerAs variable and the masterService still responsible for retrieving the data and making it available.
Yes you can. Just use different service and a common variable in the scope.
if (something) {
$scope.data = restaurantsService.get();
} else {
$scope.data = parksService.get();
}
Related
While transitioning an existing angular site, I encountered an annoying problem. The initial symptom was that a certain controller was not running it's initialize function immediately following the login. I logged and I tracked, and eventually I realized it was a design flaw of the page. Essentially, index.html contains a <header>, <ng-view>, and <footer>. There are a couple of ng-if attributes that live in the header that I want to evaluate after the login, but since the view is the only thing that is reloaded, it was not reinitializing the header controller, and thus not updating the ng-if values.
Then I was reminded of ngInclude, which seems like the perfect solution, until I got it hooked up and realize that doesn't work either. It loads the template the first time, and doesn't reinitialize when the view changes. So then I got the bright idea of passing the HeaderController to another controller or service, and controlling this one stubborn boolean value through a proxy of sorts. That also didn't work. Then I tried putting a function and a boolean into another service, and mirroring that property in the header controller, but thus far I have not gotten this working.
I have done plenty of research about multiple views in the index, and so far I hear a lot about this ui-router, but I'm still not convinced that is the way I want to go. It does not seem to be a simple solution. I have not tried putting the ng-include into the templates yet either, because then I feel like that is going back in time to when we had to update 100 pages every time we changed the menu.
I lost a whole day to this. If anyone could tell me how to trigger the evaluation of this one property in my header controller which I would like to live outside the other templates, please let me know!
Ok so you need to know in your HeaderController when the view has reloaded. There's a number of ways of doing this but the easier and maybe the more correct in this particular case is with an event.
So when you are refreshing the view you just do this, let's say you need the new value of ob1 and ob2 variables.
// ViewController
$rootScope.$emit('viewRefresh', {ob1: 'newvalue1', ob2: 'newvalue2'});
And in your HeaderController you need to listen for that event, and set on your $scope the new values for those attrs (if you're not using controller as syntax).
// HeaderController
$rootScope.$on('viewRefresh', function onRefresh(event, data) {
$scope.ob1 = data.ob1;
$scope.ob2 = data.ob2;
})
Another Solution
Sharing a Promise through a Service (using $q)
function HeaderService($q) {
var defer = $q.defer();
return {
getPromise: function() {return defer.promise},
notify: function(data) {defer.notify(data)}
}
}
function HeaderController(HeaderService) {
var vm = this;
HeaderService.getPromise().then(function(data) {
vm.ob1 = data.ob1;
vm.ob2 = data.ob2;
})
}
function ViewController(HeaderService) {
var data = {ob1: 'newvalue1', ob2: 'newvalue2'};
HeaderService.notify(data)
}
In a view I have a link to choose a start location like below:
<input type="text" ng-model="placeStart" placeholder="place to start">
<input type="text" ng-model="weight" placeholder="goods weight">
and in the location page, I do choose a place, however, When I use $ionicHistory.goBack(), I could not pass the "place" back to the previous view. I also do not want to use state.go('previous view') to pass the "place", because in that way, I will lost the other input information in the previous view.
Here is :
$ionicHistory.backView().stateId;
don't ignore to include $ionicHistory on controller
There are three options which immediately come to mind. $rootScope, localStorage and using routing not goBack().
If you need the value from one view in another, and they're completely separate controllers etc then you need a way to pass them around.
You could create and then put the value into $rootScope.globals or similar.
You could store the value to localStorage before sending the user back.
You could redirect correctly to a route which allows the values to be included in the url and still show the provious page. For example the same route with and without values set, using - or 0 for not set depending on data type:
/an/example/route/-/-/
/an/example/route/0/0/
/an/example/route/123/456
Update:
There is actually a fourth way where you can send data between controllers using $broadcast and $on. The broadcast happens in the sending controller and the $on listens in the receiving controller(s) so you can send an update to values / an object etc. $on and $broadcast in angular
It depends on your situation but if you don't care to preserve state after a page reload which localStorage would be good for, but rather have the state be remembered just when you're going back (and not necessarily when you later navigate forward back into the view again) then I do this: I make a separate service, just an object that sticks around in which I can inject anywhere and store some variables. In Angular 1 this would be a service object.
angular.module('foo').factory("placeHelper", [
() => {
let _place = null;
class PlaceHelper {
set place(place){
_place = place;
}
get place(){
return _place;
}
reset(){
_place = null;
}
}
let helper = new PlaceHelper();
return helper;
}
]);
Then in your controller that you're going back to, you inject placeHelper and ask it for the place and restore your state via $scope.place = placeHelper.place and when in the UI for that controller someone selects a place, you just store it in the service, placeHelper.place = $scope.place.
I would use localStorage within the service if I wanted to keep the state around after a page refresh.
I don't like polluting $rootScope because it's harder to keep track after you start to have more than a few unrelated methods in there and your properties need to have longer names (or get grouped in objects anyway). It's better for maintainability to encapsulate and separate concerns.
Service variation:
The service could be an object literal instead of a class and you could directly set the properties instead of using methods if you wanted it to be a bit more simple.
angular.module('foo').factory("placeHelper", [
() => {
let helper = {
place: null,
reset(){
this.place = null;
}
};
return helper;
}
]);
I stumbled on the same problem recently. I ended up deciding to use $ionicHistory.currentView() and $ionicHistory.backView() (see documentation here). The former function returns an object associated to the current view, while the latter returns an object associated to the view you will go to after you call $ionicHistory.goBack().
Before calling $ionicHistory.goBack() on your location page you call $ionicHistory.backView() and define a new property to the returned object whose contents is the data you want to propagate to the other view.
On your other view, you change its '$ionicView.enter' event handler so it calls $ionicHistory.currentView(), which retrieves the object with the data you want.
If I understand correctly, a controller is generated when its view becomes active?
Meaning that if the view is not visible, the controller doesn't exist/isn't active?
Is there any way that I can make the controller active "in the background"?
I have an app which has two main tabs, one for vehicle tracking & the other for something else. Each of those tabs has several sub-tabs (suing UI-Router); in the case of the vehicle tracking, I have one tab for a google map & another to show a grid with street addresses.
Here's a pic of the desktop app which I am trying to re-implement in Angular:
Now, I am an Angular beginner, so maybe my design idea is flawed, but:
Both the map and the vehicle locations tab use the identical data pulled from a server, which is a list of GPS lat/long & timestamp.
It seemed to me that it would be wrong to have each of those tabs (controllers) fetching the same data, duplicating code.
So, I wanted to have a controller for the "Vehicle locations" tab, which would get the data and feed it to a service which the two map/Vehicle locations sub-tabs (controllers) could $watch.
Even if I were not looking at that "parent view" ("Vehicle locations", but at another ("Vehicle reports" or "Employee reports"), I would this data downloading & view updating to continue, so that when the user clicks the "Vehicle locations" tab, the information is already there & the user doesn't have to wait while the app goes to the server to fetch data & draw its view.
Question: can Angular work that way, or am I asking it to do something which is un-angular-ish? If so, what is the correct way to implement this? Should I duplicate the $http.get code and should I have the controllers fetching & updating their own data on $scope.$on('$viewContentLoaded'?
If you need a central point of access for data in your AngularJS app, the best way to achieve it is to encapsulate it in a provider (either a service or a factory). Fetch the data in your provider and implement getters, so that you can inject it in your controllers and ask for the data without duplicating code and requests.
yourApp.service('serviceName', [ '$http',
function($http) {
this.getData = function() {
return $http.get(...);
}
}
]);
yourApp.controller('controllerA', ['serviceName',
function(serviceName) {
serviceName.getData().then(function(data){
$scope.data = data;
});
}
]);
//the same for other controllers
There are some points you can consider for this app:
You can create a factory for data you intend to share and reuse. So maybe create a http factory to get the data from the server and then inject it to whichever controllers you need to. Also you can resolve incoming data with "resolved" in angularjs (an option in routes) to make sure it's available before the page renders.
If you are passing in data within controller to http.get then, inject the factory and use promises with the http method.
I am working on a SPA that pulls in customer data from one $resource call, and gets some generic preference data from another $resource call.
The preference data is sent as an array, which I want to use to populate a series of checkboxes, like so:
<div ng-repeat="pref in fieldMappings.mealPrefs">
<input type="checkbox"
id="pref_{{$index}}"
ng-model="customer.mealPrefs"
ng-true-value="{{pref.name}}" />
<label class="checkbox-label">{{pref.name}}</label>
</div>
When a user clicks one or more checkboxes, I want the values represented in that array of checkboxes to be mapped to an array nested inside a customer object, like so:
.controller( 'AppCtrl', function ( $scope, titleService, AccountDataService ) {
// this is actually loaded via $resource call in real app
$scope.customer = {
"name": "Bob",
"mealPrefs":["1", "3"]
};
// this is actually loaded via $resource call in real app
$scope.fieldMappings.mealPrefs = [
{'id':"1", 'name':"Meat"},
{'id':"2", 'name':"Veggies"},
{'id':"3", 'name':"Fruit"},
{'id':"4", 'name':"None"}
];
});
I have tried setting up ng-click events to kick off functions in the controller to manually handle the logic of filling the correct part of the customer object model, and $watches to do the same. While I have had some success there, I have around 2 dozen different checkbox groups that need to be handled somehow (the actual SPA is huge), and I would love to implement this functionality in a way that is very clean and repeatable, without duplicating lots of click handlers and setting up lots of $watches on temporary arrays of values. Anyone in the community already solved this in a way that they feel is pretty 'best practice'?
I apologize if this is a repeat - I've looked at about a dozen or more SO answers around angular checkboxes, and have not found one that is pulling values from one object model, and stuffing them in another. Any help would be appreciated.
On a side-note, I'm very new to plunkr (http://plnkr.co/edit/xDjkY3i0pI010Em0Fi1L?p=preview) - I tried setting up an example to make it easier for folks answer my question, but can't get that working. If anyone wants to weigh in on that, I'll set up a second question and I'll accept that answer as well! :)
Here is a JSFiddle I put together that shows what you want to do. http://jsfiddle.net/zargyle/t7kr8/
It uses a directive, and a copy of the object to display if changes were made.
I would use a directive for the checkbox. You can set the customer.mealPrefs from the directive. In the checkbox directive's link function, bind to the "change" event and call a function that iterates over the customer's mealPrefs array and either adds or removes the id of the checkbox that is being changed.
I took your code and wrote this example: http://plnkr.co/edit/nV4fQq?p=preview
I'm stating to learn AngularJS, coming from a lot of different MV* frameworks.
I like the framework, however I'm having trouble with passing data between Controllers.
Suppose I have a screen with some input (input.html) and a controller, let's say InputCtrl.
There's a button on this view which takes you to another screen, let's say approve (approve.html) with a controller ApproveCtrl.
This ApproveCtrl needs data from the InputCtrl. This seems like a very common scenario in bigger applications.
In my previous MV* frameworks, this would be handled like (pseudo-code):
var self = this;
onClick = function() {
var approveCtrl = DI.resolve(ApproveCtrl);
approveCtrl.property1 = self.property1;
approveCtrl.property1 = self.property2;
self.router.show(approveCtrl);
}
It would work like Controller- first.
You create the controller first, having a chance to put it in the right state; afterwards the View gets created.
Now, in AngularJS, I'm handling this like:
var self = this;
onClick = function(){
self.$locationService.path('approve');
}
This works like View-first.
You say to which view / route to navigate, the Controller gets created by the framework.
I find it hard to control the state of the created Controller and pass data to it.
I've seen and tried following approaches, but all have it's own issues in my opinion:
Inject a shared service into InputCtrl & ApproveCtrl and put all data to be shared on this service
This looks like a dirty work-around; the state in the shared service becomes global state, while I just need it to pass data to the ApproveCtrl
The lifetime of this shared service is way longer than what I need it for - just to pass data to the ApproveCtrl
Pass the data in $routeParams
This gets quite messy when having the pass a lot of parameters
Use $scope events
Conceptually, this is not something I would use events for - I just need to pass data to the ApproveCtrl, nothing event-ish
This is quite cumbersome; I have to send an event to the parent first, that would then broadcast it to it's children
Am I missing something here? Am I creating too many small Controllers?
Am I trying to hold on to habits from other frameworks too much here?
In terms of structure AngularJS is more Modular than MVC one.
Classic MVC describes 3 simple layers which interact with each other in such way that Controller stitches Model with View (and Model shouldn't rather work with View directly or vice versa).
In Angular you can have multiple, some completely optional, entities which can interact between each other in multiple ways, for example:
That's why there are multiple ways of communicating your data between different entities. You can:
Send messages directly between controllers using difference between this and $scope
Send messages using events
Send messages using shared system (Note: same link as above, answer shows both techniques)
or
Send messages using AJAX backend
Send messages using external system (such as MQ)
...and a lot more. Due to its diversity Angular allows developer/designer to choose way they are most comfortable with and carry on. I recommend reading AngularJS Developer Guide where you can find blessed solutions to some common problems.
If your intent is to simply share data between two views, a service is probably the way to go. If you are interested in persisting to a data store, you may want to consider some sort of back-end service such as a REST API. Take a look at the $http service for this.
Even if XLII gave a complete response, I found this tutorial using a service. It's very interesting and a simple way for sharing data between controlers using the 2 ways binding property : https://egghead.io/lessons/angularjs-sharing-data-between-controllers
I still havn't used it for now.
Otherwise there is also this other way, based on events : http://www.objectpartners.com/2013/08/21/using-services-and-messages-to-share-data-between-controllers-in-angularjs/
If you wish to pass simple string data from one page (page1) to another page (page2), one solution is to use traditional url parameters. Invoke the page2 route url with parameter like "/page2/param1/param2". The controller of page2 will receive the parameters in "routeParams". You will be able to access parameteres as routeParams.param1 and routeParams.param2. The code below is adopted from: How to get the url parameters using angular js
Invoke the page2 route from page1's controller(js) or a url in its html with parameters as:
"/page2/param1/param2"
Page2 route:
$routeProvider.when('/page2/:param1/:param2', {
templateUrl: 'pages/page2.html',
controller: 'Page2Ctrl'
});
And the controller:
.controller('Page2Ctrl', ['$scope','$routeParams', function($scope, $routeParams) {
$scope.param1 = $routeParams.param1;
$scope.param2 = $routeParams.param2;
...
}]);
Now you can access the parameters (param1 and param2) values in your page2's html/template as well.