Maintain the values in Angular Views - angularjs

I am new to Angular.js and i am facing problem in maintaining the JSON feed values in the view.
I am using different routers and when i launch the app it loads the home.html which in turns calls the homeCtrl and make an HTTP call and binds the data using ng-repeat ( in home.html ). If user clicks on the list item to brings them to detail.html ( kind of detail page ).
Now the problem i face is , on the detail page when user tabs the back button - the app goes to home.html and the homeCtrl again hits the webservice and bind the whole data once again. Which i feel is unwanted as the JSON datas was already collected on the 1st time page load itself.
How can i preserve the old data when user move back forth between different views so i no need to hit same call over and over.
Thanks and sorry if its really basic stuff.

How can i preserve the old data when user move back forth between
different views so i no need to hit same call over and over.
If you use the $http service to make the requests use the cache: true option to use the default angular cache as explained in the docs: https://docs.angularjs.org/api/ng/service/$http#caching
Here an example:
$http.get(url, { cache: true}).then(...);
You can also define your custom cache object through the $cacheFactory service: https://docs.angularjs.org/api/ng/service/$cacheFactory
If you want some more complete with expiration, size limit and other cool stuff try angular-cache: https://github.com/jmdobry/angular-cache

Hi I think that you need is create a factory or service;so in this way the controllers shared data between them.
Here's an example

Related

Cordova - Angular - <select> tag open a new view

I have an Angular/Cordova app and I'm trying to figure out how should I handle the HTML SELECT tag. What I would like to do is to open a new window with all the options in a list, the user picks one and returns with that value.
The problem is when I do that I lose all the data I had in the first screen as I am closing it when I move to the second one.
I am using Angular's UI.ROUTER. One thing, which I am not too convinced to do, is to save all data entered into StateParams, and when I return, place it back.
What would be the best approach?
It really depends on the use case. If you need to be able to "deep link" to the view where a link loads the view with the pop-up active then using ui-router and stateparams makes the most sense. If deep linking isn't a concern and the user must always select something then you can just use a service/factory/value/provider in order to share the data between the controllers during the lifetime of the app.

ionic1 wait http response of next view before load it

i'm using ionic to create an application who retrieve data from api through http request when I change view I see the view before the data of the controller totally loaded :
How can I load data of the next controller to only see the final result :
here the button who start the change of view :
<ion-item class="item-thumbnail-left item-icon-right" ng-repeat="inscription in inscriptions" ng-click="loadActiProfil({{inscription}})" href="#/app/activite">
thank you in advance
You shouldn't wait for your HTTP response to start the navigation transition, on a UX perspective. ionic provides a service called $ionicLoading which allows displaying and hiding a spinner (with a black&transparent backdrop). You may use it to make your user understand that he/she's supposed to wait. But enough with my personal opinion.
Regarding your need:
Do not use href to change the current state, you'd rather use ui-sref, as it's supposed to be done using angular-ui router (which is, of course, ionic's router too). NB: ui-sref expects a state name and not an URI (for instance, "app.home").
Use your method loadActiProfil to programmatically switch from the previous state to the new one only once your data is available, thanks to the service $state and its method go (ie: $state.go('app.home') will take you to the state app.home)
TL;DR: if you need to switch the current state programmatically, then use $state.go(stateName), not ui-sref (nor href).

How to reload the ionic view?

I have created a sidemenu based app, in that after login I am displaying a number of tasks. If I click on the task it will redirect to the task details page, in that page I can update the tasks.
So after updating a task I need to go back to the previous task list page. I am using $ionicHistory.goBack(); to go back.
My problem is after come back, I need to refresh the task list i.e. updated task should not be there in the task list. How can I refresh/reload the task list?
If you bind your task to a tasks array, which will be used in the task list page, it should be automatically updated.
But the question is about not displaying, newly added tasks (still my previous suggestion should work) if not, performance reasons ionic views are cached, So when you come back to the previous view it doesn't go through the normal loading cycle. But you 2 options
1 - disable the caching by using <ion-view cache-view="false" view-title="My Title!"> in your ion-view, but this is not a very elegant solution. read more
2 - use ionRefresher (my preferred). read more here
https://github.com/angular-ui/ui-router/issues/582
according to #hpawe01 "If you are using the current ionicframework (ionic: v1.0.0-beta.14, angularjs: v1.3.6, angular-ui-router: v0.2.13), the problem with the not-reloading-controller could be caused by the new caching-system of ionic:
Note that because we are caching these views, we aren’t destroying scopes. Instead, scopes are being disconnected from the watch cycle. Because scopes are not being destroyed and recreated,controllers are not loading again on a subsequent viewing.
There are several ways to disable caching. To disable it only for a single state, just add cache: false to the state definition.
This fixed the problem for me (after hours of reading, trying, frustration).
For all others not using ionicframework and still facing this problem: good luck!"
Hope this helps.
You can also listen to ionic events such as $ionicView.enter on $scope and trigger the code that refreshes the list if you haven't bound your list as #sameera207 suggested.
EG:
// List.controller.js
angular.module('app')
.controller('ListController', ['$scope', function($scope) {
// See http://ionicframework.com/docs/api/directive/ionView/ for full events list
$scope.$on('$ionicView.enter', function() {
_someCodeThatFetchesTasks()
.then(function(tasks) {
$scope.tasks = tasks;
});
});
});
Bear in mind that it's not the most proper way (if proper at all) and if you do this you certainly have a design flaw. Instead you should share the same data array via a factory or a service for example.
For your task you can also use ion-nav-view.
It is well documented. And if you are using now Ionic 2 beta you can use some of the view lifecyle hooks like onPageWillLeave() or onPageWillEnter(). I just faced the same problem and defined a refresh() function, but the user had to click on a button to actually update the view. But then I found:
https://webcake.co/page-lifecycle-hooks-in-ionic-2/
You just have to import the Page and NavController module and also define it in the constructor. The you can use for example onPageWillEnter(), which will always invoke when you go again to a view:
onPageWillEnter() {
// Do whatever you want here the following code is just to show you an example. I needed it to refresh the sqlite database
this.storage.query("SELECT * FROM archivedInserates").then((data) = > {
this.archivedInserates =[];
if (data.res.rows.length > 0) {
for (var i = 0; i < data.res.rows.length; i++) {
this.archivedInserates.push({userName:data.res.rows.item(i).userName, email:
data.res.rows.item(i).email});
}
}
},(error) =>{
console.log("ERROR -> " + JSON.stringify(error.err));
});
}
With ionic beta 8 the lifecylcle events changed their names. Check out the official ionic blog for the full list of the lifecycle events.
if you are building data driven app then make sure use $ionicConfigProvider.views.maxCache(0);in your app.config so that each review can refresh for more details read this http://ionicframework.com/docs/api/provider/$ionicConfigProvider/

Passing Data vs. Separate Request in AngularJS using ngResource

I'm new to angular and trying to figure out how best to accomplish this.
Say you have set up an ngResource factory to get a bunch of widgets . You return those widgets(GET /api/widgets) and display them on the page in a list.
Now say you can edit those widgets in a dialog box by clicking an edit button next to the object in the list. Is it better practice to pass the individual widget's data (that was already retrieved by the first $resource call) to the edit dialog, or simply pass an ID parameter to the dialog box and have it resolve it's own $resource call using a separate GET /api/widgets/:widgetID call.
The data wouldn't realistically change between loading the list and clicking the edit button, so it doesn't need to be synced to the exact second. Both of these requests would come from the same factory, but the question is if you should store the data and pass it, or execute a separate request.
I don't see a reason to fetch it again, I would just reuse the object.

Do we need multiple controllers to implement routes in angularjs?

There is chance that I might not be able to explain my problem properly. Let me try.
I am developing a single page application using angular. This app basically displays the episodes of an online novel series. There is a navigation bar, which has query menus (Like, latest episode, episode of a particular date, episodes with a particular tag, etc). For each of these queries, i want a separate url.
/latest - should display the latest episode
/tag/:tagname - should return all episodes with that tag.
For all these queries, the resultant view is the same (list of episodes). So I will be using the same partial for all routes.
My question is, Should I actually create a new controller for each query? like, LatestEpisodeController, TagController?
Is there anyway I can use the url to determine what the user wants and run that query from within the same controller?
Ofcourse you can use same controller in routing definition, the question is what is the purpose of that? It will be worse to debug it later, if you have a shared functionality it's better to turn it into a factory or service and then use in controllers.
But the answer is YES, you can use same controllers and implement different behaviour basing on i.e. $location.path()
yes you can use single controller for multiple routing..
you can create different functions in controller and in each function do the according job.
In my case I have created different html page for different url and registered same controller for the html pages and in the html page I have called controller method using ng-init in div portion.
You can use same controller and same views as you wish...
$location can help you to get current path or full url if you want and you can call your service depends on your path...
here I write a little example for you to get the idea
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