I have a challenge that involves setting the state of a radio button based on data retrieved from a server in AngularJS. What sets this scenario apart is the requirement to display a div based on a specific condition (when a car has exactly one user assigned to it). If the car is marked as isSingleUser, then the div containing the radio buttons should be visible; otherwise, it should remain hidden.
After some struggles, I managed to find a solution for this issue, but along the way, I encountered some interesting obstacles that I believe are worth sharing with others for future reference. I still have lingering questions about potential alternative solutions that may be more efficient.
The Simplest Solution:
In this approach, we have three cars with the Cars service retrieving the respective car based on the selected link. Only 'car1' and 'car2' are flagged as
isSingleUser, so the div should only be visible for these specific cars. The state of the radio buttons changes according to the JSON property
. Initially, I made an error by using the value property instead of ng-value, which resulted in the code not functioning as expected.car.isMonitoringAutoEnablementSetSubsequently, I tried a different method:
Magic Using Promises:
I suspected that the template was rendered before the controller received and stored the car data from the server. To address this, I added the following code snippet to the controller:
$scope.car = Cars.get({carId: $routeParams.carId}) .$promise.then(function(car) { $scope.automonitoring_state = car.isMonitoringAutoEnablementSet; $scope.isSingleUser = car.isSingleUser; });I then adjusted the view accordingly, introducing new variables:
<h1 class="title">{{car.plateNumber}}</h1> <div class='ng-hide' ng-show='isSingleUser'> <p class='paragraph'>automatic <form name="myForm" class="toggle"> <input type="radio" name="state" ng-model="automonitoring_state" ng-value="true">on <input type="radio" name="state" ng-model="automonitoring_state" ng-value="false">off <button class="button" disabled>save</button> </form> </p> </div>However, this implementation led to issues such as disappearance of plate numbers from the page, highlighting challenges related to fetching data for the
carvariable. This workaround also necessitated syncing new variables with$scope.car, making it impractical for my needs.Resolution Through Controller Scope Function:
After researching and seeking advice, I explored using
resolveto pass variables to controllers prior to rendering the view. My attempt to invoke a controller function directly from therouteProviderproved unsuccessful:when('/driver/cars/:carId', { templateUrl: 'partials/driver_car.html', controller: 'DriverCarController', resolve: 'DriverCarController'.resolveCar })I then defined the function within the controller:
$scope.resolveCar = { car: ['$routeParams', 'Cars', function($routeParams, Cars) { return Cars.get({ carId: $routeParams.carId }).then(function(car) { console.log('resolve'); return car; }, function() { return []; }); } ] };Unfortunately, this did not log anything, indicating that the function was not invoked as intended.
Another Working Solution Using Resolve:
This iteration involved a slightly modified version of the previous solution. The
Carsservice was solely utilized through the$routeProvider, where the resolved promise value was saved to thecarvariable:.when('/driver/cars/:carId', { templateUrl: 'partials/driver_car.html', controller: 'DriverCarController', resolve: { car : function (Cars,$route) { return Cars.get({carId: $route.current.params.carId}) .$promise.then(function (response) { return response; }); } } })The modification in the controller involved injecting
'car'into the list of dependencies and assigning the parameter to$scope:controllers.controller('DriverCarController', ['$scope', '$routeParams','car', 'SecurityEvents', function($scope, $routeParams, car, SecurityEvents) { $scope.car = car; console.log(car); } ]);
If you'd like to explore each solution further, feel free to check out my public plunkers available at: plunkers.
I welcome any insights or guidance on determining the most effective approach and providing clarity on the specific use cases for each alternative. Thank you!