Problem with Angular: ng-show not constantly re-evaluating expression

Utilizing a variable named activeScope to manage the state and toggle between two forms. This variable updates its value when a tab is clicked, triggering changeScope.

While the change in active states for the tab buttons registers correctly, the divs form0 and form1 fail to toggle. It appears that there may be an issue with using ng-show, as the expression doesn't evaluate when the value of activeScope changes.

Tab markup:

<ul class="nav navbar-nav navbar-right" ng-controller="SearchScope as scope">
    <li ng-repeat="item in scopes" ng-class="{'active': isScopeActive({{$index}})}"><a href="" ng-click="changeScope($index)">{{item}}</a></li>
</ul> 

Div markup:

<div class="container main-form" ng-controller="SearchScope as scope">
    <div id="form0" ng-show="isScopeActive(0)" ng-controller="SingleIPController as sip">
    ...
    </div>
    <div id="form1" ng-show="isScopeActive(1)">
    ...
    </div>
</div>

Controller code:

app.controller("SearchScope", function($scope) {
    $scope.activeScope = 0;
    $scope.scopes = ['Individual IP Data', 'All IP Data'];

    $scope.isScopeActive = function(index){
        if(index == $scope.activeScope){
            return true;
        } else {
            return false;
        }
    };

    $scope.changeScope = function(index){
        $scope.activeScope = index;
    };
});

app.controller("SingleIPController", function($scope, $http){
    ...
});

If anyone could provide guidance on how to properly implement ng-show or suggest a solution to this issue, it would be greatly appreciated.

Answer №1

indeed, the usage of ng-show in this code snippet is not quite right. You can check out a working demo here -> https://jsfiddle.net/agm7pmyw/1/

here's the modified code:

<div id="search-container" ng-controller="SearchScope">

  <ul class="nav navbar-nav navbar-right">
    <li ng-repeat="item in scopes" ng-class="{'active' : $index == activeScope}">
      <a href="" ng-click="changeScope($index)">{{item}}</a>
    </li>
  </ul>

  <div class="container main-form">
    <div id="form0" ng-show="activeScope == 0" ng-controller="SingleIPController as sip">
      Scope 1
    </div>
  </div>

  <div class="container main-form">
    <div id="form1" ng-show="activeScope == 1" ng-controller="SingleIPController as sip">
      Scope 2
    </div>
  </div>

</div>

after making some changes to your markup, feel free to explore the demo.

Cheers!

Answer №2

Using ng-show to evaluate expressions instead of calling a function is the recommended approach. Make sure to update your code accordingly.

To implement this, create a boolean variable in your controller that tracks the selected type (0 for false, 1 for true). Then, utilize ng-show in your view to display or hide the form based on this variable.

Example Controller Code :

$scope.showForm1 = false;
$scope.changeScope = function(index){
    if(index == 0)
        $scope.showForm1 = false;
    else
        $scope.showForm1 = true;
};

Sample View Implementation:

<div class="container main-form" ng-controller="SearchScope as scope">
<div id="form0" ng-show="!showForm1" ng-controller="SingleIPController as sip">
...
  </div>
</div>

<div class="container main-form" ng-controller="SearchScope as scope">
  <div id="form1" ng-show="showForm1" ng-controller="SingleIPController as sip">
...
  </div>
</div>

Answer №3

Resolved by utilizing a strategy akin to the one demonstrated on this codepen. It closely aligns with what I was aiming to accomplish - Master-Detail pattern.

Structure -

<div class="container" ng-app="tabApp">
    <div class="row" ng-controller="TabController">
        <div class="col-md-2">
            <ul class="nav nav-pills nav-stacked">
            <li ng-class="{ active: isSet(1) }">
                <a href ng-click="setTab(1)">Home</a>
            </li>
            <li ng-class="{ active: isSet(2) }">
                <a href ng-click="setTab(2)">Profile</a>
            </li>
            <li ng-class="{ active: isSet(3) }">
                <a href ng-click="setTab(3)">Messages</a>
            </li>
            </ul>
        </div>
        <div class="col-md-8">
            <div class="jumbotron">
            <div ng-show="isSet(1)">
                <h1>Home page</h1>
                <p>Welcome to the website!</p>
                <p><a class="btn btn-primary btn-lg" role="button">Learn more</a></p>
                </div>
                <div ng-show="isSet(2)">
            <h1>Profile page</h1>
            <p>Profile information</p>
            </div>
            <div ng-show="isSet(3)">
            <h1>Messages</h1>
            <p> Some messages </p>
            </div>
        </div>
    </div>
</div>

Control -

angular.module('tabApp', [])
.controller('TabController', ['$scope', function($scope) {
    $scope.tab = 1;

    $scope.setTab = function(newTab){
        $scope.tab = newTab;
    };

    $scope.isSet = function(tabNum){
        return $scope.tab === tabNum;
    };
}]);

Style -

@import "compass/css3";

body {
margin: 15px;
}

/* text recolor */
h1, p, a {
color: #4DC9C9 !important;
}

/* button recolor */
.nav-pills > li.active > a, .btn-primary {
background-color: #6C6C6C !important;
// feeling like it's a rounded corners kind of day
border-color: #6C6C6C !important;
border-radius: 25px; 
}

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