Angular directive ng-if does not evaluate conditional statement

问题

I'm new to web dev and AngularJS. I'm trying to use the directive ng-if to only display a div block if a list returned from the database is greater than 1, but it's not working. Am I misusing the directive? I've looked around and haven't found any solutions that work. Currently, both divs are displayed and the ng-ifs are ignored.

<div>
    <div ng-if="listOfThings.length > 1">
        <h1> {{listOfThings.length}} </h1>
        </br>
        <div ng-repeat="thing in listOfThings">
           <label> {{ thing.name }} </label>
        </div>
    </div>
    <div ng-if="listOfThings.length == 1" class="col-sm-4 col-sm-offset-4">
        <h1> {{ listOfThings[0].name }} </h1>
        <iframe width="560" height="315" ng-src="{{ listOfThings[0].embed }}" frameborder="0" allowfullscreen></iframe>
    </div>
</div>

I tried this code, which works in Plunker, but not in my code for some reason. In my code, only ng-app works, but ng-if still does not.

    <div ng-app="ngAnimate">
        Click me: <input type="text" ng-model="check" ng-init="check='show'" /><br/>
        Show when check: {{check}}
        <input ng-if="check!='hide'" class="animate-if" placeholder="type the word 'hide'"/>
    </div>

回答1:

What you want instead of this ng-if="{{listOfThings.length}} > 1" is this:

 ng-if="listOfThings.length>1"

ng-if will evaluate the expression.

Check this Online Demo

回答2:

This should do

<div>
    <div ng-if="listOfThings.length > 1">
        <h1> {{listOfThings.length}} </h1>
        </br>
        <div ng-repeat="thing in listOfThings">
           <label> {{ thing.name }} </label>
        </div>
    </div>
    <div ng-if="listOfThings.length == 1" class="col-sm-4 col-sm-offset-4">
        <h1> {{ listOfThings[0].name }} </h1>
        <iframe width="560" height="315" ng-src="{{listOfThings[0].embed}}" frameborder="0" allowfullscreen></iframe>
    </div>
</div>

来源：https://stackoverflow.com/questions/23937383/angular-directive-ng-if-does-not-evaluate-conditional-statement

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angularjs

angular-ng-if