I want to represent model data as different images using Angular but having some trouble finding the "right" way to do it. The Angular API docs on expressions say that conditional expressions are not allowed...
Simplifying a lot, the model data is fetched via AJAX and shows you the status of each interface on a router. Something like:
$scope.interfaces = ["UP", "DOWN", "UP", "UP", "UP", "UP", "DOWN"]
So, in Angular, we can display the state of each interface with something like:
<ul>
<li ng-repeat=interface in interfaces>{{interface}}
</ul>
BUT - Instead of the values from the model, I'd like to show a suitable image. Something following this general idea.
<ul>
<li ng-repeat=interface in interfaces>
{{if interface=="UP"}}
<img src='green-checkmark.png'>
{{else}}
<img src='big-black-X.png'>
{{/if}}
</ul>
(I think Ember supports this type of construct)
Of course, I could modify the controller to return image URLs based on the actual model data but that seems to violate the separation of model and view, no?
This SO Posting suggested using a directive to change the bg-img source. But then we are back to putting URLs in the JS not the template...
All suggestions appreciated. Thanks.
please excuse any typos
Instead of src you need ng-src.
AngularJS views support binary operators
condition && true || false
So your img tag would look like this
<img ng-src="{{interface == 'UP' && 'green-checkmark.png' || 'big-black-X.png'}}"/>
Note : the quotes (ie 'green-checkmark.png') are important here. It won't work without quotes.
plunker here (open dev tools to see the produced HTML)
Another alternative (other than binary operators suggested by #jm-) is to use ng-switch:
<span ng-switch on="interface">
<img ng-switch-when="UP" src='green-checkmark.png'>
<img ng-switch-default src='big-black-X.png'>
</span>
ng-switch will likely be better/easier if you have more than two images.
Another way ..
<img ng-src="{{!video.playing ? 'img/icons/play-rounded-button-outline.svg' : 'img/icons/pause-thin-rounded-button.svg'}}" />
<ul>
<li ng-repeat=interface in interfaces>
<img src='green-checkmark.png' ng-show="interface=='UP'" />
<img src='big-black-X.png' ng-show="interface=='DOWN'" />
</li>
</ul>
For angular 4 I have used
<img [src]="data.pic ? data.pic : 'assets/images/no-image.png' " alt="Image" title="Image">
It works for me , I hope it may use to other's also for Angular 4-5. :)
Related
I'm working on my own personal portfolio and I have my social media saved as a template to just pull from using this code in React.
{this.state.contact.map((contact, index) =>
<a className="social-icons" href={`${contact.href}`} target="_blank" rel="noopener noreferrer" key={index}>
<h3 className={`ion-social-${contact.title}`}></h3>
</a>
)}
I'm trying to create the same effect while using Vue for the ion-social-icons but I'm having a hard time figuring out how to implement it as I just receive an error talking about using v-bind:class that doesn't help much. This is what I'm currently trying.
<p class="social-media snippet ion-social-{{social.title}}" v-for="social in socials" v-bind:key="social">
{{ social.title }}
</p>
I'm relatively new to Vue also.
The error you get is:
Interpolation inside attributes has been removed. Use v-bind or the colon shorthand instead.
For example, instead of <div class="{{ val }}">, use <div :class="val">.
Off the top of my head, there are 3 ways to set an html attribute in Vue.
You want to set a string literal. Just write it as if you were writing regular HTML.
class="myClass". You cannot interpolate javascript here, which is what you're trying to do and what Vue was warning about.
You want to use a javascript variable defined in your component. Use v-bind.
v-bind:class="myClassVariable"
Same as above, where : is just a shortcut for v-bind.
:class="myClassVariable"
A working example of your class binding looks like this,
<p class="social-media snippet" :class="'ion-social-'+social.title" ...
The value inside :class="..." is simply an expression, where 'ion-social' is a string literal that's appended with the variable social.title. Once your template gets messy, which imo it is now, you should remove logic from your template and put it inside the component.
Using interpolations in HTML attributes was possible in Vue 1.0, but is no longer supported since 2.0. Here, you need to use v-bind, then add the variable with the string like you would in JS.
<p
v-for="social in socials"
v-bind:class="'social-media snippet ion-social-' + social.title"
v-bind:key="social"
>
{{ social.title }}
</p>
After having created a few different spiders I thought I could scrape practically anything, but I've hit a roadblock.
Given the following code snippet:
<div class="col-md-4">
<div class="tab-title">Homepage</div>
<p>
<a target="_blank" rel="nofollow"
href="http://www.bitcoin.org">http://www.bitcoin.org
</a>
</p>
</div>
How would you go about selecting the link that is in within <a ... </a> based on the text within the tab-title div?
The reason that I require that condition is because there are several other links that fit this condition:
response.css('div.col-md-4 a::attr(href)').extract()
My best guess is the following:
response.css('div.col-md-4 div.tab-title:contains("Homepage") a::attr(href)').extract()
Any insights are appreciated! Thank you in advance.
Note: I am using Scrapy.
How about this using XPath:
response.xpath('//div[#class="tab-title" and contains(., "Homepage")]/..//a/#href')
Find a div with class tab-title which contains Homepage inside, then step up to the parent and look for a child on any level.
EDIT:
Using CSS, you should be able to do it like this:
response.css('div.tab-title:contains("Homepage") ~ * a::attr(href)')
I am trying to build a star ranking purely in an angular template file without using controllers, I have the following code which fails, I can build this using controllers (calling setRanking method ng-click) but I want to understand why the following code is not working. User should be able to click on a star and all the stars up to the selected star should be highlighted.
<div class="item" ng-init="user_rating = 0">
<i
ng-repeat="star in [1,2,3,4,5]"
ng-class="(star>user_rating) && 'ion-ios-star-outline' || 'ion-ios-star'"
ng-click="user_rating = star"></i>
<h3>Starts: {{user_rating}} </h3>
</div>
I think the issue is with the scope of the user_rating(as it is not getting updated).
As each ng-repeat creates the isolated scope, so the way you are updating user_rating is creating a local copy of user_rating associated to the local scope of each ng-repeat.
To fix it you can replace the code
ng-init="user_rating = 0"
with
ng-init="r={}; r.user_rating = 0;"
Also refer user_rating with r.user_rating wherever you are referring user_rating.
Also the correct way of using ng-class is what #Shailendra mentioned in his answer. Thanks!
You need to make changes in this code for 'ng-class' as like below-
<div class="item" ng-init="user_rating = 0">
<i
ng-repeat="star in [1,2,3,4,5]"
ng-class="star>user_rating? 'ion-ios-star-outline': 'ion-ios-star'"
ng-click="$parent.user_rating=star;"></i>
<h3>Starts: {{user_rating}} </h3>
</div>
I Hope this may help you..
I may have worded this title incorrectly but I am hoping to still get some help. I am trying to use an expression that I get from an ng-repeat to include an new page using ng-include but it is not rendering. I can write in the page I want, but I want to use the expression to include multiple pages dynamically
<div ng-app="" id="container" ng-controller="pagesController">
<span ng-repeat="x in pages">
{{x.Page | uppercase}}
<b ng-if="!$last" href="#"> - </b>
<div ng-include="'{{x.HTML}}'" name="{{x.Page}}"></div>
</span>
But if I manually enter the pages like so:
<div ng-include="'generic.htm'" name="generic"></div>
It works as expected.
I am getting used to Angular.js obviously and I am not sure if this is possible or if I can do what I want really. Any help would be appreciated.
ng-include is an angular directive, and assuming x.HTML is a string, omit the {{}} and the single quotes:
ng-include="x.HTML"
I have a huge JSON object tree with two levels. First level has around 500 elements, and each element contains an average of 100 child elements.
I want to display the first level of the tree and I am doing it with a simple ng-repeat. When the user clicks on the element I want to display the child elements of that element. If I use a span ng-switch or a ng-show to show/hide child elements when the page first renders it freezes for around 10 seconds while generating all the HTML.
It doesn't sound like the right solution. There must be a different way of doing it, but I can't figure out. Anyone knows?
I have explained most in my comment, and here is a working plunker:
http://plunker.co/edit/RSZwfLlsCJ68MUkACbdp?p=preview
the new ng-if directive will do what you want
<h1>ng-if</h1> <h5>Click on the level to expand</h5>
<div class="well">
<ul class="nav nav-list" ng-repeat="(attr,element) in tree">
<li ng-click="expand=!expand" ng-class="{'active':expand}"><a>{{element.name}}</a></li>
<ul ng-if="expand" class="nav nav-list">
<li ng-repeat="item in element.items">{{item.name}}</li>
</ul>
</ul>
</div>
you can also do this in the "old-way" with ng-show using new ternary operator or its alternative expr && if_true || if_false
<h1>old-way</h1> <h5>Click on the level to expand</h5>
<small>use ternary operator or <pre>expand && element.items || []</pre></small>
<div class="well">
<ul class="nav nav-list" ng-repeat="(attr,element) in tree">
<li ng-click="expand=!expand" ng-class="{'active':expand}"><a>{{element.name}}</a></li>
<ul ng-show="expand" class="nav nav-list">
<li ng-repeat="item in (expand ? element.items : [])">{{item.name}}</li>
<!--<li ng-repeat="item in (expand && element.items || [])">{{item.name}}</li>-->
</ul>
</ul>
</div>
See this answer on ng-repeat performance. Essentially, it just takes a long time since Angular's ng-repeat, and basically all other directives, are set up to always look for updates in the whole JSON structure. So if you have lots of data and don't need live updates in the HTML view when changing the JSON, I wouldn't recommend using AngularJS. Generally, AngularJS performance also depends a lot on the browser and its JavaScript engine.
Alternatively, you could divide your JSON into subparts and then use pagination to display it.
I would recommend to fetch the data gradually from the server. Use server-side pagination and retrieve only the fields that you are going to display. Then, when a user clicks on one of the first level items, you can do another XHR to the server with the new data. I had similar requirements for a project and that solved the latency issue.
Regards,
Agustin.