Nativescript - how to clear a css settings in Javascript - nativescript

I'd like to clear a css setting in javascript.
e.g.
element.style.backgroundImage = ... // clear this property
Can this be done?
The problem is I use this inside a list-view element population and
since listview reuses underlying ui objects - sometimes it's set -
i'd like to reset it.

Related

Change CSS on AJAX request in Wicket

I have a component A that should dynamically change the font size of some of it's contents. I currently use CSS variables to do that and the component will contribute some CSS String containing these CSS variables:
public void renderHead(IHeaderResponse response) {
String fontCss = // dynamically fetch CSS cariables
response.render(CssHeaderItem.forCSS(fontCss, "font-css"));
}
On the same page I have the possibility to change these font sizes using an AJAX update within another component B. This will add the component A to the AjaxRequestTarget, which will cause the renderHead method to be executed with updated values for the font CSS variables.
However, I don't see an updated font size in my browser as the old CSS variables still seem to be present. How can I enforce the new CSS to overwrite the old one?
So far I found 2 solutions, that seem like dirty workarounds to me:
Add the whole page to the AjaxRequestTarget, so the whole page will be refreshed.
Add JavaScript to the AJAX update to remove the old styling with:
var allStyles = document.getElementsByTagName("style");
for (var style of allStyles) {
if (style.getAttribute("id").includes("font-css")) {
style.remove();
}
}
Is there a cleaner solution to this problem?
You found the problem with workaround 2.
response.render(CssHeaderItem.forCSS(fontCss, "font-css"));
adds <style id="font-css"> ... </style> to the page. Later when the Ajax response contributes the new content the JavaScript logic finds that there is an HTML element with id font-css and assumes that there is nothing to do.
A simple solution is to use dynamic id, e.g. by using UUID in #renderHead().
Another solution is to make this <style> a proper Wicket Component, a Label, that could be added to the AjaxRequestTarget with an updated Model when needed.

EmberJS: programmatically adding a child view to a collection view without changing underlying content

My EmberJS app is confusing me a lot at the moment. I have a collection view, that in turn defines an itemViewClass of a custom view I have defined in my code. Something like:
App.CarouselView = Ember.CollectionView.extend({
itemViewClass: App.SlideView.extend(),
});
And this CarouselView is rendered inside a template that has a dynamic segment backing it (I hope this makes sense?) . The controller for these dynamic segment is an array controller because the model for these dynamic segments is a collection :) (more confusion, please let me know)
App.SlidesController = Ember.ArrayController.extend();
By now all of you have figured that I am basically rendering a bunch of slides inside of a carousel. And these are dynamically backed in the collectionView by setting the property
contentBinding:'controller' // property set in CarouselView, controller corresponds to SlidesController
The confusion begins now. I want to add a slide to the existing set of slides. So I provide a button with an action : 'add' target='view'
In the SlidesView,
actions:{
add: function(){
var carouselView = this.get('childViews')[0];
// SlidesView has carouselView and another view as it's child, hence this.get('childViews')[0] is carouselView
var newCard = carouselView.createChildView(App.SlideView.extend());
carouselView.get('childViews').pushObject(newCard);
}
}
The above piece of code sucks and hurts me bad. I want to basically add a new SlideView to my CarouselView collection programmatically upon a button trigger. But apparently Ember recommends that childViews should not be manipulated directly and I ought to instead change the underlying content.
It states in my console.log that manipulating childViews is deprecated etc.
So essentially I need to add something to my content to my SlidesController content ? However, I don't want to add something to the content, this is just a soft add, that is providing the user with a slide so that he may choose to edit or add something if he wants to. He can always discard it. A hard add that will require me to persist the new slide to the DB will come once the user decides to save this information.

Knockout: Scrolling to one of newly inserted elements

So I have an asynchronous call to a controller in c# to obtain say 100 objects.
After this is done I load it into my html page and through a parameter in the link I intend to scroll to it.
So for instance: localhost/page.aspx?scrollToId=85
I do this as follows:
var selectedItem = $("tr[data-scrollToId='" + selectedItemId() + "']");
$('body').scrollTo(selectedItem );
selectedItem.fadeOut().fadeIn();
This works when I have static elements but because of the asynchronous call the dom is loaded way later and it doesnt scroll to it. (It does fade out and in again).
I have been looking at the afterRender method of knockout itself but this too didn't give any change.
Is there a way to wait for the actual dom to render all elements and only after this is done, scroll to it?
Many thanks in advance.
The issue was actually that afterRender only works on templates. I moved my view to a template then afterRender works.

Ember.js and Isotope.js - Executing Javascript after all childviews became rendered

I use Ember.js (1.0. RC) and would like to apply Isotope.js's functionality to some of my views located in a "container".
So my route basically loads the models containing the needed data from a server, sets up the controller's content and binds it to the model's data, which works fine.
Next I declared a template for my IndexRoute which iterates over all the loaded items like this:
{{each item in this itemViewClass="App.ItemView"}}
The items are the images that should be filtered with isotope.js. ItemView only refers to a simple template for the time being.
The execution chain is the following: Route -> Fetching model data -> Set up controllers -> Create IndexView -> Pile up all the ItemViews in a DIV-container.
Now I need to check whether all the ItemViews are loaded and the rendering is finally finished to apply isotope.js's filtering functionality but I can't figure out how to do that.
The didInsertElement of the IndexView event fires as soon as it's been rendered and before the ItemViews were added to the DOM.
I already tried to set up a ContainerView which would work in conjunction with Ember.run.scheduleOnce("afterRender"...) if I didn't fetch the data through the models but hardcoded it to the content variable.
The CollectionView also did me no favor with this exercise.
Any ideas how to solve that misery? I'd really appreciate it. Thanks.
I am not sure how exactly isotope.js works..considering its just a jquery plugin, you can call isotope like this even if it is a ContainerView or CollectionView.
didInsertElement: function() {
Ember.run.next(this, function(){
this.$().isotope({}) // or watever code u want to write
});
}
This makes sure that the code inside ember.run runs once rendering is done completely..

Can I delay loading of some controls on an xPage to after page loaded

is it possible to delay loading of some controls on an xpage?
This is the problem: let's say you have a control that does a fultextsearch and displays the result in a repeat control. this ft search might take a long time and will hold the webpage loading in a waiting state until the search result is ready.
I want my page to load most of the data initally, and some "time consuming" controls should be loaded in to the page as a sperate request after the inital load.
this way the user will immediatly see the webpage, but some of the data on the page will load a little bit later without holding the webpage in a waiting state from the server.
possible?
The downside to using rendered is that all the value bindings will still evaluate, even if the corresponding markup isn't sent to the page. So the trick here is making sure the components don't even exist until you want them to.
Every component has a getChildren() method. This returns a mutable List of components, which has a add() method. This allows you to add components to the page on the fly, either while the page is loading, or later during an event. For the purposes of what you're trying to do, you would want to defer adding the "expensive" components until a subsequent event.
Create an event handler attached directly to the view root (), give it a unique ID (e.g. "loadExpensiveComponentsEvent", set its refresh mode to partial, set a refresh ID to whatever div or panel will contain the search results, and set its event name to an arbitrary event (e.g. "loadExpensiveComponents"). This prevents your event from being triggered by actual user behavior. Set the event's code to SSJS that will inject your components.
Then add a script block () to trigger the event after the page has loaded:
XSP.addOnLoad(function(){
XSP.firePartial(null, "#{id:loadExpensiveComponentsEvent}");
});
Your page will load without the search result components. Once the page has fully loaded, it will trigger the component injection event automatically.
For guidance on how to code the injection event, open the Java file that has been generated from your existing page to see what components need to be injected and what to set their values to.
You can pack them into a panel and set their rendered status to rendered=#{viewScope.pageFullyLoaded}. Then in the onLoad event have a XSP. partialRefresh request where you set viewScope.pageFullyLoaded=true
A little ugly but doable. Now you can wrap that code into your own custom control, so you could have a "lazyGrid", "lazyPanel" etc.
Not sure why I did not think of this before. the dynamic content control in extlib actually solves this problem. the dcc can be triggered onClientLoad both using javascript and ssjs afer the page has loaded.
one problem I am facing now is that I am already using the dcc on my site so I need to put another dcc within my dcc. and this seem to be a bit buggy. I have reported it to the extlib team on openNTF.

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