Hide navigation bar on scroll with animation Titanium - javascript

Some apps (facebook, 9gag) have this functionality. When the user scrolls up the navigation bar gradually hides itself to a point where vanishes. Then when the user scrolls down the navigationBar gradually shows itself (depending on the speed of the scroll).
We tried to implement this on Titanium by adjusting the height of the nav view on the scroll event, but it is lagged and very slow:
scrollView.addEventListener('touchstart',function(e){
boolScroll=true;
});
scrollView.addEventListener('scroll',function(e){
if(boolScroll){
auxScroll=e.y;
boolScroll=false;
}
var bh=bars.height;
var sh=scrolls.height;
if(auxScroll<e.y)//scrolling down
if(bars.height>appHeight*0.08){
bars.height=bh-appHeight*0.005; //rate for hiding
if(scrolls.height<appHeight*0.7)
scrolls.height=sh+appHeight*0.005;//same rate to increase the height of the scroll
}
if(auxScroll>e.y)//scrolling up
if(bars.height<appHeight*0.08){
bars.height=bh+appHeight*0.005;
if(scrolls.height>appHeight*0.7)
scrolls.height=sh-appHeight*0.005;
}
});
We also tried doing it with translate animation on the view, but is still slow.
There is a solution for iOS on this question. Any help would be appreciated!

Don't know if you solved this problem but I did a trick that's working well for me ( at least for the navigation bar )
Here's the snippet :
self.addEventListener('scroll',function(e){
if(e.contentOffset.y > 20) NavigationWindow.window.hideNavBar();
if(e.contentOffset.y < 20) NavigationWindow.window.showNavBar();
});
NavigationWindow is an instance of Ti.UI.iOS.createNavigationWindow, self can be a tableview,view,scrollview or a window ( in my example )

this is actually a really nice feature to have. Appcelerator just tackled it and should be available on release 6.0 according to this ticket: https://jira.appcelerator.org/browse/TIMOB-23684

Related

Darkening <section> on one-page website

I am a semi-noob at web dev, however I am either searching with the wrong terms or I am not a very proficient googler.
I am making a one page website and want the effect that when a new section comes into view scrolling down, that the new section will darken. I can achieve darkening on mouse over, but I want the currently visible section to always remain dark until navigating away from it, not only when the mouse is hovering over the section.
I am thinking it may have to be JS as I cannot seem to find what I need in CSS, but perhaps the collective mind can help!
Cheers!
This is a little push in the right direction: http://jsfiddle.net/f5w35qu8/1/
$(window).scroll(function () {
var scrolled = $(window).scrollTop();
if (scrolled > 10) {
$('section:first').addClass('darker');
}
else $('section:first').removeClass('darker');
});

SnapJS Mobile Menu Positioning

I'm trying to setup a Wordpress starter theme with an out-of-the-box mobile menu. I'm using SnapJS to create a slide out menu.
It's working fairly well - almost perfectly but I've run in to one issue that I just cannot fix.
You can find the menu in it's current state here: http://sandbox.benpalmer.me/flow/test/
The problem is that if you scroll down the page (in a browser width less than 700px) then hit the menu button, the menu will slide out but the content (in #wrapper) will jump back to the top.
I know precisely why this is happening - the positioning switches to fixed with a top set to 0px.
I've got the following JS setup:
snap.on('open', function() {
wrapper.css({
'top': '-' + $('body').scrollTop() + 'px'
});
});
This almost does what I need but it basically jumps to the top and then scrolls down to this position.
I'm fairly sure in saying that this animation is coming from Snap but I'm really not sure what to remove or alter. Or even if there is a simple way to disabled this from happening?
Any help would be hugely appreciated! Thanks!
I found the offending line in SnapJS and fortunely it means that to fix this, I didn't have to edit SnapJS itself.
settings.element.style[cache.vendor+'Transition'] = 'all ' + settings.transitionSpeed + 's ' + settings.easing;
The fix was to set the transitionSpeed setting to 0. Now it still applies the transition but as it's set to 0 it's obviously not noticeable.

Using javascript to pause background scroll to allow for fixed elements to have slide show

Ok so the effect I am trying to emulate can be found on the nexus 5 site - http://www.google.com/nexus/5/ - when you scroll to the phone section. I've viewed source and looked through the code but there is over 13k lines of js so it was a waste.
Anyways what I did was add a class to fix the position of the images and created a background div that was like 5000px so it would appear to be fixed. The js fixed the position after the screen reached a certain point and then removed the fixed class after the end of the div.
My question is that i know this can be done better than my janky 'hack'. I'd love to hear your thoughts on better implementation.
This is part of the code that adds the fixed class
<script type="text/javascript">
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= 500) {
$(".container").addClass("fixed");
}
if (scroll >= 8000) {
$(".container").removeClass("fixed");
}
});
Try this guide:
http://blog.teamtreehouse.com/multiplane-design-with-svgs-and-css-3d-transforms
Demo: http://codepen.io/nickpettit/full/eBCrK
Haven't done something like this before myself however. Also just a note that fixed position elements from my experience act up when viewed on tablet/smartphone.

scrolling on mobile devices

This question is more of an advice research, I do hope that it will be helpful for others and it won't closed, as I'm not quite sure where to ask for advice on this matter.
I've been developing for mobile for the past 6 months and I had the occasion to deal with all kinds of situations and bugs on various devices.
The most troubling was the scrolling issue, when it comes to scrolling in multiple areas of the website. On three projects that I have been working on I've been building a navigation that behaves the same way that the native iOS Facebook app has, or the Google website on mobile, etc. And for each one I came up with different solutions.
But a few days ago I have just released a new JavaScript library, drawerjs, that can be used to generate such navigation (so called off canvas concept). The difference between the other libs and this one is that is library agnostic, and it acts on touch behavior (the same way that the Facebook app behaves) not just open / close on click.
One of the things that I have left to implement is a solution for scrolling inside the menu and the navigation without affecting one another (most of the time when you scroll in such way, the content tends to scroll together with you menu or after you have reached the end of the menu scrolling).
I have two solutions in mind:
One approach would be to use the same principle I'm using for dragging the content and showing the navigation, on touchmove I prevent the default scrolling on document / content and I start translating the contents with the same amount you scroll. And with the same resistant behavior as a touch slider would have (when you exceed the boundaries and let go, the contents would translate back so it doesn't exceed the boundary anymore, or on swipe with the same behavior).
A second approach would be using the native overflow-scrolling that iOS has and would offer the same feel as described in the first approach. The downside of this would be that only iOS devices would have the nice resistant feature, but it would be, supposedly, less of a hassle the the first approach.
So I'm not quite sure which approach I should take, or if there any better solutions for that. I'm also trying to keep in mind that some users would like to hide the url bar, so scrolling on the body / html would have to be kept (on the y axis).
You could do touchmove . But as far as I understand, you want something like this?
http://jsfiddle.net/2DwyH/
using
var menu = $('#menu')
menu.on('mousewheel', function(e, d) {
if((this.scrollTop === (menu[0].scrollHeight - menu.height()) && d < 0) || (this.scrollTop === 0 && d > 0)) {
e.preventDefault();
}
});
Using this plugin from Brandon Aaron - github : https://github.com/brandonaaron/jquery-mousewheel
And it should work with Android: What DOM events are available to WebKit on Android?
Some more info here: Prevent scrolling of parent element?
Also without using the plugin above , using only jQuery you could do this like it says on the link above - answer from Troy Alford
$('.Scrollable').on('DOMMouseScroll mousewheel', function(ev) {
var $this = $(this),
scrollTop = this.scrollTop,
scrollHeight = this.scrollHeight,
height = $this.height(),
delta = (ev.type == 'DOMMouseScroll' ?
ev.originalEvent.detail * -40 :
ev.originalEvent.wheelDelta),
up = delta > 0;
var prevent = function() {
ev.stopPropagation();
ev.preventDefault();
ev.returnValue = false;
return false;
}
if (!up && -delta > scrollHeight - height - scrollTop) {
// Scrolling down, but this will take us past the bottom.
$this.scrollTop(scrollHeight);
return prevent();
} else if (up && delta > scrollTop) {
// Scrolling up, but this will take us past the top.
$this.scrollTop(0);
return prevent();
}
});
The JS Fiddle he mentions: http://jsfiddle.net/TroyAlford/4wrxq/1/
Why not just provide a fixed height to your widget (min and max will also do). Then define like these -
height: x px;
overflow-y: auto;
This way till the focus is inside the widget, it'll only overflow the widget, once outside the page will scroll without affecting widget content at all.

How to create a dynamic navigation bar which follows you when you reach certain location

I want to create a navigation bar similar to this site's:
http://www.mysupermarket.co.uk/#/shelves/top_offers_in_asda.html
Can anyone tell me how to create that navigation bar, which follows you as you scroll the page down, but not following you at the initial loading of page?
When you access to the given website, try to scrolling down and you will understand what I am talking about. The navigation bar that consists of MY SHOP, OFFERS, IDEAS & LIFESTYLE, BAKERY and so-on...
I have really no idea what it's called. At least tell me what it's called, so I'll be able to search.
Here is the solution I've done
window.onscroll = function(){
if(getScrollTop()>140) {
document.getElementById("menu").style.position="fixed";
} else {
document.getElementById("menu").style.position="";
}
}
function getScrollTop() {
if (window.onscroll) {
// Most browsers
return window.pageYOffset;
}
var d = document.documentElement;
if (d.clientHeight) {
// IE in standards mode
return d.scrollTop;
}
// IE in quirks mode
return document.body.scrollTop;
}
Holding an element on same position can be achieved by fixed position styling.
If you want your navigation bar to stay on exact same location, position:fixed; is enough. (At least non IE6)
You can find a working example and some details here
However, if you want your navigation bar to move from it's initial location to the top border of page as you scroll the page down, you must implement some JavaScript to catch page scroll event and move the <div> accordingly.
See this question for an example on how to do that.
Note: this won't work with the Android 2.3 browser; position:fixed will not behave as expected - it kinda of temporarily attaches its position to the scrolling element before jumping back to the top.
if you want you could just set the z-index to be a specific No. and that should work.
example
z-index:100;

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