strange jQuery Mobile listview not fully refreshing - android

I have a problem with a jQuery Mobile listview not refreshing, however only in one extremely particular instance. The issue occurs when I'm testing my app on an android phone (specifically a Google Nexus). The issue occurs after my listview loads properly from view 1 to view 2. I then go to view 3. When I go from view 3 to view 2 the listview does not entirely load. What I mean by this is that it does actually load my code properly, however it is never displayed until I attempt to select one of the rows. Once I select one of the rows they all suddenly appear. I am creating my listview by appending html with javascript in document.ready(). I know this is said to be bad practice currently, however when I use the jQuery suggested method of document.bind('pageinit') it will work from 3 to 2 however everytime I leave view 2 document.bind('pageinit') is fired again. Is there anyway around this? Thanks!

One of the most important things to realize when developing with jQuery Mobile is that your javascript isn't unloaded when navigating between pages. What this in effect means is that when you use .bind() (or .on(), which is the preferred way) it is not unbound when leaving the page. This means you will have to manage this yourself.
After some struggling I found the following solution to work best for me. Load all your javascript in the <head> and create a separate javascript file which handles things like bindings. These files aren't unloaded by page navigations. An outline of this file is as follows.
$(document).on('pagebeforeshow', function(event){
currentPageId = $(event.target).attr("id");
//Give every <div data-role="page"> an id and switch on it.
switch (currentPageId) {
case "index":
loadIndex();
break;
case "fooPage":
loadFooPage();
break;
case "barPage":
loadBarPage();
break;
default:
break;
}
});
On each pageload you will bind new functions you want to that page in the following way:
function loadIndex(){
$(document).one("pageshow", function pageshow(event){
console.log("Entered the index");
$(window).on("scrollstart", someFunction);
//Unbind everything when a new page is loaded.
$(document).one("pagebeforeshow", function pagebeforeshow(event){
console.log("Exited the index")
$(window).off("scrollstart", someFunction);
});
});
}
Do this for every page you want to bind stuff to. When this is done you can execute javascript functions as you are used to, because they are loaded and unloaded on each page show.

Related

Trigger event is not working in touch devices

I've this following JS code, it's working perfectly in the desktop but it's not working in the touch devices.
jQuery(document).ready(function(){
jQuery("#gallery_trigger").click(function () {
jQuery(".my-second-portfolio").trigger( "click");
});
});
From my analysis, I figured that following line of code is not working
jQuery(".my-second-portfolio").trigger( "click");
I understand that .trigger( "click"); is not appropriate for the touch devices, so could you please help me to work this code in all devices?
Try 'tap' or 'vclick'
http://api.jquerymobile.com/tap/
$(".my-second-portfolio").tap();
The first thing you learn in jQuery is to call code inside the $(document).ready() function so everything will execute as soon as the DOM is loaded. However, in jQuery Mobile, Ajax is used to load the contents of each page into the DOM as you navigate. Because of this $(document).ready() will trigger before your first page is loaded and every code intended for page manipulation will be executed after a page refresh. This can be a very subtle bug. On some systems it may appear that it works fine, but on others it may cause erratic, difficult to repeat weirdness to occur.
Classic jQuery syntax:
$(document).ready(function() {
});
To solve this problem (and trust me this is a problem) jQuery Mobile developers created page events. In a nutshell page events are events triggered in a particular point of page execution. One of those page events is a pageinit event and we can use it like this:
$(document).on('pageinit', function() {
});
To execute a code that will only available to the index page we could use this syntax:
$('#index').on('pageinit', function() {
});
There's also another special jQuery Mobile event and it is called mobileinit.When jQuery Mobile starts, it triggers a mobileinit event on the document object. To override default settings, bind them to mobileinit. One of a good examples of mobileinit usage is turning off ajax page loading, or changing default ajax loader behavior.
$(document).on("mobileinit", function(){
//apply overrides here
});
Or you could use something like this:
$('div:jqmData(url="index.html")').on('pageshow',function(){
// code to execute on that page
//$(this) works as expected - refers the page
});
You could try to use $('.my-second-portfolio')[0].click(); to simulate a mouse click on the actual DOM element (not the jQuery object), instead of using the .trigger() jQuery method.
Note: DOM Level 2 .click() doesn't work on some elements in Safari. You will need to use a workaround.
http://api.jquery.com/click/

Android Knockout Select Problems - Chrome and Native Browser

I'm having separate but related issues relating to dropdown events in both the native and chrome browser on an android device (Samsung Galaxy Tab4).
Chrome - when selecting an item in a dropdown, the change event is fired EVERY time but the UI value doesn't update until focus is changed
Native Browser - The first time a select is changed, everything works fine. All subsequent interactions with select is as follows
--- First time an option is selected, change event DOES NOT fire and value does not update on UI
--- Second time an option is selected, change event does fire, value updates on UI
I'm using knockout with Ajax calls to fill the dropdown list. Here's the template code html (on change event here is just an alert for testing change event):
<div class="col-xs-5 col-sm-5 col-md-2 col-lg-2 search-form-label" data-bind="visibleFade: advancedSearch">
Proceeding Type
</div>
<div class="col-xs-7 col-sm-7 col-md-4 col-lg-4 search-form-data" data-bind="visibleFade: advancedSearch">
<select class="select-12" data-bind="disabled: !proceedingTypeCodes.loaded(), event: {change: onSelectChange}, value: ProceedingType, options: proceedingTypeCodes, optionsText: 'Name', optionsValue: 'Code', optionsCaption: '-- ALL --'"></select>
</div>
The view model is actually built up based on a model brought back from an Ajax call (using the json, it creates the model and binds to self. Values are brought back based on ajax requests, added to select list and loaded is marked as true. This is all called on page load
_dataService.getRemoteSiteData("Case/GetCaseStatusCodes?isForSomething=false", null, _loadCaseStatusCodes);
var _loadProceedingTypeCodes = function (data) {
_viewModel.buildModel({ proceedingTypeCodes: data }, _self);
_self.proceedingTypeCodes.loaded(true);
};
It's worth mentioning that all of this works for all other browsers, devices and platforms. We even have another site that uses this exact same paradigm for building select lists which works great (although there is only one select list on that search page whereas there are multiple ones on this page).
Anyone run into this problem?
I believe this problem is unique to Android's native browser and even when I stripped away knockout, bootstrap, etc, there was still some inconsistency.
What seems to be working is using jquery 'on' and $(this).focus methods to guarantee what you click on is in focus
$('.container').on('click','select',function(){
$(this).focus();
});
I used on as this call is in my _layout page so these inputs won't be on the page when it loads (generally) but it can really go anywhere. Very annoying bug but I think this is a decent workaround.
Related to the chrome issue, this was fixed in Chrome 40.* release

Android web view "back" button to load previously loaded div

I will try to explain this as clearly as possible. I have an android app using web view to basically load a webpage as my app. I have everything working great, however the back button seems to be an issue. I have set this page up all on one html page, it will load in a div when certain buttons are clicked to give the feel of a new page without actually having one. I basically want the back button (on the android tablet or smartphone) to load the previously loaded div, but I have no idea where to start with this. Here is what the content switching jquery looks like -
function contentSwitcher(settings){
var settings = {
contentClass : '.contentToLoad',
navigationId : '#sideMenu',
servFront : '#clickHomeHome'
};
//Hide all of the content except the first one on the nav
$(settings.contentClass).not(':first').hide();
$(settings.navigationId).find('li:first').addClass('active');
//onClick set the active state,
//hide the content panels and show the correct one
$(settings.navigationId).find('a').click(function(e){
var contentToShow = $(this).attr('href');
contentToShow = $(contentToShow);
//dissable normal link behaviour
e.preventDefault();
//set the proper active class for active state css
$(settings.navigationId).find('li').removeClass('active');
$(this).parent('li').addClass('active');
//hide the old content and show the new
$(settings.contentClass).hide();
contentToShow.show("slow");
});
}
contentSwitcher();
});
note: I've cropped out a bunch of it just to show how it works on a basic level.
Does anyone have any suggestions as to where to begin. I'd just like the back button function to be able to maybe check a started previous div name stored somewhere and load that.
thanks!
You can try using the History API. There are numerous tutorials on the web e.g. this one is quite good:
http://diveintohtml5.info/history.html
Basically this is how it works. When the user clicks the link for the div to show you push the state to the history stack.
history.pushState({<object with any information about state>}, pageTitle, newUrl);
This will push the state to the history stack meaning that when the user presses the back button on any modern browser like webkit it will take that state into consideration. When back action is taken it will then pop the state from the history stack. This action you have to listen to and handle in any way you see fit:
window.addEventListener("popstate", function(event) {
// event object contains the information from the pushed state
// do whatever needed to load the previous page here
});
The History API requires you to structure your code in a certain way for it to work well. For this I would recommend to use some existing framework that handle the back events for you e.g. Backbone.js. Hope this helps.

localStorage with Jquery Mobile works only 1 time on a new Android system

I am using the localstorage option to set a variable for using it in another page.The platform is Android
Just to simulate the problem, i just created 2 simple JQM pages and set the variable in page 1 and use it in page 2. That works fine for the first time. When i'm going back to page 1 and set a new value for the variable, page 2 tells me that it is the previous value(!). I'm a little bit lost how to use it. Can someone give me a clue how to manage this? The weird thing is that on an old Android version (like 2.3.3) it works fine, but on a new one (like > 4) it fails. I think it has something to do with ready() event?
Page 1 - Main page:
$(document).ready(function () {
$('#Klant_Lijst').delegate('li', 'click', function () { var x = $(this).data('nummer'); localStorage.setItem("Nummer", x);});
});
Page 2 - sub page
$(document).ready(function () {
GetFustInfoKlant(localStorage.getItem('Nummer'));
});
I hope someone can give me an hint in a direction. Thanks!
Please dont use ready() method, use JQM page events like pageshow, pagecreate, pagebeforeshow, etc..

Why is this onclick event not working on Android and iPhone?

I am using Prototype JavaScript library for creating dynamic drop-down menus. Before the page loads, there is no event attached to the select statements with id, id_bran and id_gen. As can be seen, the init_image is called when the page loads, and the onclick event is attached to those select statement.
This works fine in desktops where I can use a mouse to execute the click event. It however does not work in my Android and iPhone browsers. When the page loads, the init_image is called and the getval function is executed. Later however, when I make a selection in the dropdown menu, the onclick event does not call the getval function. So I am confident that the prototype library is working on my Android and iPhone as the ajax request is made on page load but it fails subsequently. What's going wrong here?
<!--
MY HTML body->onload
The init_image is called the first time when the page is loaded
-->
<body onLoad="init_image();">
//Javscript function called on page load
function init_image() {
getval();
//Assigning the event to id_gen and id_bran for mouse clicks
document.getElementById("id_gen").onclick = getsize;
document.getElementById("id_bran").onclick = getsize;
};
//Javascript function called on page load and during mouse click on the select
//statement with id = id_bran and id_gen
function getval() {
ur = 'szv/c1--'+$F('id_bran')+'/g1--'+$F('id_gen');
new Ajax.Request(ur,
{
method:'get',
onSuccess: function(transport){
var response = transport.responseText;
$('id_val').replace(response);
}
});
};
First of all, you're force-injecting events and the load event which may lead to potential cross-browser issues. If you're using prototype.js, rely on it's native methods which are cross-browser:
<script type="text/javascript">
document.observe("dom:loaded", function() {
.. your code here ..
});
</script>
Then again for properly localizing and observing the click events, instead of:
document.getElementById("id_gen").onclick = getsize;
Use something like:
$('id_gen').on('click', getsize(e).bindAsEventListener(this)); // for prototype 1.7 branch
Or:
$('id_gen').observe('click', getsize(e).bindAsEventListener(this)); // for prototype 1.6 branch
Also by setting passing the e variable there, your getsize() function will have the Event object there, so you could stop it's native behaviour (like leading to #):
function getsize(e) {
e.stop();
.. your code here ..
}
Additionally, it would be best and much less bloated if you lock your whole logic into class and create an object for it... but that's a whole different story... :)
prototype.js is a powerfull tool, but needs some care.
I would suggest you reading some basics on the framework and following the API documentation later on:
http://prototypejs.org/learn/
http://api.prototypejs.org/

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