Backbone on BlackBerry OS5 - is it possible? - blackberry

I'm developing a mobile application using Backbone, jQueryMobile and Phonegap. The app works great on Android, iOS and BB >= 6, but on BB5 as expected there are countless issues coming up.
I'm now facing problems with Backbone itself. I'm debugging it and looks like the problem is in the routes definition. The application crashes on start time due to something related to it (still investigating, but debugging is painful for BB5...).
Also, I read that BB5 won't play nice with hash listening, which Backbone relies on to do the navigation, so I am wondering if somebody has been able to create a backbone app on OS5, or is it simply not possible?

I'm updating this question just in case someone faces the same issue:
Short story: it's not possible to run Backbone on OS5. I debugged into backbone and some instructions with regular expressions were causing a crash. Even if these are fixed in the future, we determined that the js support was simply not good enough and finally discarded the OS5 version.

It is probably not worth it in most cases but this is doable.
I managed to get an app running after quite a bit of work - the javascript support is really not great in OS 5.0 and debugging is very very slow as suggested in bfcapell's answer.
To get backbone to work you need to comment out the code that uses the hashchange event to handle url changes (this is assuming that the router is being used). THere is a fallback in backbone which uses setinterval to poll for changes.
// Depending on whether we're using pushState or hashes, and whether
// 'onhashchange' is supported, determine how we check the URL state.
/*if (this._hasPushState)
{
alert('pushstate');
$(window).bind('popstate', this.checkUrl);
} else if (this._wantsHashChange && ('onhashchange' in window) && !oldIE)
{
alert('hashchange');
$(window).bind('hashchange', this.checkUrl);
} else if (this._wantsHashChange)
{*/
this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
//}
The foreach method in underscore also needs to be modified to not use the native foreach method. This is needed for collections to be rendered correctly.
var each = _.each = _.forEach = function (obj, iterator, context)
{
if (obj == null) return;
/*if (nativeForEach && obj.forEach === nativeForEach)
{
obj.forEach(iterator, context);
}
else*/
if (obj.length === +obj.length)
The above should get at least backbone mostly working. (I say mostly because I have a completely working app but I suspect to find a couple more OS5 specific issues in time).

Related

IOS Memory buildup when changing IFRAME src with angular/Embedding youtube in cordova?

I'm afraid im having the same probem as this unasnwered question.
I have a blank IFRAME In my cordova ionic IOS App for embedded YouTube videos.
I change the NG-SRC="" of iframe by clicking Next Video. But upon testing it appears that the phone/cordova/webview is caching the old content of the iframes. I can only get through 20 videos or so before crashing out of memory.
I have tried using angular.element.remove() to remove the iframe as well as setting the iframe src to blank first, and neither seemed to affect how much memory is in use, per Xcode. I've also tried the cordova plugin ClearCache and that didnt clear any memory either.
Please help! Is there a better way to embed youtube in a cordova app?
I have spent weeks working on this all to have it crashing down around me (no pun intended)
My Video view is like:
<ion-view view-title="Random Video">
<iframe id="youtube" sandbox="allow-scripts allow-same-origin" ng-src="{{video.url | trustAsResourceUrl}}" frameborder="0" allowfullscreen></iframe>
<h4>{{video.title}}</h4>
<button ng-click="nextVideo()">
</ion-view>
My controller is like:
angular.module('starter.controllers')
.controller('VideoCtrl', function(VideoService) {
$scope.video = {};
$scope.nextVideo = function() {
$scope.video = null; //doesnt seem to help
//$scope.$destroy(); //doesn't help
//angular.element(document.querySelector( '#youtube' )).attr("src", " ");
//angular.element(document.querySelector( '#youtube' )).remove();
//neither of the above 2 remove any memory
VideoService.getVideo().then(function(response){
$scope.video = response.data;
});
}
$scope.nextVideo();
});
Note, when I load my app onto a website instead, and load in chrome, I can cycle through videos without seeing the memory usage go up (looking at taskmgr.exe at least)
It might seem like setting the iframe to an empty string should be enough, but for some browsers and some situations it isn't. It might be necessary to recursively delete event listeners and elements one by one. Maybe surprisingly, the recursive method (1) below is faster than just setting to an empty string (2):
1.Recursive
while (box.lastChild) {
box.removeChild(box.lastChild);
}
2. Setting empty string
myNode.innerHTML = '';
See https://stackoverflow.com/a/3955238/1158376 for reference.
Additionally, in the recursive approach, one might need to apply special treatment to some items, for example first remove event listeners, nullify functions (http://javascript.crockford.com/memory/leak.html), and use dedicated cleanup methods, like with jQuery (http://javascript.info/tutorial/memory-leaks).
Another strategy you could try is to load a new web page with a fresh iframe for every video you play. Loading a new page should enable the browser to release the previously claimed memory.

Does sharedObject.getLocal work with Air for iOS?

So, I've created a save system for my game.The thing is it works fine on Flash and Air for desktop, but not Air For iOS when I wrap it as an iOS app.Does sharedObject.getLocal work with iOS? If not, what else can I use?
Yes, it should work. If var mySharedObject.getLocal("game") does not work, then you probably have a corrupted system, or a very old version of IOS. To be sure, post the code you're using. Also, make sure you have a correct render mode for your type of application.
2nd Option: Check your memory. If you don't have enough memory to support SharedObject, it won't store the memory. Do a test, add this code:
if(mySharedObject.size != 0)
{
textfield.text = "works."
}else{
textfield.text = "nowork."
make a textbox input called 'textfield' and a SharedObject variable 'mySharedObject'.

How does phoneGap (Cordova) work internally, iOS specific

I have started developing html applications for mutliple platforms. I recently heard about Cordova 2.0(PhoneGap) and ever since I have been curious to know how the bridge works.
After lot of code walking, i saw that the Exec.js is the code where call from JS -> Native happens
execXhr = execXhr || new XMLHttpRequest();
// Changeing this to a GET will make the XHR reach the URIProtocol on 4.2.
// For some reason it still doesn't work though...
execXhr.open('HEAD', "file:///!gap_exec", true);
execXhr.setRequestHeader('vc', cordova.iOSVCAddr);
if (shouldBundleCommandJson()) {
execXhr.setRequestHeader('cmds', nativecomm());
}
execXhr.send(null);
} else {
execIframe = execIframe || createExecIframe();
execIframe.src = "gap://ready";
But want to understand how that works, what is the concept here, what does file:///!gap_exec or gap://ready do? and how does the call propgate to the lower layers (native code layers)
thanks a bunch in advance.
The trick is easy:
There is a webview. This displays your app. The webview will handle all navigation events.
If the browser navigates to:
file:///!gap_exec
or
gap://
the webview will cancel the navigation. Everything behind these strings is re-used as an identifier, to get the concrete plugin/plugin-method and parameter:
pseudo-url example:
gap://echoplugin/echothistext?Hello World
This will cause phonegap to look for an echoplugin and call the echothistext method to send the text "Hello World" to the (native) plugin.
update
The way back from native to javascript is (or may be) loading a javascript: url into the webview.
The concrete implementation is a little bit more complex, because the javascript has to send a callback-id to native code. There could be more than one native call are running at the same time. But in fact this is no magic at all. Just a number to get the correct JSON to the right javascript-callback.
There are different ways to communicate between the platform and javascript. For Android there are three or four different bridges.
I am trying to figure this out in more detail, too. Basically there are 2 Methods on the iOS side that can help ...
- webView:shouldStartLoadWithRequest:navigationType: and
- stringByEvaluatingJavaScriptFromString:script
From the sources it seems cordova sends a "READY" message using webView:shouldStartLoadWithRequest:... and then picks up results with the second message, but I am not sure.
Cordova Sources iOSExec
There is much to learn there.

MonoTouch JIT Error in Release mode on Linq Method

I currently have some code as shown below that uses Linq to organize some IEnumerables for me. When executing this code on the device in release mode (iOS 5.0.1, MonoTouch 5.0.1, Mono 2.10.6.1) I get the exception
Attempting to JIT compile method 'System.Linq.OrderedEnumerable`1:GetEnumerator()' while running with --aot-only.
The code that generates this error is
// List<IncidentDocument> documents is passed in
List<LibraryTableViewItemGroup> groups = new List<LibraryTableViewItemGroup>();
List<DocumentObjectType> categories = documents.Select(d=>d.Type).Distinct().OrderBy(s=>s.ToString()).ToList();
foreach(DocumentObjectType cat in categories)
{
List<IncidentDocument> catDocs = documents.Where(d => d.Type == cat).OrderBy(d => d.Name).ToList();
List<LibraryTableViewItem> catDocsTableItems = catDocs.ConvertAll(d => { return new LibraryTableViewItem{ Image = GetImageForDocument(d.Type), Title = d.Name, SubTitle = d.Description}; });
LibraryTableViewItemGroup catGroup = new LibraryTableViewItemGroup{ Name = GetCatName(cat), Footer = null, Items = catDocsTableItems };
groups.Add (catGroup);
}
This error doesn't happen in the simulator for Release|Debug configurations, or on the device for the Debug configuration. I've seen a couple of similar threads on SO here and here, but I'm not sure I understand how they apply to me on this particular issue.
It could be a few things.
There are some limitations when using full AOT to build iOS applications, i.e. ensuring that nothing will be JITted at runtime (an Apple restriction). Each one is different even if the message looks identical (i.e. many causes will lead to this). However there are generally easy workarounds we can suggest for them;
It could also be a (known) regression in 5.0.1 (which is fixed in 5.0.2). This produced a few extra AOT failures that are normally not issues (or already fixed issues).
I suggest you to update to MonoTouch 5.0.2 to see if it compiles correctly your application. If not then please fill a bug report on http;//bugzilla.xamarin.com and include a small, self-contained, test case to duplicate the issue (the above is not complete enough). It seems an interesting test case if it works when debugging is enabled.

How to get a list of background processes on BlackBerry

I'm looking for something corresponding to net.rim.device.api.system.ApplicationManager.getVisibleApplications(), but including applications that might not/do not have a UI. Any ideas?
Unreasonably complicated work-around solutions welcome, I'm growing slowly more sure that there's not a simple single call to do this...
If you know the application name you can detect if it is running or not by checking the size of the array containing all AppDescriptor actually running this app.
int codeModuleHandle = CodeModuleManager.getModuleHandle(applicationPackageName);
if (codeModuleHandle != 0) {
ApplicationDescriptor[] apDes = CodeModuleManager.getApplicationDescriptors(codeModuleHandle);
}
You could imagine a code to get all installed application and then check

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