I want my app to read a XML via internet.
Also I want to keep the previously download xml so next time I may not need to download again until certain hours is passed or whatever period of time according to settings.
Do you recommend me to download it first and store locally before process it? Or should I process it while downloading (with libxml2 I guess)?
What do you usually with apps using remote XML?
Targeting 3.0 devices btw.
The libxml2 library has a SAX parser that you can use to process XML as it comes in, to reduce memory usage. If you use the DOM parser, you have to store the entire document in memory, which can be an issue for iPhone and iPod Touch devices.
Take a look at Apple's XMLPerformance sample application, which demonstrates how to use the SAX parser. It's a bit more complicated than the DOM approaches, but it will be faster and use less memory.
Related
I'm currently developing an ios app with a lot of audio. I want to release versions in different languages but this means having all the audio in every language, which would take up too much space.
Is there a way to release different versions of the app to the different app stores, including only the relevant audio? Can this be done under one app name/id?
Thanks!
I believe that the short answer is 'no', but there are work arounds.
Each app id has one binary associated with it, although you can change the app name by localisation.
Audio is a resource, so there is no reason not to download it separately from a web server under your control. I don't believe there is any restriction on downloading media.
Alternatively, you can store the audio on Apple's servers and call it downloadable content for a freebie in app purchase.
I think you should use webservices to get the audio files from the server and get the relevant file from the server so this may help you to achieve only the relevant data in the application.
Does anyone know if it is possible to save media from the internet on the local device using Sencha Touch? From what I've seen so far, I understand it's definitely possible to save XML or JSON data locally on the device, but I have had no luck finding ways to store media locally.
To be more specific, I am looking to program an app that provides the user with a series of audio seminars - like podcasts, really. The user would be able to stream those audio files directly from the internet, but I also need to provide the user with the ability to save an episode/seminar for later. This will be important for when a user is traveling and does not have a reliable internet connection or data plan.
The primary delivery device would be on iOS (iPhone, iPad, iPod Touch) and I would hope to be able to use the same technology on Android devices - but that would be a secondary phase.
If this is possible, how would I go about saving material? And what, if any, would be the limitations on doing so? Any thoughts on this would be greatly appreciated.
I have done something similar using Sencha Touch 1 and PhoneGap to produce a hybrid app.
Basically, I use Sencha Touch to download the JSON, etc and LocalStorage to hold the data. Downloading media/files/etc to the actual device is not supported in Sencha Touch as the framework doesn't have access to a file system.
I then use PhoneGap's API's to tap into the device's native file system and download files to the app's Documents directory and pass the file names/paths to Sencha Touch for use in the app.
I'm assuming you are looking to create a hybrid app based on your question but if this is strictly a web app then there isn't much you can do.
TO add to the above point, you possibly could base64 encode the file and store it within LocalStorage but this isn't a sustainable model as LocalStorage only gives you 5mb of space. If you go over 5mb, the user is prompted (yes, no) to allow LocalStorage to use more space (in 5mb increments). Since the files your reference have the potential to be 5mb each, you can see how this could quickly become unmanageable for both you and the user.
EDIT:
See http://phonegap.com/ for the native wrapper
http://blog.clearlyinnovative.com/post/2056122828/phonegap-plugin-for-downloading-url-all-the-code for the phonegap download plugin
and https://github.com/aaronksaunders/FileDownLoadApp for the code
Check this website out. Scroll down to storing data offline. They discuss Sencha Touch provides a set of data store and proxy classes that make it very easy to work with data from (and going to) a variety of sources - both server- and client-side... hope this helped, cheers.
i want to develop an iPhone app where the app downloads data (say audio clips) from a specified server and stores it locally on the device.
then the app should use the data stored in the device rather than stream it from the server.
could anybody give me the guidelines as to how this can be done? tutorials and samples also appreciated. Thanks :)
The easiest way to play files from the internet is to use -[AVAudioPlayer initWithContentsOfURL:error:]. If you want to make sure that the whole file is downloaded, I think your best bet would be to download the file using NSURLConnection (see the URL Loading Guide) and then using -[AVAudioPlayer initWithData:error:].
Look into ASIHTTPRequest, you will find it much easier to fetch large chunks of binary over the web asynchronously than if you try to code everything yourself.
Well, I will try best not to make it as a 'I just want the code' question...
I'm recently working on a project which requires some audio signal processing from local music files (e.g. iTunes Library). The whole work includes:
Get the PCM data of an audio file (normally from iTunes library); <--AudioQueue (?)
Write the PCM data to a new file (it seems that Apple does not allow direct modification on music tracks); <--CoreAudio(?)
Do some processing and modification, like filters, manipulators, etc. <-- Will be developed in C++
Play the processed track. <--RemoteIO
The problem is, after going through some blogs and discussions:
http://lists.apple.com/archives/coreaudio-api/2009/Aug/msg00100.html, http://atastypixel.com/blog/using-remoteio-audio-unit/
http://osdir.com/ml/coreaudio-api/2009-08/msg00093.html
as well as the official sample codes, I got a feeling that the CoreAudio SDK allow us to apply audio processing only on voice demos recorded from Mic.
My question is that:
Can I get raw data from iTunes library tracks instead of Mic input?
If the first question is 'No', is there a way to 'fool' the SDK to let it think it is getting data from Mic input, not from iTunes? (I have done some similar 'hacking' stuff in C# before XD)
If the whole processing just doesn't work, can anyone provide some alternative ideas?
Any help will be appreciated. Thank you very much :-)
Thanks.
Just found something really cool yesterday.
From iPhone Media Library to PCM Samples in Dozens of Confounding, Potentially Lossy Steps
(http://www.subfurther.com/blog/?p=1103
And also a class library by MIT:
TSLibraryImport: Objective-C class + sample code for importing files from user's iPod Library in iOS4.
(http://bitbucket.org/artgillespie/tslibraryimport/changeset/a81838f8c78a
Hope they help!
Cheers,
Manca
1) No. Apple does not allow direct access to PCM data of songs. Otherwise you could create music-sharing apps, which is not in Apple's interests.
2) No. Hacking and getting approved is impossible due to Apple's code approval mechanism.
3) The only alternative I could think of is that you have to do the processing part on PC/Mac and then transfer it to the iPhone. Or you would have to store the files in your own applications folder - you should be able to load and process these via CoreAudio.
I know this thread is old but... did this work for you, Manca? And did this app get approved?
EDIT: just discovered the AVAssetReader class, introduced since iOS 4.1, should help
I want to make a small app that displays a PDF, presenting zoom-able single pages with a previous-next page function.
The Core Graphics API is pretty much the same in Cocoa and Cocoa touch. Read up on CGPDFDocument, it should provide you with everything you will need to render PDF pages. You won't need to read the PDF spec or use a library to parse PDF files directly. You will probably to learn more about Core Graphics / Quartz 2D / etc. to understand how to use those functions inside of a Cocoa app.
Based on the gradually evolving Apple policy of rejecting application submissions that duplicate functionality already on the iPhone I would worry about spending too much time even as a newbie on something that is part of the core iPhone feature-set.
This is pretty trivial. The CGPDFDocument functions will allow you to do anything you'd want to do with a PDF file.
The iPhone and iPod touch can view PDFs already, as one of the TV adverts in the UK shows an email with a .pdf attachment (of swimming lessons) being viewed. It can also view .doc, .xls, and so on, so if he is creating a viewer type application then supporting those as well could be a nice feature addition later on.
This means there is a PDF framework on these devices that you will need to access. Presumably Apple can provide support here if he is a paid up developer. Syncing the PDFs to the device is the actual real difficulty, as this isn't supported by iTunes. I assume that you would need to write a network based synchronisation tool, or have an online cloud for holding people's PDFs.
The device doesn't support Flash, so using PDF to Flash conversion tools will not work.
I found this HTML5 framework that should work on an iPad http://bakerframework.com/
but I didn't test it yet.