Android Expansion apk - android

I was going through the docs of APK EXPANSION FILES in android and I was wondering that can we have all layout files in the patch apk and application's business logic in main apk ?
I read this Android Apps Break the 50MB Barrier too.
I tried creating this but the problem I faced was our widget names need to be in R.java file which is generated automatically..If I have layout files in patch file not in the main file then I am unable to refer then using R.id.xxx.
So Please tell me if this is possible or not ?
If this is possible then how it can be achieved ?
I also want to know ,what are the resources or assets that can be added in the patch apk.

Speaking straight, It's not possible to separate the layout files from apk and then trying to access it using R.id.whatever
Expansion files are meant to store the assets such as media, docs, and other such static things which your application uses and the content of the expansion pack is stored on device's shared storage and is not linked with the apk file. To access the assets of the expansion file, you must code your application to read them from that device's shared storage location.
Coming back to the question of storing the layout files in an expansion file. To achieve this, you will have to write your own layout parser with the basic functionality similar to LayoutInflator. You can not use LayoutInflator to parse any layout file which is not part of the apk or stored on any external storage. So the idea is to store your layout files in the expansion file (which will be out of apk, on device shared storage), parse the file using your own parser, and add the views to the main layout at runtime. Though you wont be able to access your views using R.id.whatever but you can always use visual tree to access the views or while parsing the views store the referenced objects to access them for later use.
Hope this gives you a starting point.

Related

Where should I store local files for a WebView

Lets say I want to store a JavaScript file in my app for an Android WebView to use. Where should I put this file? My first though would be somewhere in the assets folder, but I am not too sure.
Check the following link and explanations:
http://www.41post.com/3985/programming/android-loading-files-from-the-assets-and-raw-folders
The Assets folder is an 'appendix' directory. The R class does not
generate IDs for the files placed there, so its less compatible with
some Android classes and methods. Also, it’s much slower to access a
file inside it, since you will need to get a handle to it based on a
String. There is also a 1MB size limit for files placed inside the
Assets folder, however some operations are more easily done by placing
files in this folder, like copying a database file to the system’s
memory. There’s no (easy) way to create an Android XML reference to
files inside the Assets folder.
There is also a raw folder you can even use that, but:
it’s important to highlight the main differences between the raw
folder and the Assets folder. Since raw is a subfolder of Resources
(res), Android will automatically generate an ID for any file located
inside it. This ID is then stored an the R class that will act as a
reference to a file, meaning it can be easily accessed from other
Android classes and methods and even in Android XML files.
Using the
automatically generated ID is the fastest way to have access to a file
in Android.
For completing the answer, you can easily use file:///android_asset/
Have a look at this question:
Android WebView Javascript from assets

Using google play expansion files

I've just finished an app which is about 100MB and I need to use expansion files for the first time.
I've looked through this tutorial http://ankitthakkar90.blogspot.co.uk/2013/01/apk-expansion-files-in-android-with.html, but I don't understand the concept of expansion files and looking for a bit more clarification.
What exactly are the contents of these expansion files? For example my app using alot of images and videos are these what need to go in my expansion files.
If the above is correct does that mean I need to take them out of my project, change my code were I have referenced these resources directly from my drawables and instead reference them from memory?
If both the above are wrong then what exactly goes in the expansion files and what happens to the apk which is already over 50MB.
I'd really appreciate any help explaining this.
1) Expansion files can have any assets that you use in your app (videos,audio,images,text files etc).
2) Yes, your expansion files are extracted inside the external storage of the device.. you should update all your references to get the data from there.
http://developer.android.com/google/play/expansion-files.html
The above link has it all explained (naming to use, how to debug ) etc.

Android load and modify file

I have a short question about writing to a file in android. I am writing a game where I use a xml file to save some data about the level stats. Now I have seen that if I save this xml file in AssetManager it is not possible to change it (only permissions to read files).
Now because I can only modify files which are in the filesystem of android (using openFileInput and openFileOutput to work with it) I wonder where I have to save my (already existing) xml file in my eclipse project so that I can use openFileInput to load it and change it via code.
Do I have to make a new folder? E.g. project_path/files/myxml.xml.
Is it even possible to load a file which was created (outside the AssetManager folder) before installing the .apk to target?
If it is possible does anybody have some example code?
I hope you understand my question.
There is no such place. Installation of android apps does not include an automatic step that would copy your content from apk to the internal folder (and your application does not reside in the folder either).
You will have to create your XML file in code, possibly checking for its existence before each access (or using some other marker).

Choosing the right data storage alternative

I'm coding an android app for parsing sms messages. I need different rules for different countries and idea is to define rules for my country and later open source project so other users can contribute with rules for their countries. XML format is the most convenient in my opinion for defining these rules.
So I have an app which reeds rules from XML file stored in res/raw and users will later be able to update that set of rules or download rules for some other country when those become available.
As I said I have put existing XML files in res/raw, but the problem is when users download new or changed set of rules application can not change or store files in resources (correct me if I'm wrong).
So I have two options now, and I don't like either one. I would like to hear your opinions on the matter.
a) I can keep XML files as local files, but then I must read in default rules from res/raw and copy them into file system on application installation, or keep track of two separate bunch of files. Is it possible to preinclude files on file system when installing an app?
b) I can keep XML code in database, but also copy it from files at install time. Or even worse code XML as String in class to insert it on install?
I apologize if question is too long or unclear, English is not my native language and this is my first question.
I'm not sure if i understood you right, but you could store the XML-file in the internal data storage of the application. --> http://developer.android.com/guide/topics/data/data-storage.html
If you want to attach a first Version of the XML-file on install, store it in the ressources first and copy it to the internal data storage after install. On updates of the XML file you can just overwrite this file in the internal data storage.
Hope i could help you, this is my first answer on stackoverflow. I'm sorry if i just told you things you already knew.

What is best practice for shipping editable XML with your application?

Hi fellow android developers!
I am developing an application where I have XML files that contain my data. When doing edits in these data, I save the data to the XML files, thus these must be editable.
This I would be able to achieve using the local storage for my application with the openFileOutput method of my Context.
But how would I go around shipping my program with these datafiles already there, with some pre-filled data?
I can see the option of shipping with some XML files in my res/xml or res/raw, duplicate them to the local data storage, but then I would be unable to remove the files in my resources, and this would take up too much storage.
Please tell me what you would do in this case?
You can not include editable files with your application.
So you will have to write them to the local file system some way. Either by downloading them or including them as raw resources via openRawResource().

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