Develop Reference

Can I change a string in the strings resource file to one from array in an activity?

Been having a little bit of trouble with this. Googled about and I can't really find anything. Saw a few things about setting text but I don't think that affects the string resource file or at least I can't make it affect the resource file. Help please!

No, you can't modify apk at the runtime. If you don't own source code, you can pull apk file to the computer and decompile it by using APKTool, for example. If you are working with data you get from internet/user, it should be kept inside DBs, files, whatever. In other words in internal or external storage. Please take a look on storage options you can use http://developer.android.com/guide/topics/data/data-storage.html

how to determine the extension of a file

I'm fetching byte array from server but don't know the exact extension of the file because that file could be .pdf / mp4 / docx / zip, so how would I know the exact extension after saving it to sdcard.
Any idea?

There's no way to reliably determine the file extension from the file contents. It's like trying to find out what was written on an envelope, if all you have is the letter itself.
You could guess, but that would be a difficult task (for example, a docx is also a zip file). There is specialized software for this (many operating systems include the file tool), and you might find a third-party library that you can use, but even if you do that, it's still a guess.
I'd rather concentrate on finding a way for the server to tell you the original file name in addition to the contents.

There is no proper way to determine the file extension right away.
However you can impose conditions for the specific file types like if the file extension is mp3 then do the certain task. For that you can use FilenameFilter.
Check the how-to-find-all-files-with-certain-extension-on-android for more information about it.

If it is custom protocol, you should pass one(or more) byte of data type to the client side, then you get data and add extension on the client side according to the first byte(s). If it is http-like protocol, you can add some header to the answer. But it is need to do as on the serverside as well as on the clientside too.

Dynamically Determine Android Resources

I have a number of different string resource files that are built with my Android application using our build system. These string files can be added incrementally at any time and our build system will pick them up from their separate directory. I want to enumerate all of the string files or be able to obtain a single string in them without having to know the name or id of the string resource in them. I also don't want the person adding these to have to edit a main string file in my package that includes an array listing the different files. Is there any way to accomplish this?
Example:
SoccerStrings.xml
id="SoccerDetails" value="soccer"
CricketStrings.xml
id="CricketDetails" value="cricket"
Without knowing these files exist how can I provide a list view with two items: Cricket and Soccer in addition to automatically supporting any additional files that might appear.
I was thinking the best possible approach would be to have the build system pull the individual files under assets folder and then use the getAssets().list("") functionality along with the XMLResourceParser class to access the string values. Would this work and allow me to have id conflicts (ex: id="name")? Is there an easier way?

I would look at aapt. I know you can get the resources out of the .apk with the following command --
aapt d --values resources app.apk
It might be possible to use aapt to get the resources earlier in the build process. It has the following option which looks prosmising, but aapt documentation is a bit thin.
--output-text-symbols
Generates a text file containing the resource symbols of the R class in the
specified folder.
As another alternative, you could modify your build process and parse the string class directly out of the gen/<package>/R.java file after it has been generated. You could store that in a loadable file, or generate your own source file to add to the build.

I am not going to tell you how to do it. I am answering the question to advise against it.
What you are planning to do does not go well with the resource files. These files are basically code. What you want to do is about data. You should have your data in assets directory. Then these files won't be precompiled in your build like the resource file. You can process these files any way you want. There will be then quite a bit coding involved to convert all that into business logic, but that would be price to pay to write good, maintainable code.
Playing with resource files the way you are suggesting is akin to Java reflection. You want to use it only because you have functionality that is about such feature, not because it's the easiest way out.
Having said that, you might be exactly in a situation where you have to handle the resource files the way you stated. In that case, please accept my apologies.

Creating a file on an Android device

I am new to Android development using eclipse, although not new to software development in general.
For my first real project, I am trying to modify the example SoftKeyboard that is supplied with the SDK. I want to modify one of the keys to act as a function key, when followed by a single letter key it will enter a canned string - performing a macro function.
So far so good. I have the key and graphics modified, and found where to respond. I would like to put the canned strings in an editable Properties file stored where the keyboard can find them.
That is where I'm having trouble. It seems that I can't to create and save a file. I don't know if it's read/write permission problem, whether the keyboard (it runs as a service) is not allowed to create a file, or my code is just plain wrong.
Can someone help me out – point me in the right direction?
Thank you very much.
Barry.

If these are canned files that come with the APK you install to the device and only need to read (not write), you can place them in the assets folder of your project. Then use the resource manager to load them:
Resources resources = getResources();
InputStream moduleSearchTemplateIn = resources.getAssets().open("file/name/here.properties");
If you want to read/write files on the SD card, you'll need to add a permission to your manifest. Though, for this purpose, I'd probably prefer a SQLite table.

Android writing to a text file

I have a text file within my raw folder of my app that I intend to use as a simple way to save settings and then read them back when needed. I can read from this file with using the BufferedReader and what comes with it, but I've tried a few different ways to be able to write to this file and none seem to work.
It seems to me that the problem is I never actually get the file, and I assume this is simply because I don't exactly know how I am supposed to give it the correct directory and file name. I've tried all I could come up with, and I tend to get errors like "No such file or directory exists" or "Read-only file system".
This seems to be a very simple problem relating to me just giving the wrong information, so if anybody could point me in the right direction it would be much appreciated.
Thank you,
Raphy

For saving settings you should use SharedPreferences rather than coming up with a custom solution.
SharedPreferences documentation
Data Storage

I'm not entirely sure you can do that with stuff in the "raw" folder.
One approach would be to use the SharedPreference storage in the API. See in the datastorage section of the docs. It's perfect from what you describe neededing. Another approach would be to put the file on the SDCard and read and write it from there.