I am trying to write a modular extensible application to deploy in Android. The idea is to provide an API to allow the creation of custom functionality for the app that may include custom layouts and other resources. This custom functionality will be loaded, at runtime, from another location (e.g. SD Card).
Currently I am able to load .jar files from this location and work with them as I like, unfortunately I can only include references to layouts and resources that are also present in the "Main" project.
I have been unable to find a good way to reference an entire library project, resources included. I essentially want each custom piece to contain all the resources it needs to display and run itself.
Right now I am toying with the idea of including an "Assets" project that can be referenced by each of the modules to be a central area to store layouts and other resources. Unfortunately this would require me to have a project that must be loaded by any other project that needs to be built.
Another idea was to include the layouts, images and strings, along with the jar files, in a folder and load those at run time. I don't think this will work well since the layouts seem to be pre-processed at compile time in some way and cannot be inflated at run time.
Does anyone know a way for me to include all the resources and code into a single, dynamically loadable, file that I can then access at runtime?
Does anyone know a way for me to include all the resources and code into a single, dynamically loadable, file that I can then access at runtime?
That is not supported. It is rather likely that it will never be supported, though it is possible that it might work with the new build system that is under development.
Related
I am creating three apps that are almost the same except some changes in the assets and raw files between them.
So I wanted to create a library from the first one, that will contain all the logic and activity and all the layouts and resources, and then import this library to the other two apps, and only change the assets and raw files.
the problem is that when the layout from the library loads, it is loading the assets from the library itself, and not the assets of the main app.
I am sure that my design here is wrong then I would also appreciate if someone can explain to me what is the right way to share activities and layouts as libraries in android.
NOTE: I don't want to use flavors. I want to build it as a completely different projects.
cheers
Im thinking about trying to build a complex android app structure for a game maybe or just for practice reasons. Im used to code in objective-c, so im not that much experienced in android...
Anyway in work, we structure our app on ios like this:
-core framework: handling all core items, navigation, datahandling, mechanisms, etc. its the same in all of our project
-project framework: its files are mostly relying (including) the core framework's files, extending/modifying them, and doing the project depending stuff
-skin framework: this contains all the resources and images, if we want to do a re-skinned project, we only have to alter this
-main project: this includes everything just bashing together everything into an app. just starts the application, nothing more, anything else is done by the different frameworks
So I wanted to do a similar structure on android, but I'm not sure that I'm even able to do it... I see that there is android project and library project, I can include them into eachother... but my questions are:
1: can I build a similar structure as on ios?
2: can I make for example a "core" library what contains the basics of mechanisms, and another library containing only the resources, and a third one (or the third could be the actual runnable project), what can get resources from the resource library, can distribute jobs to the core library, etc...
3: can I organize the resources as I like (so not to throw every picture into the drawable folder root for example). For example to have somehow a characters folder (i know i cant do forlders in the res folder), and map files into map folder, etc... My only chance to name them "properly"? (map_sheet_type_1, map_sheet_type_2, character_sheet_type_1, etc) (if its going to be a game, it would use opengl, lots of sprite drawing, etc)
or I should do everything in a single project, dividing everything into a lot of packages, and use libraries only for jobs like "how to transcode "A" object into "B" object" ?
Thanks for the answers in advance
although I've never developed a game before, but an app is an app:
yes
as you mention you have executable projects and libraries projects, libraries can use other libraries and the only thing that goes to the device is whatever the executable project is building. It's just important to remark that compiled libraries *.jar files resources cannot be used in your executable project (that's why the ActionBar Sherlock have to be used as a library-project). In order to use a resource placed in a library project the project must be with its full source code open in the Eclipse so it can be compiled together. That is because inside an app, there's only one R (resources) object, and during build all the resources from all the projects are put together.
unfortunately no. As you mentioned yourself the resources cannot be in subfolders and even their file names are restricted as they can only use lower case letters, numbers and _ (underline). Just be clever and organised, write a spec or something.
packages IS the way to organize a single project in Java. If you gonna use multiple or single is your choice. Usually you can encapsulate in a library-project stuff that can easily be re-used in different projects, and the final project will contain everything that is specific to that one app/game. I'll give you an example on the place I work, we have a KicthenLibrary that is a library-project that we use in every single Android app we do. That library already contains an excellent multi-threaded bitmap download and cache classes, we used to have a MapFragment (now deprecated) before Google released their MapFragment, easy Http GET/POST methods, etc. As you can see, all of those are stuff that can easily be re-used in several different projects.
And just as a last trick, http://www.eclipse.org/egit/ IMHO is much easier to use GIT directly from inside Eclipse.
Here are a couple links that should help you get started on this.
http://kasperholtze.com/android/how-to-best-organize-your-android-source/
http://bartinger.at/organization-tips-for-android-projects/
Also, when I worked at a start-up, we made an app for both iOS and Android. We started creating native apps for each, and ended up having somewhat different structure. Global information/variables were handled different, and I couldn't structure my files quite like iOS did. That said, Android structure isn't terribly hard to figure out, and I made a fair amount of sub-folders in my assets folder (for libraries and js and such). And yes, you can definitely have several libraries.
As for having several projects in several in one app, see this link How to create a single application from multiple Android projects
The standard advice for sharing code & resources between Android projects is to use a library. Personally I find this works poorly if (a) the shared code changes a lot, or (b) your computer isn't fast enough.
I also don't want to get into deploying multiple APK's, which seems to be necessary when I use dependent projects (i.e. Java Build Path, Projects Tab).
On the other hand, sharing a folder of source code by using the Eclipse linked source feature works great (Java Build Path, Source tab, Link Source button), but for these two issues:
1) I can't use the same technique to share resources. I can create the link to the resources parent folder but then things get wonky and the shared resources don't get compiled (I'm using ADT 21).
2) So then I settle for copying the shared resources into each project, but this doesn't work because either. The shared code can't import the copy of its resources because it doesn't know the package name of the project that uses it. The solution I've been using is to access the resources dynamically, but that has become cumbersome as the number of resources grows.
So, I need a solution to either (1) or (2), or I'll have to go back to a library project. (Or maybe there is another option I haven't thought of?)
Your real problem is (2). Fixing (1) would eliminate some copying, but you would still run into problems with (2).
Unfortunately, that really isn't possible. There's a fair bit of fancy footwork that goes on to make multiple packages possible with library projects, and there's no good way to get that same result without library projects. Anything in res/ of a project is accessed via that project's R class, including your copied resources.
The solution I've been using is to access the resources dynamically
I translated that into you using getIdentifier(). That certainly works. Another approach is to having the hosting app supply resource IDs as parameters to the library code -- this is the pattern that the Android SDK itself uses. This is faster at runtime than the reflection-based getIdentifier(), and it gives the hosting app somewhat more flexibility, but you do wind up adding a bunch of parameters to your methods and constructors as needed to supply the various project-specific R values.
I am trying to use the DexClassLoader to download a JAR/APK in my app. I would like to modularize my app so I can download UI flows the user might go on demand instead of shipping them all together into my main app.
Loading the actual classes works fine and I managed to load some UI components which I can add to my host activity.
My problem is that obviously I cannot access or add resources (Strings, drawables, layouts) to my downloaded package because they do not come with my host APK. Is it possible to dynamically load resources for my downloadable JAR/APK?
You can "dynamically" download any resources you want, put them in a directory you choose, and use them in your app. It's what I currently do in an app. I don't think you can put them in the same directory with the resources that are in your project, but does that matter?
I have an app on the iPhone and need to port it to android. For this I would like to group screen related files like classes and xml per screen in one "screen group" per screen somehow, ideally also strings and other value files
if I use folders I can only group res files separately and src files separately.
what would be the best way?
Thanks very much!
EDIT:
If that should not be possible, how to best then solve this issue? Do you create a subfolder in the src and another in the res for each screen?
The way you group files for the iphone is not possible for an android project. Android has pre determined folders which hold specific files, if you break this structure, your building process will fail. Its not ideal but that just how it it.
When it comes to source java files, they follow the concept of packages which are basically folders. The 'src' folder is the part where you can create sub folders as you desire. If you are adamant about keeping the files related to a screen in one place, you should create the layouts with java code and not use layout xml files.
But using xml layout files make development much easier and faster. Consider that as the presentation and java files as the logic+data. So group java files as you want and leave xml files in the layout folder with easy to identify names.
android uses certain directory layout for project structures (i.e. convention over configuration). Basically you will want to put your XML layout files in res/layout directory. Please read http://developer.android.com/guide/developing/projects/index.html#ApplicationProjects for further information.
Unfortunately, there's no easy way to do this in Eclipse. You can't create custom directories in your Android app's /res directory, you can only use permitted dir-names. E.g. you can't have a /res/layout-myscreen1 and /res/layout-myscreen2. You also must put your resources in /res, and your code files in packages, so they're at separate places in your project.
You can use Working Sets to group related files together however, but they're quite painful to use IMHO. Check the eclipse docs and tutorials out on them.