Database Users

[Q] Making app compatible with older Android version?

I'm new to the forums and a novice programmer but here's my question:
There's an app I'd like to run on my device for work. Per the play store, the app requires Android 2.3.3 and I'm running 2.2.2. I'm running the most recent version of a custom ROM on an outdated device so can't update my device's build.
I'm wondering if it's possible to tweak the app's source code and repackage it to make it run on my device. I have downloaded the .apk file and tried to install it on my phone and get a parsing error. So with the help of google I have managed to get into the source code using dex2jar and jd-gui. Problem is I don't know much about how apks are written. I found something in the 'accessibilityservice' area that seems to check the android build version, but as far as I can tell that is checking for whether the device is running ICS (if build >= 14) whereas the app is said to be compatible with older builds as well.
Anyway - how complicated would it be to port an app backwards so that I could run it on my phone? You should assume that I'm already in over my head.
Thanks.

petegw42 said:
I'm new to the forums and a novice programmer but here's my question:
There's an app I'd like to run on my device for work. Per the play store, the app requires Android 2.3.3 and I'm running 2.2.2. I'm running the most recent version of a custom ROM on an outdated device so can't update my device's build.
I'm wondering if it's possible to tweak the app's source code and repackage it to make it run on my device. I have downloaded the .apk file and tried to install it on my phone and get a parsing error. So with the help of google I have managed to get into the source code using dex2jar and jd-gui. Problem is I don't know much about how apks are written. I found something in the 'accessibilityservice' area that seems to check the android build version, but as far as I can tell that is checking for whether the device is running ICS (if build >= 14) whereas the app is said to be compatible with older builds as well.
Anyway - how complicated would it be to port an app backwards so that I could run it on my phone? You should assume that I'm already in over my head.
Thanks.
Click to expand...
Click to collapse
A LOT of things changed from pre-2.3 to 2.3 in Android, code-wise. It was a huge upgrade, and a lot of unsupported things were implemented.
It's set to run on 2.3.3 simply because it uses functions that only exist in 2.3.3 and higher.
So to backport it you'd need to get the source code, check what functions require 2.3.3 or higher, edit them to use other functions/write the code yourself. You can't just simply remove the code that checks what version of Android you're running. That won't do a damn thing.
The last part is the near impossible one, because you'd most likely have to write code that goes deep into the Android framework.
If i were you, i'd simply look for another app that can do what you need and doesn't require 2.3.3 or higher. Though there aren't many out there. Most people base their app on 2.3.3 because like 95% or higher use that version (or a higher one).
If you were to dive into this, you'd need extensive knowledge of Android, Java & backporting.
Though i'm not able to help with that, at least the backporting part.

Moonbloom said:
A LOT of things changed from pre-2.3 to 2.3 in Android, code-wise. It was a huge upgrade, and a lot of unsupported things were implemented.
It's set to run on 2.3.3 simply because it uses functions that only exist in 2.3.3 and higher.
So to backport it you'd need to get the source code, check what functions require 2.3.3 or higher, edit them to use other functions/write the code yourself. You can't just simply remove the code that checks what version of Android you're running. That won't do a damn thing.
The last part is the near impossible one, because you'd most likely have to write code that goes deep into the Android framework.
If i were you, i'd simply look for another app that can do what you need and doesn't require 2.3.3 or higher. Though there aren't many out there. Most people base their app on 2.3.3 because like 95% or higher use that version (or a higher one).
If you were to dive into this, you'd need extensive knowledge of Android, Java & backporting.
Though i'm not able to help with that, at least the backporting part.
Click to expand...
Click to collapse
Thanks for the very helpful information. I will definitely not be attempting this.
Most likely will be getting a newer phone in a few months when I'm due for an upgrade so it'll be a moot point. Until then, I'll get by.

[Q] OpenFileChooser issue - Android webview app

Hi,
I was looking everywhere but couldnt find answer!
Issue
Since api 21, OpenFileChooser into android app webview has changed to OnShowFileChooser. This is causing upload button <input type="file"> to do nothing on click. From there i could find a way to make it work, but i couldnt make it compatible on lower version than 5.0 lollipop
Is there anybody that know a way to make the code compatible with all android version api 8 to 21 thanks!

[Q] setAlpha() in Android Lollipop

Hi there!
I tested my app on Android Lollipop, and I noticed that setAlpha(int value) is not working...
I saw on the Android Reference that setalpha(int) is for 11 below API, and setAlpha(float) for higher APIs.
I tested the app on Android 4.0 (API 14) and it works perfectly... But when I tested on Lollipop (5.01, API 21), the setAlpha doesn´t work :S
What Can I do to solve this porblem?

set android os version (current api level = 17 )

hi newbie here
I have just setup kitchen and I am trying make my first custom rom from G900FXXU1BOJ1_VDI for Galaxy s5 SM_G900F
kitchen is asking to set current api level which is saying is level 17 (Android 4.2.2)
this rom G900FXXU1BOJ1 is for Android 5.0 which is api 21,
Android 5.1 is api 22 and Android 6.0 is api 23,
so my question
is there any point in setting the api level higher than 21
thanks

Yes it does
I noticed that api level also indicate support for apps
I wanted to install stock google phone app right now and thought only arch and dpi are important but seems like as well as api
So all those three will give factors to what apps are your phone's gonna actually support (what version, what etc)
Well that's what I think tho it's better to research still cuz right now im actually researching for it as well

klambo said:
hi newbie here. I have just setup kitchen and I am trying make my first custom rom from G900FXXU1BOJ1_VDI for Galaxy s5 SM_G900F....
Click to expand...
Click to collapse
TheRedAndroid said:
I noticed that api level also indicate support for apps....
Click to expand...
Click to collapse
You had responded to a thread that's around 3 years old but, I hope that the following information is helpful to you and others as well.
Though i've never built a ROM before but, here's a list of different threads for building a Custom ROM where you should be able to obtain some member guidance within one of them as well.
https://forum.xda-developers.com/showthread.php?t=3779833
https://forum.xda-developers.com/showthread.php?t=2073775
https://forum.xda-developers.com/showthread.php?t=3803044
https://forum.xda-developers.com/showthread.php?t=2861778
https://forum.xda-developers.com/showthread.php?t=2814763
https://forum.xda-developers.com/showthread.php?t=2597220
https://forum.xda-developers.com/showthread.php?t=1272270
https://forum.xda-developers.com/showthread.php?t=3503018
https://forum.xda-developers.com/showthread.php?t=3179331
https://forum.xda-developers.com/showthread.php?t=2223690
https://forum.xda-developers.com/showthread.php?t=3406216
https://forum.xda-developers.com/showthread.php?t=2695356
https://forum.xda-developers.com/showthread.php?t=2069130
This is only a handful on the forum but, I believe that this will give you a good start... LMAO!!!
Good Luck!
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I DO NOT provide support via PM unless asked/requested by myself. PLEASE keep it in the threads where everyone can share.

Idea for fix NFC rom 6.0.1 Note 3

Hi all,i wanted to ask all developers 6.0.1 ROM for Note 3, if exstracting all files of the NFC from a stock firmware and put them in your rom you can fix this problem,this is just my idea, since no i'm a developer.
Thank you!!!

If it were that simple, someone would have done it already.

Last OFFICIAL Note 3 ROM Is Lollipop 5.0. That is Android API level 21.
Marshmallow Android 6.01 is API level 23.
It is not possible (easy?) to mix API level 21 and API level 23 system apps.
Thus, unless somebody gets Android sources from Samsung for the NFC drivers and compiles them to API level 23 (Android 6.0.1) it is unlikely that NFC will work on Note 3 under Marshmallow 6.0.1 custom ROMs.
There is a possibility that the people tweaking the CM ROMs (6.0.x API Level 23) will get NFC working on Note 3. If they do, that source might be usable for Custom TouchWiz based Note 3 ROMs (or then not).
But it requires more than just copying old system files from previous API level on top of a new ROM.

That seems logical. But what if we take the NFC part of the NOTE 5 or S7? Maybe not for the entire NFC stuff, but maybe as a base of work?