Hi Mark

hello, Susheel!

how can I help you today?

(BTW, happy Back to the Future Day!)

I am currently trying to build this project I have cloned from my github to Android Studio...https://github.com/susheel17/android-s...

Thank you :)

This project has native class written in C

So I followed all guidelines to build NDK

I even included pre-built .so files

But i have an error 'Error:Cause: com.android.build.gradle.managed.AndroidConfig_Impl'

there should be more to the error message in your Gradle Console than that, I would think

I promise that's all there is: obviously there is the gradle project refresh failed

then there's not a lot I can tell you

hmm

this project is as old as the hills, though

Yeah haha!

I removed the link to the so files from my build.gradle...it allows me to run the app on the device...but when I use the core functionality of the app which is in native code, the app crashes with this message

cannot locate symbol "tcgetattr" referenced by "libserial_port.so"...

right, that would indicate that the .so files cannot be found, which would make sense

have you recompiled the project's NDK code yourself?

yes i had to remove some warnings by annotating but yes i did

do you mean build or recompile?

sorry

um, well, that'd amount to the same thing in this case

oh ok...in that case I was able to build the project and run the app on the device

well, if that worked, what's the problem?

but when I click a button that opens a serial port that's what use the native code and it crashes with the message I referenced earlier

so its not able to find the .so files

but I put them in a libs folder under project/app/

because I had pre-built .so files from my eclipse project for the same code

if your project is set up properly, you shouldn't need to do anything -- the build process will put them in the right spot for you

So .so files are generated if my project is set up properly?

yes

first, I would recommend having this stuff be a separate library module, rather than trying to merge it in with your main app code

right

then, take a look at projects with the NDK setup in there, such as https://github.com/commonsguy/cwac-anddown

I use the ndk closure in build.gradle for the library module

and, since this project is still somewhat Eclipse-friendly, I fix up the main sourceset to point to where the JNI files are

from there, it builds, runs, puts the binaries in the right spot, and it all gets picked up by the demo/ app

so I put this block in my build.gradle file to tell the ndk location

I haven't needed ldLibs yet, so I can't tell you if that's right or wrong

(I do very little C/C++ work personally)

that is just because there are log comments in the c file

oh

Can I request some video chat time with you asap to help me on this project? All I need is to be able to build and run the core serial port functionality.

to be honest, it is *very* unlikely to be worth your while

oh!

again, outside of this one project, and a book demo or two, I do nothing with the NDK

got it

so coming back to this error 'cannot locate symbol "tcgetattr" referenced by "libserial_port.so"...

you think there is something wrong with the way I am linking my jni files?

possibly

gotcha

either the .so files are not making it into the APK, or they are not being loaded properly at runtime

have you manually inspected your APK file to see if your .so files seem to be in there?

and the cause is most likely the jni files?

not yet

I can't give you a "most likely" on anything regarding the NDK

again, I very rarely use it

got it

part of the reason I am pointing you to AndDown is that it is my best example of NDK code, that I am familiar with and that works

I will read that right away...

so, for example, you could compare your APK to the AndDown demo app APK

and see if the .so files seem to be in equivalent spots

please can you tell me where the apk is generated in Android Studio?

app/build/outputs/apk, IIRC

awesome thanks

where app/ is your application module

right

if the .so files are in the right spot in your APK, try running the app again, and see if there are any LogCat messages in the milliseconds before your crash that complain about linking erorrs

er, errors

in that case, perhaps something is up with ldLibs, which AndDown is not using

and once you get past that, I'm largely out of suggestions

Thank you very much for all your help

sorry I didn't have a more conclusive answer for you

no problem. you've given me a lot of pointers. Thank you Mark!

but I have one more question about examining the apk...how would I be able to view the contents of an apk?

it's just a ZIP file

oh!

my Ubuntu environment just lets me double-click on it to view the contents; I forget if I set that up myself or Ubuntu just recognizes the file extension

I am developing on a mac

there's probably no feature like that for MacOS

I would hope OS X lets you teach it what to do for unrecognized file extensions

regardless, if nothing else, use the commandline unzip utility

right

thanks

I have one other question for you

OK

I have ADT already running on my other machine

I was wondering if I installed gradle plugin, would I be able to import all gradle android libraries just by including the dependencies?

well, ADT has nothing to do with Gradle

unless there have been some changes on the Eclipse/ADT side that I am unaware of

now, you can build an Eclipse/ADT project with Gradle, but it takes a build.gradle file that maps the directory structure properly

ironically, those AndDown projects demonstrate this, as I have not yet cut them over to be Android Studio-centric

right...is that process covered in the book anywhere?

oh

I think I may still have material on that

though I am slowly de-Eclipse-ing the book

cool

I'd just look at the sourcesets closure in one of those projects and copy it over

right

but I was wondering if there is tutorial to install the gradle plugin for ADT in your book but I guess it is easy to look for one on the web

I am not aware that a Gradle plugin for ADT even exists

Eclipse's Andmore project will eventually take up the mantle of Eclipse-based Android development

but I haven't been tuned into that for a while

so I do not know its status

oh

and with Google dropping Eclipse support at the end of the year, I am counselling everybody to have a plan, pronto

if Andmore is ready, move to it

right

otherwise, get over to Android Studio

right

So did you suggest me to download your anddown project, import it to AS and build it and examine the apk?

yes

earlier when we were talking about comparing apk contents

cool

question on a separate subject....does the book cover transitions apis or any of the new animations apis added in lollipop like circular reveal etc?

no and no

hmm

someday, perhaps, but not high on my list at the moment

and that's a wrap for today's chat

the next one is tomorrow at 9am US Eastern

Thank you for all your help

have a good night!

this transcript will go up on https://commonsware.com/office-hours/ shortly

have a pleasant day!