Build Android GUI apps with Swift 3.0 via a framework/library

In Swift 3.0 you can build Android apps in Linux but only console apps as
there is no framework to build GUI apps using JNI.
What I propose is to build an initial limited framework coded in C that
calls enough of the Java Android API via JNI to bootstrap the android app
and to create widgets and layouts.A default Androidmanifest.xml file and
some files needed to be generated to make a valid android app.
  The Android API java surface is vast, so this framework needs to be build
over many releases to be useful. Developing a graphical Android app
requires interaction with "Activities" and the package manager and some
widgets like Button and some layouts like "RelativeLayout" and
"LinearLayout".
The result will be the ability to develop GUI Android apps on Linux using
Swift 3.0
Further support for additional APIs will be provided once the basics are
solid..
Who am I: Senior Android mobile developer with more than six years
experience on Android.
Am I able to build Swift 3.0 on Linux: Yes
Any help, suggestions, or ideas are most welcome
Warms regards,
Tony Constantinides

Ok,
Can I take the fact that there no feedback yet on
a) The community is not interested in writing Android apps in Swift
or
b) Wrong forum despite the fact the inventor the Swift programming language
pointed me here,
or
c) This has been tried and failed before.
I sincerely interested in the Swift community thoughts and ideas. I
sincerely want to build this project based on the desires of the Swift
developers community. Let me know what you think about the proposal
and yes, I can present in much more detail.
I took the idea from this page
https://github.com/apple/swift/blob/master/docs/Android.md
Thank you
Sincerely yours,
Tony Constantinides

···

On Wed, Oct 12, 2016 at 5:12 PM, Tony Constantinides < constantinnovationsinc@gmail.com> wrote:

In Swift 3.0 you can build Android apps in Linux but only console apps as
there is no framework to build GUI apps using JNI.
What I propose is to build an initial limited framework coded in C that
calls enough of the Java Android API via JNI to bootstrap the android app
and to create widgets and layouts.A default Androidmanifest.xml file and
some files needed to be generated to make a valid android app.
  The Android API java surface is vast, so this framework needs to be
build over many releases to be useful. Developing a graphical Android app
requires interaction with "Activities" and the package manager and some
widgets like Button and some layouts like "RelativeLayout" and
"LinearLayout".
The result will be the ability to develop GUI Android apps on Linux using
Swift 3.0
Further support for additional APIs will be provided once the basics are
solid..
Who am I: Senior Android mobile developer with more than six years
experience on Android.
Am I able to build Swift 3.0 on Linux: Yes
Any help, suggestions, or ideas are most welcome
Warms regards,
Tony Constantinides

I think it is too soon to tackle this issue.

I think there is room for making adapters for a lightweight GUI toolkit for embedded applications. For example, a Swift adapter for EFL <https://www.enlightenment.org/about-efl> (of Enlightenment) or something like that. But when we talk about Android, we are usually talking about a real Android app that can be a good citizen in Google ecosystem. I don’t think this is feasible right now.

Current Android GUI services is too intertwined with its proprietary runtime and VM and Google is continuing to tie them harder and harder to its Google services API. Unless Google starts treating non-Dalvik-based languages as first class citizens in Android development world, there is no point in trying to make Swift usable as a GUI development language for Android. It is not going to work.

Just my opinion.

···

On Oct 13, 2016, at 2:56 PM, Tony Constantinides via swift-users <swift-users@swift.org> wrote:

Ok,
Can I take the fact that there no feedback yet on
a) The community is not interested in writing Android apps in Swift
or
b) Wrong forum despite the fact the inventor the Swift programming language pointed me here,
or
c) This has been tried and failed before.
I sincerely interested in the Swift community thoughts and ideas. I sincerely want to build this project based on the desires of the Swift developers community. Let me know what you think about the proposal and yes, I can present in much more detail.
I took the idea from this page
https://github.com/apple/swift/blob/master/docs/Android.md
Thank you
Sincerely yours,
Tony Constantinides

On Wed, Oct 12, 2016 at 5:12 PM, Tony Constantinides <constantinnovationsinc@gmail.com <mailto:constantinnovationsinc@gmail.com>> wrote:
In Swift 3.0 you can build Android apps in Linux but only console apps as there is no framework to build GUI apps using JNI.
What I propose is to build an initial limited framework coded in C that calls enough of the Java Android API via JNI to bootstrap the android app and to create widgets and layouts.A default Androidmanifest.xml file and some files needed to be generated to make a valid android app.
  The Android API java surface is vast, so this framework needs to be build over many releases to be useful. Developing a graphical Android app requires interaction with "Activities" and the package manager and some widgets like Button and some layouts like "RelativeLayout" and "LinearLayout".
The result will be the ability to develop GUI Android apps on Linux using Swift 3.0
Further support for additional APIs will be provided once the basics are solid..
Who am I: Senior Android mobile developer with more than six years experience on Android.
Am I able to build Swift 3.0 on Linux: Yes
Any help, suggestions, or ideas are most welcome
Warms regards,
Tony Constantinides

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

Yeah,
I do not disagree with you.
  People who have succeeded have gone down the code generation route.
a) This require them to build a special Swift compiler that generates
Android Java Code from Swift code. They generate a 95% complete Java
Android app and finish it in Android Studio. By doing it that way you avoid
all the runtime issues and the binding issues. The problem is that you have
to mirror the Android SDK on Swift and code Swift like Java. You would have
to update the compiler for every new Java Class you would need to generate
which is not flexible but doable.
b) Other people have tried to port the entire Swift toolchain to Android
but that far too much work and Swift is changing too fast to make that
feasible. Observe the dead projects on GitHub.
c) My first thought was to create a shim that routing messages from the
Swift app to a Java app which translated them to API calls but this has
bootstrapping issues and code maintenance issues.
d) My second thought is to use JNI, as it already been proven that you
can call C code from Swift which in turn can call Android Java code. This
approach require lots of bindings and a bootstrap of the Android runtime
and god knows how many third party libs. The java app also wants to be in
charge and load the JNI bindings as a so file via its LoadLibrary() call.
It might be easier to call Swift from Java rather than the other way round
if the Swift code could be built as a library. Writing JNI glue code does
not excite me.

Since I can already build Swift on Linux and ARM, I do have the ability to
generate an Android runnable app from Swift code. The only issue is that I
am using the Android NDK way of writing Android which provides access to
only the C++ API of Android which is far smaller API surface that the huge
Java API surface and its big runtime. This evolves Swift calling an LVM
module library that contains C code that call the Android NDK API which
bootstrap the NativeActivity class in Android (and the android runtime) and
from there you can access the Camera and multimedia API just not the GUI
widgets.
  This is not too soon to think about as Swift language changes are
supposed to be minimal until Swift 4.0. Of course Google could do the work
for me but I not holding my breath. You can also build Android GUI apps
without every referencing the Google Service API but I do notice that the
Google Service API is being extended because it does not require an Android
OS update to get new features into Android..

···

On Thu, Oct 13, 2016 at 5:20 PM, Hooman Mehr <hooman@mac.com> wrote:

I think it is too soon to tackle this issue.

I think there is room for making adapters for a lightweight GUI toolkit
for embedded applications. For example, a Swift adapter for EFL
<https://www.enlightenment.org/about-efl> (of Enlightenment) or something
like that. But when we talk about Android, we are usually talking about a
real Android app that can be a good citizen in Google ecosystem. I don’t
think this is feasible right now.

Current Android GUI services is too intertwined with its proprietary
runtime and VM and Google is continuing to tie them harder and harder to
its Google services API. Unless Google starts treating non-Dalvik-based
languages as first class citizens in Android development world, there is no
point in trying to make Swift usable as a GUI development language for
Android. It is not going to work.

Just my opinion.

On Oct 13, 2016, at 2:56 PM, Tony Constantinides via swift-users < > swift-users@swift.org> wrote:

Ok,
Can I take the fact that there no feedback yet on
a) The community is not interested in writing Android apps in Swift
or
b) Wrong forum despite the fact the inventor the Swift programming
language pointed me here,
or
c) This has been tried and failed before.
I sincerely interested in the Swift community thoughts and ideas. I
sincerely want to build this project based on the desires of the Swift
developers community. Let me know what you think about the proposal
and yes, I can present in much more detail.
I took the idea from this page
https://github.com/apple/swift/blob/master/docs/Android.md
Thank you
Sincerely yours,
Tony Constantinides

On Wed, Oct 12, 2016 at 5:12 PM, Tony Constantinides < > constantinnovationsinc@gmail.com> wrote:

In Swift 3.0 you can build Android apps in Linux but only console apps as
there is no framework to build GUI apps using JNI.
What I propose is to build an initial limited framework coded in C that
calls enough of the Java Android API via JNI to bootstrap the android app
and to create widgets and layouts.A default Androidmanifest.xml file and
some files needed to be generated to make a valid android app.
  The Android API java surface is vast, so this framework needs to be
build over many releases to be useful. Developing a graphical Android app
requires interaction with "Activities" and the package manager and some
widgets like Button and some layouts like "RelativeLayout" and
"LinearLayout".
The result will be the ability to develop GUI Android apps on Linux
using Swift 3.0
Further support for additional APIs will be provided once the basics are
solid..
Who am I: Senior Android mobile developer with more than six years
experience on Android.
Am I able to build Swift 3.0 on Linux: Yes
Any help, suggestions, or ideas are most welcome
Warms regards,
Tony Constantinides

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

Android N and later may changes a lot, I would use Kotlin which has
similarity to Swift syntax.

Kotlin Lang
https://www.toptal.com/software/kotlin-android-language

Javascript for mobile app for best compatibility.

···

On Fri, Oct 14, 2016 at 9:34 AM, Tony Constantinides via swift-users < swift-users@swift.org> wrote:

Yeah,
I do not disagree with you.
  People who have succeeded have gone down the code generation route.
a) This require them to build a special Swift compiler that generates
Android Java Code from Swift code. They generate a 95% complete Java
Android app and finish it in Android Studio. By doing it that way you avoid
all the runtime issues and the binding issues. The problem is that you have
to mirror the Android SDK on Swift and code Swift like Java. You would have
to update the compiler for every new Java Class you would need to generate
which is not flexible but doable.
b) Other people have tried to port the entire Swift toolchain to Android
but that far too much work and Swift is changing too fast to make that
feasible. Observe the dead projects on GitHub.
c) My first thought was to create a shim that routing messages from the
Swift app to a Java app which translated them to API calls but this has
bootstrapping issues and code maintenance issues.
d) My second thought is to use JNI, as it already been proven that you
can call C code from Swift which in turn can call Android Java code. This
approach require lots of bindings and a bootstrap of the Android runtime
and god knows how many third party libs. The java app also wants to be in
charge and load the JNI bindings as a so file via its LoadLibrary() call.
It might be easier to call Swift from Java rather than the other way round
if the Swift code could be built as a library. Writing JNI glue code does
not excite me.

Since I can already build Swift on Linux and ARM, I do have the ability
to generate an Android runnable app from Swift code. The only issue is that
I am using the Android NDK way of writing Android which provides access to
only the C++ API of Android which is far smaller API surface that the huge
Java API surface and its big runtime. This evolves Swift calling an LVM
module library that contains C code that call the Android NDK API which
bootstrap the NativeActivity class in Android (and the android runtime) and
from there you can access the Camera and multimedia API just not the GUI
widgets.
  This is not too soon to think about as Swift language changes are
supposed to be minimal until Swift 4.0. Of course Google could do the work
for me but I not holding my breath. You can also build Android GUI apps
without every referencing the Google Service API but I do notice that the
Google Service API is being extended because it does not require an Android
OS update to get new features into Android..

On Thu, Oct 13, 2016 at 5:20 PM, Hooman Mehr <hooman@mac.com> wrote:

I think it is too soon to tackle this issue.

I think there is room for making adapters for a lightweight GUI toolkit
for embedded applications. For example, a Swift adapter for EFL
<https://www.enlightenment.org/about-efl> (of Enlightenment) or
something like that. But when we talk about Android, we are usually talking
about a real Android app that can be a good citizen in Google ecosystem. I
don’t think this is feasible right now.

Current Android GUI services is too intertwined with its proprietary
runtime and VM and Google is continuing to tie them harder and harder to
its Google services API. Unless Google starts treating non-Dalvik-based
languages as first class citizens in Android development world, there is no
point in trying to make Swift usable as a GUI development language for
Android. It is not going to work.

Just my opinion.

On Oct 13, 2016, at 2:56 PM, Tony Constantinides via swift-users < >> swift-users@swift.org> wrote:

Ok,
Can I take the fact that there no feedback yet on
a) The community is not interested in writing Android apps in Swift
or
b) Wrong forum despite the fact the inventor the Swift programming
language pointed me here,
or
c) This has been tried and failed before.
I sincerely interested in the Swift community thoughts and ideas. I
sincerely want to build this project based on the desires of the Swift
developers community. Let me know what you think about the proposal
and yes, I can present in much more detail.
I took the idea from this page
https://github.com/apple/swift/blob/master/docs/Android.md
Thank you
Sincerely yours,
Tony Constantinides

On Wed, Oct 12, 2016 at 5:12 PM, Tony Constantinides < >> constantinnovationsinc@gmail.com> wrote:

In Swift 3.0 you can build Android apps in Linux but only console apps
as there is no framework to build GUI apps using JNI.
What I propose is to build an initial limited framework coded in C that
calls enough of the Java Android API via JNI to bootstrap the android app
and to create widgets and layouts.A default Androidmanifest.xml file and
some files needed to be generated to make a valid android app.
  The Android API java surface is vast, so this framework needs to be
build over many releases to be useful. Developing a graphical Android app
requires interaction with "Activities" and the package manager and some
widgets like Button and some layouts like "RelativeLayout" and
"LinearLayout".
The result will be the ability to develop GUI Android apps on Linux
using Swift 3.0
Further support for additional APIs will be provided once the basics are
solid..
Who am I: Senior Android mobile developer with more than six years
experience on Android.
Am I able to build Swift 3.0 on Linux: Yes
Any help, suggestions, or ideas are most welcome
Warms regards,
Tony Constantinides

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

Kotlin does not run on iOS without some custom VM (Robot VM) which would
kill performance. Kotlin is based on Java byte code compatibility so it
really an Android only solution. JavaScript work across platforms but has
limited functionality based on its programming model. Getting a ListView to
scroll with hundreds of items in it is still almost impossible in
Javascript. It also (ReactJS) has to call native code to get anything done
expect its bridge is going to be slower than my native JNI calls. Sure
developers can cop out with Kotlin and JavaScript but both of those
solutions are sub-optimal.

The key is to use a programming language that is support on one platform
(IOS and MacOS) and make it work on another while retaining the ability to
make native calls. Since i can already generate Android ARM code from Swift
on Linux, we just need to ability to call Android 18K API calls to be fully
Android complaint. Since Swift support Clang modules which is basically a C
lib with a module map, I can write JNI calls to the Android Java API via
these modules in C. I would then use the Swift "import xxx" to use these
APIs.

  The key here is to bootstrap Android run time library and not require
developer to relearn 18K API calls. To avoid the Java Native Interface
calls I could go done the custom compiler approach or code generation
approach. By instead of one co debase I would then have two. Anyone else
have any ideas otherwise I get the impression I posting to the wrong
mailing group.

···

On Oct 15, 2016 11:07, "Proyb P" <proyb6@gmail.com> wrote:

Android N and later may changes a lot, I would use Kotlin which has
similarity to Swift syntax.

Kotlin Lang
https://www.toptal.com/software/kotlin-android-language

Javascript for mobile app for best compatibility.

On Fri, Oct 14, 2016 at 9:34 AM, Tony Constantinides via swift-users < > swift-users@swift.org> wrote:

Yeah,
I do not disagree with you.
  People who have succeeded have gone down the code generation route.
a) This require them to build a special Swift compiler that generates
Android Java Code from Swift code. They generate a 95% complete Java
Android app and finish it in Android Studio. By doing it that way you avoid
all the runtime issues and the binding issues. The problem is that you have
to mirror the Android SDK on Swift and code Swift like Java. You would have
to update the compiler for every new Java Class you would need to generate
which is not flexible but doable.
b) Other people have tried to port the entire Swift toolchain to Android
but that far too much work and Swift is changing too fast to make that
feasible. Observe the dead projects on GitHub.
c) My first thought was to create a shim that routing messages from the
Swift app to a Java app which translated them to API calls but this has
bootstrapping issues and code maintenance issues.
d) My second thought is to use JNI, as it already been proven that you
can call C code from Swift which in turn can call Android Java code. This
approach require lots of bindings and a bootstrap of the Android runtime
and god knows how many third party libs. The java app also wants to be in
charge and load the JNI bindings as a so file via its LoadLibrary() call.
It might be easier to call Swift from Java rather than the other way round
if the Swift code could be built as a library. Writing JNI glue code does
not excite me.

Since I can already build Swift on Linux and ARM, I do have the ability
to generate an Android runnable app from Swift code. The only issue is that
I am using the Android NDK way of writing Android which provides access to
only the C++ API of Android which is far smaller API surface that the huge
Java API surface and its big runtime. This evolves Swift calling an LVM
module library that contains C code that call the Android NDK API which
bootstrap the NativeActivity class in Android (and the android runtime) and
from there you can access the Camera and multimedia API just not the GUI
widgets.
  This is not too soon to think about as Swift language changes are
supposed to be minimal until Swift 4.0. Of course Google could do the work
for me but I not holding my breath. You can also build Android GUI apps
without every referencing the Google Service API but I do notice that the
Google Service API is being extended because it does not require an Android
OS update to get new features into Android..

On Thu, Oct 13, 2016 at 5:20 PM, Hooman Mehr <hooman@mac.com> wrote:

I think it is too soon to tackle this issue.

I think there is room for making adapters for a lightweight GUI toolkit
for embedded applications. For example, a Swift adapter for EFL
<https://www.enlightenment.org/about-efl> (of Enlightenment) or
something like that. But when we talk about Android, we are usually talking
about a real Android app that can be a good citizen in Google ecosystem. I
don’t think this is feasible right now.

Current Android GUI services is too intertwined with its proprietary
runtime and VM and Google is continuing to tie them harder and harder to
its Google services API. Unless Google starts treating non-Dalvik-based
languages as first class citizens in Android development world, there is no
point in trying to make Swift usable as a GUI development language for
Android. It is not going to work.

Just my opinion.

On Oct 13, 2016, at 2:56 PM, Tony Constantinides via swift-users < >>> swift-users@swift.org> wrote:

Ok,
Can I take the fact that there no feedback yet on
a) The community is not interested in writing Android apps in Swift
or
b) Wrong forum despite the fact the inventor the Swift programming
language pointed me here,
or
c) This has been tried and failed before.
I sincerely interested in the Swift community thoughts and ideas. I
sincerely want to build this project based on the desires of the Swift
developers community. Let me know what you think about the proposal
and yes, I can present in much more detail.
I took the idea from this page
https://github.com/apple/swift/blob/master/docs/Android.md
Thank you
Sincerely yours,
Tony Constantinides

On Wed, Oct 12, 2016 at 5:12 PM, Tony Constantinides < >>> constantinnovationsinc@gmail.com> wrote:

In Swift 3.0 you can build Android apps in Linux but only console apps
as there is no framework to build GUI apps using JNI.
What I propose is to build an initial limited framework coded in C that
calls enough of the Java Android API via JNI to bootstrap the android app
and to create widgets and layouts.A default Androidmanifest.xml file and
some files needed to be generated to make a valid android app.
  The Android API java surface is vast, so this framework needs to be
build over many releases to be useful. Developing a graphical Android app
requires interaction with "Activities" and the package manager and some
widgets like Button and some layouts like "RelativeLayout" and
"LinearLayout".
The result will be the ability to develop GUI Android apps on Linux
using Swift 3.0
Further support for additional APIs will be provided once the basics
are solid..
Who am I: Senior Android mobile developer with more than six years
experience on Android.
Am I able to build Swift 3.0 on Linux: Yes
Any help, suggestions, or ideas are most welcome
Warms regards,
Tony Constantinides

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

_______________________________________________
swift-users mailing list
swift-users@swift.org
https://lists.swift.org/mailman/listinfo/swift-users

If you mean RoboVM, it claims to use ahead-of-time compilation of Java to native code, so there shouldn’t be much of a performance penalty. (Definitely a size penalty, though!) However, RoboVM appears to have been discontinued.

—Jens

···

On Oct 16, 2016, at 1:35 PM, Tony Constantinides via swift-users <swift-users@swift.org> wrote:

Kotlin does not run on iOS without some custom VM (Robot VM) which would kill performance.

So according to the Swift Community I should adapt Kotlin and not Swift as
my choice for the programming language for a cross-platform GUI framework?
Is that really going to be easier than building a GUI framework for Android
as listed on this page?
https://github.com/apple/swift/blob/master/docs/Android.md

The main technical issues I can think of when building Android Java API
Access is the following:
a) You can only call static Java methods from the NDK Main Thread in Android
b) If I go the Android NDK(C/C++) approach, it provides access to the C++
API of Android but not the Java API of Android. It bootstraps differently
in that you have access to a NativeActivity class but a lot of Java Android
is deriving from an Activity and adding your overrides. I wonder if that
possible doing that with JNI
c) You would not have access to the XML way of declaring an Android GUI but
will have to do everything in code (I have experience in this in Android).
This is not a problem just extra work
d) Since the Java API of Android bootstraps differently you would need to
add libraries to your module maps in Swift so you can bootstrap the Java VM
literally in Android so you have access to the Java Environment via Java
Native Interface.

Anyone else think of how to call Java API from Swift? I was thinking a
bootstrap Java Android skeleton app, which receives an API via a 64 bit
encoded number. The number is converted into a string and passed into a
switch statement where the correct API call is made.
Any fresh ideas?
Sincerely yours,
Tony Constantinides

···

On Mon, Oct 17, 2016 at 9:34 AM, Jens Alfke <jens@mooseyard.com> wrote:

On Oct 16, 2016, at 1:35 PM, Tony Constantinides via swift-users < > swift-users@swift.org> wrote:

Kotlin does not run on iOS without some custom VM (Robot VM) which would
kill performance.

If you mean RoboVM, it claims to use ahead-of-time compilation of Java to
native code, so there shouldn’t be much of a performance penalty.
(Definitely a *size* penalty, though!) However, RoboVM appears to have
been discontinued.

—Jens

I created a Android app in Swift with bindings to Android APIs in Swift (Including UI and Bluetooth), and ported UIKit to Android.

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