Python for Android

http://python-for-android.readthedocs.org/

by fabriceleal • 13 years ago

109 74 13 years ago

python-for-android.readthedocs.org

dylangs10304• 13 years ago

I don't use Android devices, so I wouldn't know, but is this the first instance of mobile Python on Android OS?

Jailbroken iPhones have had this capability for years...not to say iOS is better, just that I'd expected this would happen...sooner?

That said, the Python distro on iOS is only 2.6-ish, not even 2.7, and there's no 3.x release there. It's not very useful but I guess I did use it a lot for learning back then.

MatthewPhillips• 13 years ago

Jython won't simply run on Davlik unmodified. Davlik is a brand new VM target for language designers, and Google hasn't put much effort into making it easy for other languages to run on it.

gizmo6862• 13 years ago

Isn't there a tool that translates Java bytecode into Davlik byte-code (dx I think). Even if not, we have functioning decompilers to go from Java byte-code into Java source-code, and a well maintained toolchain to go from Java-source code to Dalvik byte-code.

In fact, you don't even need a Java decompiler to do this. All you need is a backwords Java compiler. That is, one that treats bytecode as a source languages and compiles down to Java. This is a much easier process because (ignoring things like Enums) you don't need to try and figure out what the original code is, and instead can just do a naive decompile with optimization passes.

fabriceleal• 13 years ago

is this the first instance of mobile Python on Android OS?

Honestly, I have no idea. But I'm aware that there are multiple efforts to bring "sane" languages (such as C#, by Xamarin) to Android, others than Java.

Jailbroken iPhones have had this capability for years

I had no idea about this one, but I don't follow iOS development either.

I'd expected this would happen...sooner?

I agree with you, but I believe this sort of thing should be backed by Apple (iOS) or Google (Android) themselves.

[EDIT]: formatting

dylangs10304• 13 years ago

Well, I hope it's being done securely. I don't know much about the particulars of Android's iOS, but having a low-level language with access to the whole OS (which is what a real user would want for mobile programming, really) could be dangerous for native security.

On the other hand, if Google or Apple backed a high-level scripting language like Python, that could also lead to security concerns, but I would feel safer with that than something like C on my mobile device.

myko• 13 years ago

Python has been on Android for a long time. The first instances I know of is SL4A: https://code.google.com/p/android-scripting/

Kivy for Android has been around awhile as well.

knappador2• 13 years ago

Kivy developers are the primary movers behind Python for Android. Typically we are using Cython so that a great deal of the application is actually running in C without the Python runtime eating up overhead. This leaves a budget of about a million function calls per second, or roughly 10,000 per frame, as most of the overhead in the UI thread is eaten up in expensive function stack frame in the event system, passing around events that call callbacks that call callbacks that call callbacks...

It remains to be seen if we can adopt a concurrent model for some aspects of the main application thread(s). Going concurrent almost surely means more Cython and more speed. I'm interested if anyone has any ideas about using CPython to reduce the cost of certain nearly-always-performed functions to grease the event system. Not that it's slow, but fast is always better =)

http://kivy.org/#home

dagw• 13 years ago

Nope, you've been able to run python scripts on your python phone for years. What this seems to do is make it easy to package together an app written in python into an independent package that you can install just like any other android app

pudquick• 13 years ago

Jailbroken iPhones have had this capability for years

As have non-jailbroken ones. I have Python for iOS and Pythonista (my preferred favorite) from the App Store. Python for iOS even comes in a 3.2 flavor.

wyrag• 13 years ago

http://qpython.com/ has been around for a while.

limmeau• 13 years ago

Compare this with the late PyS60, where you installed a little SIS on your phone, 2MB or so, and could then run simple Python scripts. Forwarding all incoming SMSs to another phone number was a six-liner or so.

I've never used it to build big apps, only toyed around with examples, but then again, it wasn't made for the big applications, rather for small ad-hoc scripts.

Kind of Eclipse plugins vs Emacs scripts.

aswanson2• 13 years ago

A bigger question on my mind has been why would a shop as smart as Google not have started out with a sane language like python in the first place instead of foisting this java idiocy on another generation of devs.

druiid2• 13 years ago

I've always wondered this as well. I mean, Google loves Python as evidenced by App Engine, how many of their internal/external tools use Python and other projects I'm forgetting. Basically I would have at least expected it as a built-in option to use (kind of like how Windows Phone 8 has a higher-level and lower-level way of accessing the phone).

pekk• 13 years ago

App Engine has, if anything, better support for Java than Python.

crncosta• 13 years ago

We will never know.

I guess because Python is not statically typed. Most of the efforts they have been supporting (golang, dartlang...) are evidence of they prefer to have Static type-checking around.

nly2• 13 years ago

Java has a granular, stable and simple byte code, Python does not. Java is amenable to static analysis, mainline Python isn't. Dynamic typing means more runtime, burns more battery.

Java also allowed them to leverage a mature and highly optimized frontend. Back in 2008, Psyco/PyPy was there... but fairly wet. Until recently(?) the primary JIT back-end for PyPy was, in fact, still the JVM.

Lexarius2• 13 years ago

Until recently(?) the primary JIT back-end for PyPy was, in fact, still the JVM.

This sounds false. The PyPy Features page does mention that PyPy will run on the JVM, but that it is incomplete there, and in particular they don't have their JIT ported to it yet. Do you have any source on that?

woadwarrior012• 13 years ago

I generally agree with everything you're saying. But as a counterpoint, Dynamic typing doesn't necessarily have to translate to more battery consumption. Objective-C is pretty close to Python when it comes to dynamic typing (also similar in ref-counting for memory management).

jnbiche7• 13 years ago

"Until recently(?) the primary JIT back-end for PyPy was, in fact, still the JVM."

That's not true -- PyPy had an experimental JVM backend early-in, but the first and flagship backend has always been the RPython one.

tvon• 13 years ago

I think this decision was made by Android Inc. before Google purchased them.

gw• 13 years ago

By providing a true API-compatible JVM implementation, they did the opposite of "foisting" -- they provided a way for you to run any JVM-compatible language you want. That, after all, is why we can run Clojure, Scala, and what-have-you as first-class languages on Android with access to all the same APIs as Java.

It is true, of course, that they chose Java as the default language for Android development. I imagine this is because dynamic languages were not always practical on early smartphone hardware, and because there was already a large ecosystem around Java from which they could draw.

voidlogic6• 13 years ago

Google should use Go for Android... Cleaner than Java, faster than Java (on Dalvik).

I can imagine how slow Python on ARM Android is.... and people complain about Java code being slow on Android... I would put money on JS/V8 being faster than Python on Android too.

The following comparison is JVM vs Python, so its really pretty far off the scenario we are discussing, but consider it shows almost up to two orders of magnitude difference..

http://benchmarksgame.alioth.debian.org/u64q/benchmark.php?t...

Sanddancer• 13 years ago

Non-portable. While android primarily runs on ARM boxes, the same APKs, barring any native code libraries, will run on x86 devices running android, MIPS devices, etc.

aswanson2• 13 years ago

Its not clear if the python code was compiled on their benchmarks. That might close the gap.

jnbiche7• 13 years ago

It would be great if Go could be used as a reasonable alternative to Java on Android. Or Clojure. Or Python. Or Lua.

You can already use all of these on Android, but any kind of visual programming is a pain in the ass since you have to do Java interop, and start-up is slow because of the apk unpackaging requirements.

rdtsc2• 13 years ago

Guido was working at Google and he (I understand) try to "fix" the problem. He was told to back off and when asked about it during one of the PyCons the reply was "it was political" not technical.

Moreover it wasn't just that he answered but also how he answered. One could tell he was upset by it, you could hear it in his voice.

staffordrj• 13 years ago

Can you pull up any sources for that?

sgarman• 13 years ago

Even more interesting is what the Android guys had to say about getting newer versions of Java. The tone is very suspect and it almost sounds like they are considering another language. Perhaps that's just me reading into it.

Source: http://www.youtube.com/watch?feature=player_detailpage&v=A5O...

http://www.youtube.com/watch?feature=player_detailpage&v=A5O...

toyg• 13 years ago

Check wikipedia: Android was bought by Google, not created. Also, a critical element of its success was adoption by partners: in this context, preferring Java (very much the "enterprise language") over Python (hackish open-source language with minuscule enterprise presence) was a no-brainer -- hence the "it's political" answer Guido himself got from the upper echelons.

As a python-aficionado, I stopped kidding myself a few years ago: Python will never be mainstream in the way Java or C# are, the number of people working with it will always be small, unless something dramatic happens at the commercial level. It's like Linux on the desktop: the masses are simply elsewhere.

sentenza• 13 years ago

Im saddened by this. But on the other hand, our good friend Oracle is trying to change it by trying to motivate developers to search for a non-Java language.

simonh• 13 years ago

Trust me, Python is doing very well at Enterprise scale. Here's a taster of what it's about in the below links, which are public information, but the Quartz platform is huge. I wish I was at liberty to discuss it in more depth. If you're keen on Python and willing to work hard, it's worth considering Bank of America Merrill Lynch.

https://us.pycon.org/2013/schedule/presentation/155/

http://careers.bankofamerica.com/JobDetails.aspx?SearchPage=...

mtgx2• 13 years ago

I think they answered that question, and you can probably find it with a Google search - but the reason was this: Python was too slow, especially for the time, which I think is already an uncontested fact.

But for the future? Yeah, I can only hope Google is working on switching Android to Go in a few years. It doesn't even have to be an abrupt change - which definitely won't be - they're not insane. But they can add the language in the NDK or something, and then just promote it to developers as the main language they should be using when making new Android apps.

bpodgursky• 13 years ago

How the hell does drivel like this get upvoted?

zmmmmm2• 13 years ago

Just having gone through about 18 steps to install Python 2.7 on my server because we have code that only runs in 2.7, while most of the operating system only works with 2.6 and breaks with 2.7, and seeing all the backwards compatibility cluster fuck that is Python3k, I think anybody would be crazy to base an operating system like Android on Python.

You can't have backwards compatibility and your progressive "keep language simple and clean by dropping features" at the same time.

dman• 13 years ago

Whis OS is this?

knappador2• 13 years ago

virtualenv is your friend

daGrevis3• 13 years ago

This is really cool!

I'm interested in creating daemons that, for example, forwards SMSes to my email and records made voice calls. Is API good enough to do that?

jnbiche7• 13 years ago

Yes. Daemons are the one implementation where Python's longish start-up time on Android won't make any difference (we're talking a few seconds here, versus under a second for native Android apps, just to be clear). If anything you need is missing from the API, you can use Pyjynius to do easy Java interop.

Another options for this kind of app is SL4A. They have a very complete Android API, but it's a bit harder to hack and not as well documented.

If you want to package an APK, I think this project (Kivy's Python for Android) is probably a slightly better option. You can package APKs with SL4A, but it's a bit trickier. Python for Android even provides a virtual box image of Ubuntu (or Debian, I don't remember) for building APKs, with all the dependencies included, ready to go.

daGrevis3• 13 years ago

So I'm good to go. A pretty big challenge for me, but I will handle it at some weekend for sure! :)

Python for Android

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