Kivy: Cross-Platform Python Framework for UI Development

by ve55 • 6 years ago

177 55 6 years ago

Kivy is awesome considering what it,s trying to do. As ambitious as flutter but without corporate support. Unfortunately the project is quite under-resourced, can anyone help?

For example, stick to the basics and it works well. But do something off the beaten track like write a background service for Android and hit a bug and you're completely on your own, even if you offer to pay a core dev. I once hit another bug where Unicode couldn't be used in .kv files, was a one line fix but there were 70 unread pull requests and more even more issues untouched. Two or three heros try to help on the mailing list. I gave up but would like to try one more time with 2.0.

mzakharo12• 6 years ago

What problems did you have with android services? Have been using them without issues (sticky services work well enough), and with python machine learning/scikit-learn, scipy,numpy, pandas, opencv this framework is one of a kind for rapid moibile development if you are doing any kind of edge data processing.

mixmastamyk2• 6 years ago

Giant tracebacks that no one could help with. I'll try again soon with 2.0.

Apocryphon8• 6 years ago

It's quite fascinating to read about mobile crossplatform projects beyond React Native/Flutter/Xamarin and the old Cordova/PhoneGap and Appcelerator Titanium efforts. There's a surprising amount of them out there- Kivy isn't even the only one in Python, there's also Beeware (https://www.youtube.com/watch?v=qaPzlIJ57dk) and PyMob.

The question is, who actually uses these projects? The people developing them? Hobbyists? Language diehards? If you're a large company that just needs LOB apps, one would assume one of the aforementioned projects (or Delphi) would be sufficient. Who uses NativeScript, Ionic, QT on mobile, or obscure stuff like Sencha, Alibaba's Weex or Codename One?

RubyMotion at least has one famous app:

http://www.rubymotion.com/news/2014/04/08/rubymotion-success...

tmpz22• 6 years ago

Great UI has diminishing returns that, for most orgs, are not worth the talent and effort it takes to create them. For that reason investment in these frameworks, or new frameworks at all, is discouraged. Web based approaches have completely supplanted native || crossplatform frameworks because its good enough and established enough to diminish the many development liabilities that other frameworks pose.

mzakharo12• 6 years ago

Not everyone is trying to display a widget, with data from a remote database. If you work with local/edge data, then having access to numpy/pandas/scikit-learn/pytorch can be quite handy

Apocryphon8• 6 years ago

But the point of cross-platform frameworks is for non-tech or non-mobile focused companies to quickly churn out LOB apps with whatever developers they have on hand. (There was even one for PHP - KikApp - which appears to be dead.) So in theory, ignoring great UI/UX in favor of quick development time would drive investment in and adoption of some of these frameworks.

Your point on web based approaches also doesn't seem to match reality yet as PWA are still the once and future destiny of mobile apps, much like \(currentYear) is the year of Linux on the desktop. afaik, it would seem like most mobile apps are still primarily native, and if crossplatform, possibly React Native or Xamarin, with some older ones using Cordova/PhoneGap/Titanium. Web based approaches are far from replacing native and cross-platform; most companies that support mobile web also have their own apps.

inclemnet3• 6 years ago

The question is, who actually uses these projects? The people developing them? Hobbyists? Language diehards?

This is an interesting question, and one that (as Kivy developers) we wonder about ourselves. Others may have different perspectives, but mine is:

* Kivy is very much community built and community driven, it has no serious financial backing (though we are grateful for the donations we do get!) and a fairly small developer pool.

* Most of the commercial use of Kivy that I'm aware of is small companies using it for specific reasons that happen to make sense for them, usually involving some technical reason such as the combination of Python and a flexible drawing toolkit fitting both their dev interests and product requirements. I don't think there is a lot of commercial use, but e.g. one of the Kivy founders has been using Kivy commercially for many years in a variety of interesting projects.

* Kivy is not mobile-only or even mobile-focused, and the commercial usage reflects that. This is worth noting because people often think it was invented for mobile: it wasn't, it was invented to be very flexible, and this happened to make it mobile-ready.

* Most use of Kivy is probably from Python hobbyists, and may well be more weighted towards mobile since that's the most obvious standout feature as a Python gui toolkit (although not the only one).

I've been involved with Kivy for a long time, but never commercially - I got into it for fun while looking to make an app and strugging with an android development tutorial (turns out the instructions were just wrong for Linux...), and stayed with it for also fun. I'm most interested in the general principle that app development ought to be simple and easy for a wide range of tasks, and that in pursuit of this goal it does not have to be perfect. I like the idea that e.g. someone who has programmed a simple game or visualisation should be able to easily share it with their friends, on any platform including mobile. This is just my perspective of course, others do use it for other things.

I have a couple of my own apps that I think emphasise this perspective. Lazy Baduk (https://play.google.com/store/apps/details?id=net.inclem.laz...) is a Go analysis tool that bundles a superhuman AI: I threw it together in a weekend using some existing Python code I had lying around, because there was no Android app currently supporting the functionality I wanted. If I couldn't do that with Python, the app simply wouldn't exist. ColourBlind (https://play.google.com/store/apps/details?id=net.inclem.col...) runs the camera feed through a basic colour blindness simulation filter, I made this one just because I wanted to see what it was like and all the existing apps I could find were rubbish (in my opinion!). Even with the limitations of Python, I like mine much better than them.

Apocryphon8• 6 years ago

Very comprehensive answer, thank you! I'm glad to hear that Kivy has larger aspirations than simply being a mobile focused cross-platform solution, and that it's got enough of a community to sustain its efforts. Cool also that it's able to leverage Python tools that the native mobile apps aren't able to hook into. It sounds like Kivy does have a small community of avid Pythonistas.

cmrdsprklpny2• 6 years ago

I'm a hobbyist and I've been looking into these kinds of projects for a while. From my (limited) experience, the easiest way to go for a lot of cases is just to use a cross-platform game engine's UI capabilities, but there's some other interesting not-well-known stuff like HaxeUI and LambdaNative.

Apocryphon8• 6 years ago

use a cross-platform game engine's UI capabilities

Have you seen any examples, either production apps or tutorials doing so? Ironically, I've considered building a heavily menu-driven game in Flutter rather than using Unity, and seen an example of such:

https://www.reddit.com/r/FlutterDev/comments/iit6cf/i_made_a...

hardwaresofton7• 6 years ago

Nativescript is fantastic -- I maintain that it's better than React Native because React Native lacks a native JS->platform translation layer and React-land is crazy sauce, and can't really be compared with Flutter (because of how Flutter works), but I still think it's better there even because I'd pick Typescript over Dart, and I don't have to commit so hard to the ecosystem.

I've used Nativescript in production and it was wonderfully productive. I think it's biggest weak point is suffering from lack of recent support/ecosystem that hype usually brings.

The ability to use your frontend framework of choice (Angular, Vue, Svelte, Vanilla JS) is awesome, and I think can be incredibly productive for businesses (turn your frontend devs into mobile devs).

Apocryphon8• 6 years ago

Progress is no Facebook/Google/Microsoft, but it's good that there's someone actively working on the framework. Shame they haven't tried to market NativeScript as an alternative to React Native.

At least it's better known that other random enterprise cross-platform solutions that seem to exist only on SEO-optimized listicles of cross-platform solutions such as Codename One, RhoMobile, Kony, Framework7, - e.g. https://www.way2smile.ae/blog/cross-platform-mobile-app-deve... (Again, what companies are actually building apps with these things?)

bikeshaving• 6 years ago

The one thing I wonder, can you explain why the Vue wrapper around React Native (https://github.com/GeekyAnts/vue-native-core/stargazers) seems to be more popular than Vue NativeScript (https://github.com/nativescript-vue/nativescript-vue/stargaz...)? I’m confused by why Vue developers of all people would use a Facebook/React stack for native development, so I assumed there had to be some advantage to using React Native.

baybal23• 6 years ago

We used Nativescript in production, and it is unending train wreck.

I advise everybody to avoid Nativescript for as long they self-qualify their project as anything serious.

The ecosystem, and upstream looks really much like the Wordpress plugin world, and is grossly unprofessional.

On the technical side, you will be always struggling with OOM, I/O performance, and the fact that you will be spending MORE time on native code for both Android, and Ios than if you did them separately.

arcturus172• 6 years ago

React-land is crazy sauce

In what sense?

I develop my front ends primarily in React, and other than hooks - which a lot of people have adopted anyway, and only extended the lib - the API seems very stable. The 3rd party library ecosystem may be wild because React is superpopular and people are publishing npm packages with half-baked solutions of dubious utility, but there's always a good library or two for 95% of tasks (good: regularly maintainted, fully-featured, well-documented, tested, typed, etc.).

I don't have any experience with RN so I don't know how things are there, but your comment seems to be about the React ecosystem at large and doesn't correspond to my experience at all.

craftinator• 6 years ago

I've been using Kivy for internal business programs for 2 years. There are some quirks and limitations, but IMO no more than you get with any other mobile stack. The big differences are that it bundles python packages with it, meaning you have access to hundreds of thousands of libraries via pip, and the design and iteration time are ridiculously low.

The downsides of Kivy are also the downsides of python; there is almost no design enforcement, no typing; if you want to do something stupid and dangerous, you're free to do so with no warnings, and you may not know it's stupid and dangerous. These are usually made up for by the large amount of time you'll have for testing, since you won't spend all the time you normally would fighting the IDE, toolchain, compiler, etc.

The part I like most about Kivy is that it's cross platform, android, ios, windows, Linux, mac, with almost no changes other than OS semantics like paths. I've built 5 large projects this year with it, mostly for custom CNC and motion control applications.

spinningD20• 6 years ago

Ever since I discovered Kivy in 2013, it has had a special place in my heart, and because I know my way around it, I've used it for many smaller projects, and one non-trivial game project WIP: https://www.youtube.com/watch?v=m06AH7MN0i4

Graphically, my game is mostly straight-forward, but being a strategy game, the complexity is behind the curtains in the AI, pathfinding and other game mechanics. I am very thankful to continue using my mastery of Python in this endeavor, and even though it doesn't provide game development conveniences out of the box (so it took time to get started, compared to say, Godot), it allowed me to utilize - and build on - my experience in the language. Doing this allows me to control the learning curve, especially when it comes to learning about OpenGL, and how graphics work underneath in general.

Don't get me wrong, depending on what you're looking to do, Kivy can have a stronger learning curve in itself, especially if you're doing this sort of thing for the first time (app development, specifically, but of course game development too). It took me until around 2016 - after playing with Kivy on and off - to become completely comfortable with all of its concepts. Aside from learning to profile and troubleshoot some graphics performance issues (largely my own fault, in my implementation), Kivy has been reliable and, like a well-designed door, I rarely consciously note that I am using it!

Outside of games, as I mentioned, I have also used Kivy for internal tools professionally. One was for (visually, analog curves) creating simulated plastic injection molding sensor signals, in order to create and provide data sets for QA Automation. The other was for a specialized AV company's (internal) usage as a job/bid/information management app. Another project required the ability to flip, pan and zoom images for a 3d mirror viewer hardware set. And, here in 2020 I used it to train non-automation non-coding QA personnel into making their own mobile apps, learn about event handling, and to get a glimpse into what a developer might be considering or thinking as they build software.

I've always been bewildered at why Kivy doesn't (seem to) garner more public attention. For what it aims to provide, it hits the mark quite well. I enjoy using Python the most, so I prefer to use it for most of my work, personal and professional. In that way, Kivy has allowed me to progress towards mastery of Python, without having to spend that effort on other tech stacks. (Having said that, I have experience outside of Python, just to be clear, it's not out of necessity.) As others I'm sure, I have a life outside of my job and side game project, so I have intentionally chosen what to invest my time in learning.

This turned into a bit of a ramble. Anyway. For me, it's a great fit, and I'm thankful that it exists, and people continue to build and refine it. I get to keep writing Python, and use it in more ways and places because Kivy exists.

ako• 6 years ago

I use it for a hobby project: a weather station running on raspberry pi and touch screen. Allows me to write it in python, and display charts and metrics without running the entire X11 stack.

Seemed like the simplest and most productive stack to build something like this. Has good support for postgres to get the data efficiently, charting and touch input.

bartvk• 6 years ago

Kivy is used in the embedded world, for example by the ECR-1 and GR-1 synthesizers: https://www.tastychips.nl/

epse2• 6 years ago

Kivy has been around for a surprisingly long time and has been fairly widely used in industrial software. I used to work for a company that made kivy-based automation software.

didymospl• 6 years ago

I'm not sure about the current state of affairs but a few years ago Ionic used to be a default choice for cross-platform apps among Angular devs. And Angular itself was probably more popular then React in corporate world back then.

rossdavidh2• 6 years ago

1) I have toyed with Kivy, but found it not easy to use. It was a few years ago.

2) I prefer tkinter, a python wrapper for tk.

3) In regards to whether or not anyone still needs this, consider that tkinter search traffic bottomed out in June 2012, and has been rising ever since: https://trends.google.com/trends/explore?date=all&geo=US&q=t...

tartakovsky2• 6 years ago

So, I’m not sure whether the website was made using the product, but the homepage renders overlapping text on Chrome for IPhone 11 with IOS 14

rossdavidh2• 6 years ago

Kivy is not a web framework, it's a library for making native desktop (or etc.) applications.

inclemnet3• 6 years ago

As has already been said, Kivy isn't a web framework, but we're well aware the website isn't great. Unfortunately it hasn't had much love for a long time, especially as it's quite a task to seriously change it and we're both under-resourced and Python-oriented. We've been talking about various options for a long time. It's possible we might make some moves now as Kivy 2.0 was just recently released, which was a major update taking up a lot of focus.

solarkraft2• 6 years ago

From a marketing protective it may have made sense to revamp the website before launching 2.0 since you could've made a lot of better first impressions.

That said I don't think it's that bad, but the styling could be nicer.

tartakovsky2• 6 years ago

Thanks for clarifying. Good to understand I’ll take a closer look at Kivy 2.0.

heavyset_go• 6 years ago

If anyone's used Kivy or Beeware for mobile app development, I'd love to hear about it.

GirkovArpa• 6 years ago

How does Kivy compare to Sciter?

pestatije• 6 years ago

A cross-platform framework which does not support the web platform. What's the point? There are so many UI development frameworks, and so many of them are missing the web. This limits the options available enormously, and is forcing programmers into inconvenient and inappropriate solutions.

epse2• 6 years ago

Hey! I actually did my thesis on porting kivy to the Web and may I tell you, its going to be infinitely easier and faster to just develop your app for Web or hire a good webdev right now.

Nativescript angular can run both Web and native from 1 codebase if you like, but kivy is inherently hard to port

solarkraft2• 6 years ago

I really like the Kivy project's goals and the demos I saw were super fast and nice. But when I had a look at actually building something with it I discovered that the default UI is completely raster based, which is just a weird deal breaker.

inclemnet3• 6 years ago

If there was one thing I could wish to be revamped about Kivy it's the default widgets. There's a core of good ones, especially those that are most commonly used, but quite a few make bad design decisions like an over-reliance on images for styling. This is often much easier to work around than is probably obvious and maybe that's part of the problem, more experienced developers likely habitually sidestep the parts that don't work well. But on the other hand, it's quite a bit of work to revamp them (including documentation and dealing somehow with breaking changes it would introduce), unfortunately that has kept us from seriously addressing it so far.

hypervisorxxx• 6 years ago

Long time fan of kivy checking in here. Important if you wanna be off internet grid. Portal to OpenGL as well. Kivy hugely underrated and better than QT imho. Made a 2D skateboarding game and tried to get it working with buildozer on android back in the day (2017) Cheers to the devs.

tobijkl• 6 years ago

I love the idea of Kivy, an open-source, community-driven, cross-platform framework, but flutter delivers much nicer mobile apps, and QT a far better desktop apps. I do not think that I have ever used a cross-platform app that works as well on desktop as on mobile.

Kivy: Cross-Platform Python Framework for UI Development

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