Android on mm-dev

Set up Vim for Flutter

Thu, 08 Aug 2024 17:47:33 +0100

There are various ways of installing Vim plugins. I use vim-plug in my examples here but I’ll add links to instructions for each plugin so you can do it your own way.

Dart

As Flutter uses the Dart language, install Dart support for Vim. I add the following to my ~/.vimrc:

" Between the 'plug#begin()' and 'plug#end()' lines
Plug 'dart-lang/dart-vim-plugin'

Then I restart Vim and run :PlugInstall.

This adds syntax highlighting and auto-indentation of Dart code.

Language Servers

Language Servers/LSPs (LSP = Language Server Protocol but both terms are often used interchangeably) give your editor information about the structure of a language and enable it to do syntax highlighting and code completion, along with deeper functionality such as allowing you to jump to the definition of a function, do refactoring etc.

LSPs are used in Visual Studio for a lot of its advanced functionality but they can also be used in Vim. There’s more than one way of doing this but I use coc-nvim (despite the name it works in modern versions of Vim, not just Neovim).

Install the `coc.nvim` plugin in Vim

Using vim-plug I add the following to my ~/.vimrc:

" Between the 'plug#begin()' and 'plug#end()' lines
Plug 'neoclide/coc.nvim', {'branch': 'release'}

Again, I restart Vim and run :PlugInstall.

For other ways of installing just follow the instructions .

Install a Flutter LSP

Install the Flutter language server in CoC, coc-flutter. This provides lots of helpful functionality for working with Flutter in Vim as described in the link.

:CocInstall coc-flutter

This LSP needs to know where the Flutter SDK is installed. In Vim, run :CocList FlutterSDKs and make sure it finds at least 1 SDK. If not, add a line to CoC settings (:CocConfig):

"flutter.sdk.path": "$HOME/.local/flutter/bin"

You can find the correct path with which flutter in the terminal.
Originally, I had installed my Flutter SDK at /usr/bin. That caused invisible errors with coc-flutter as it couldn’t access the path properly to find the Flutter SDK. I was having trouble getting this step working. I then moved the Flutter SDK to $HOME/.local/flutter and everything started to work properly

`coc.nvim` settings

To change CoC settings the command :CocConfig can be used in Vim. On my system it opens up the file ~/.vim/coc-settings.json. You can open/edit this file directly but depending on your Vim configuration it may be in a different location.

Here are some of the settings I prefer:

{
  "diagnostic.checkCurrentLine": true,
  "diagnostic.enableMessage": "jump",
  "colors.enable": true,
  "suggest.noselect": true,
  "inlayHint": false
}

`"diagnostic.checkCurrentLine": true,`

By default, Coc will show you a diagnostic error or warning when your cursor is over the word causing the problem. Setting this to true means you only have to be on the same line as the error to see the dialog, not the exact word.

`"diagnostic.enableMessage": "jump",`

This diagnostic popups can be really helpful, but it’s all a bit frenetic for me, I’m a prefers-reduced-motion kind of person. Setting this to jump means they don’t pop up automatically, but can still be shown when I want to see them. I also add this line to ~/.vimrc:

nmap <silent> gh <Plug>(coc-float-hide)
nmap <silent> gl <Plug>(coc-diagnostic-info)

Which allows me to show/hide the diagnostics with gh/gl respectively.

`"colors.enable": true,`

This setting is for another CoC addition called coc-highlight. I installed this in Vim with:

:CocInstall coc-highlight

This adds various types of colour highlighting, but the one I was most interested in is how it will detect any colours (eg RGB or hex) in your code and change the colour of their text to give you a preview of them. This feature is enabled with the colors.enable line as above.

`"suggest.noselect": true,`

When you start typing a word, CoC will default to inserting its first suggested autocompletion word. This is a bit more ‘help’ than I like, so I add this setting to make the process more intentional.

`"inlayHint": false,`

By default CoC inserts inlay hints, for example if you haven’t added a type hint to indicate what kind of widget is being referred to somewhere, it will insert the <Widget> hint for you as a piece of magical ghost text.

These bizarre bits of text appear in the middle of lines of code, except they aren’t really there, you can’t select them or delete them and if you’re moving your cursor around it acts as if they don’t exist. I’m sure some people enjoy them, and for those people I’m glad that they exist. For me, they are disgusting, obnoxious devil-warts.

Thankfully, they can be vanquished by adding this line to the CoC settings.

Install Flutter

Thu, 08 Aug 2024 17:47:32 +0100

Follow instructions from https://docs.flutter.dev/get-started/install/linux/android

Download the flutter_*.tar.xz archive
Unpack the archive into $HOME/.local/bin (creates $HOME/.local/bin/flutter/bin)
At first I tried putting this at /usr/bin, but that caused invisible errors in coc-flutter as it couldn’t access the path properly to find the Flutter SDK
Add the new path as above to $PATH eg in ~/.profile

# ~/.profile
export PATH="$HOME/.local/bin/flutter/bin:$PATH"

For ARM64 architectures the Flutter SDK cannot be found at the above link, nor in the archives. In this case the SDK can be obtained by cloning the main flutter repo, then running a flutter command to trigger a download of dependencies
git clone -b main https://github.com/flutter/flutter.git
./flutter/bin/flutter --version

Agree to more licenses and get Flutter doctor to pass

First, agree to several laughably long licence agreements which Google knows full well that nobody reads.

flutter doctor --android-licenses

Then type Y and Enter for each prompt

Now run flutter doctor. It should pass every test except ‘Android Studio (not installed)’. If so, we’re ready to start building Flutter apps (with Android Studio not installed).

Sample project

You can make a really simple sample project to check that everything’s installed correctly and see how it works.

flutter create sample-project

This will create a sample-project directory with a Flutter app in it, a simple built-in demo of a button which counts up as you tap it.

To run the app:

cd sample_project
flutter run

Install the Android SDK

Thu, 08 Aug 2024 17:47:31 +0100

Getting the Android SDK set up manually can be tricky, I think the expectation is that most people will use Android Studio so not a lot of work has been put in to making manual installation user-friendly.

Pick a directory where you’ll keep the SDK

This is an important directory that will always store all the Android-SDK specific tools, platforms, build tools etc. Various bits and pieces need to know where these things are, so we’ll set some environment variables for them later.

I’m using $HOME/android_sdk/ in these examples.

mkdir $HOME/android_sdk

Install the SDK Manager

This is a set of command line tools used to install different versions of the SDK (for when you want to target different Android devices).

Based on Google’s instructions at https://developer.android.com/tools/sdkmanager.

From the downloads page (I had to scroll down a long way), download the cmdline-tools zip and unzip it to the directory you created above eg $HOME/android_sdk/
Inside the unzipped directory cmdline-tools make a ’latest’ directory and move all of the other contents of ‘cmdline-tools’ inside it (so you end up with cmdline-tools/latest/bin

You should end up with something like the following (I’m using tree to list the directory contents but don’t worry about that, just make sure your directories are in the right places):

$ tree -L 2 cmdline-tools/
cmdline-tools/
└── latest
    ├── NOTICE.txt
    ├── bin
    ├── lib
    └── source.properties

Add some environment variables to `~/.profile`

Make sure these make sense based on what we’ve done so far if you’ve used different directories to me.

# ~/.profile
export ANDROID_SDK_ROOT=$HOME/android_sdk
export PATH=$PATH:$ANDROID_SDK_ROOT/cmdline-tools/latest/bin
export PATH=$PATH:$ANDROID_SDK_ROOT/platform-tools

Source the profile with source ~/.profile. Then run sdkmanager and see if it does something. If you get command not found double-check everything and try rebooting.

My sdkmanager binary name clash (this won’t affect you but click to expand if you’re interested)

In my case I already had a binary installed with the name sdkmanager, as that’s the name Garmin use for their ConnectIQ SDK Manager. Apparently neither Garmin nor Google could foresee that anyone other than themselves might call their SDK manager software ‘sdkmanager’.

So I had to do some hacky stuff with bash aliases in ~/.profile to let the two live alongside each other, and remind me of the situation:

alias sdkmanager='echo "Use either *sdkmanager-garmin* or *sdkmanager-android*"'
alias sdkmanager-android=$ANDROID_SDK_ROOT/cmdline-tools/latest/bin/sdkmanager
alias sdkmanager-garmin=$HOME/.local/bin/sdkmanager

Accept SDK licences

The SDK licences must be accepted for everything to work.

sdkmanager --licenses

Then type Y and press Enter for each prompt

Install the Android toolchain

To pass the ‘Android toolchain’ step of flutter doctor (in a bit) we need 3 things:

Platform tools (generic)
A valid platform
Build tools to match the platform

Various instructions online will tell you to do things like sdkmanager "platform-tools" "platforms;android-33" (ie pass multiple arguments to sdkmanager), but as observed in this StackOverflow answer if using the command line tools, the platform tools need to be installed via separate commands ie:

sdkmanager 'platform-tools'
sdkmanager 'platforms;android-33'
sdkmanager 'build-tools;33.0.2'

If the installation has worked correctly you should end up with something like:

$ tree -L 1 android_sdk/
android_sdk/
├── build-tools
├── cmdline-tools
├── licenses
├── platform-tools
└── platforms

Another weird, me-specific problem I encountered…

At first, my installations weren’t appearing in my android_sdk directory and Flutter tools were complaining about not being able to find the Android SDK.

Forcing the SDK path like this worked: sdkmanager --verbose "platform-tools" --sdk_root=$HOME/android_sdk/

But something smelt wrong, as the original sdkmanager install commands seemed to be completing without error. I investigated this by running the following:

sdkmanager 'platform-tools' --verbose

Which revealed that they were going into:

/data/data/com.termux/files/usr/share/android-sdk/

This is because I was on Android using Termux, in a proot container, and I had previously installed the SDK in the main (non proot) Termux environment. This was not needed any more so I deleted the other installation.

This is an exotic situation and you’re probably not as stupid as I am to get into this situation, but maybe this note will help in some other situation.

Dependencies and Environment

Thu, 08 Aug 2024 17:47:30 +0100

To get started I’m presuming you have a Linux installation of something like Debian/Ubuntu.

General Dependencies

Git

You probably already have this but just in case:

sudo apt install git

Ensure Java JDK is installed and recent enough

sudo apt install openjdk-17-jdk

Stuff Flutter Needs

The latest info about this should be here but at time of writing:

sudo apt-get install -y curl git unzip xz-utils zip libglu1-mesa

And some other tools Flutter uses:

sudo apt install clang cmake ninja-build

If using Chromium browser instead of Chrome

The Android SDK likes to know where Chrome is on your system. I use Chromium and the SDK can’t find it.

So I export an environment variable to let Flutter know where to find Chromium eg in ~/.profile

export CHROME_EXECUTABLE=/usr/bin/chromium

Parts of the SDK

Thu, 08 Aug 2024 17:47:30 +0100

There are several components making up the SDK. I’ll list them here along with examples of how they can be installed later on when the SDK manager is set up and working.

This is just an overview to help your mental model of what’s what, we’re not installing anything just yet.

We download them as a zip and place them in a specific directory, as detailed later.

Command Line Tools

These commands can do several things like signing and optimising APKs, but the main one we are interested in is sdkmanager. This is the command we use to install the other tools.

Platform Tools

These are tools for interfacing with Android which you may already be familiar with, such as adb and fastboot.

sdkmanager 'platform-tools'

Platforms

A platform represents a specific version of Android. It includes multiple system images, which the device emulator uses to emulate various devices on that platform.

Information used to compile your app for this platform version, and source code to be used for debugging are also included.

Multiple platforms can be installed alongside each other on the same system.

sdkmanager 'platforms;android-33'

Build Tools

These are tools used for building Android apps. I’m not 100% clear on what these are and why they are different from Platform Tools, it seems that they were part of Platform Tools in the past but have been sectioned off into their own thing.

Anyway, we need them. Usually use the latest version, but sometimes if you’re targeting specific platforms eg older ones, errors may indicate that you need an older version.

sdkmanager 'build-tools;33.0.2'

Intro

Thu, 08 Aug 2024 17:47:29 +0100

Given the choice, I’d rather avoid huge complex apps like Android Studio. They use a lot of system resources and are very GUI/point-and-clicky. Those things definitely have their place but I prefer keyboard control where it makes sense, and for me programming in Flutter is one of those situations.

A lot of what Android Studio does behind the scenes is automatically editing text files and running shell commands such as flutter run, flutter build and so on. If you’re comfortable with the terminal these commands are fairly simple to run manually.

As an IDE Android Studio also helps with stuff like syntax highlighting, code completion, refactoring etc. If you’re into Vim it can be set up to give you these pleasantries. I’m sure there is stuff Android Studio can do that Vim can’t, but whatever it is I’m not missing it and I feel good when I use Vim.

I’ve set up a couple of systems with this Flutter dev environment recently and hit some stumbling blocks. They weren’t too hard to resolve but I wanted to write up the process for future reference and to help anybody else in a similar situation.

The Bad Parts

Fri, 05 Apr 2024 11:44:43 +0100

The Low Memory Killer Daemon - Official Docs.

This feature of modern Android versions kills tasks (/apps) when it thinks they are causing memory-related performance problems. It can feel pretty heavy-handed, with apps abruptly closing at seemingly random intervals.

In practice this can irritate but I’ve never lost any work because of it. The most noticeable occurrence is when Termux:X11 closes — my Linux desktop suddenly shuts down! Sounds terrible But actually my Vim buffers are constantly auto-saved, my browser tabs are stored… I just have to restart the session, then Tmux, then maybe a couple of other items. I’m back up and running in 1-2 minutes, and this problem might occur once or twice per week at the most.

There are various ways to tweak the daemon though, search for terms like ‘disable android oom killer’, ’tweak low memory killer daemon android’ etc.

Missing Tools for ARM Architecture

As the types of CPU in Android devices (usually ARM) are not the same as those used in laptops/desktops (usually X86), the standard desktop versions of software can’t be installed and compatible versions must be available (unless you want to compile them yourself).

This isn’t as bad as it sounds as the package manager for whichever distro you use will automatically pull in the correct version for your CPU architecture. Some software might be missing though.

A couple of specific gaps in the system affect me:

Garmin Monkey C
Garmin apps are written in their own language ‘Monkey C’, which has to use their own Java-based compiler and device simulator. As far as I can tell this isn’t happening on ARM. It was hard enough to get it working on Linux and Vim as they presume Windows/VSCode in their tutorials, so once I achieved that I didn’t take it any further.
Flutter cross-compilation
The situation with Flutter is strange. Flutter is used to make multi-platform apps, so the same code can output apps for Linux, Android, Windows etc. I can build a Linux (ARM64) binary on my Android Ubuntu… and I can build an Android binary on my (normal, X86 desktop) Linux. But I can’t build an Android binary from Android. Apparently people were able to do this on older versions of Flutter, so it seems like Google (who control Flutter) intentionally stopped supporting it.

Fingers crossed!

Mine is a niche use-case and I understand that I can’t expect organisations to support such a tiny minority as ARM Linux. Apple’s M1/M2/M3 ARM chips are doing very well, which is great if you’re into that but I don’t enjoy their ecosystem.

So for now I need to hang on to my X86 desktop. But I hope ARM continues to gain recognition as more than a mobile phone CPU and can be used for more development tasks in future.

Software

Fri, 05 Apr 2024 11:44:41 +0100

Although this is all in relation to working on Android, the software I use is generally the same as if I was on a Linux desktop. That’s kind of the point, nowadays I can use almost the same environment on Android as I can on my desktop.

Termux

Termux is a brilliant free terminal app and Linux environment for Android. It has most of the Linux commands I need and I can install git, Vim, Tmux, mutt, ImageMagick and the majority of the terminal software I like to use. For certain jobs such as scripting, SSH sessions and writing, this is all I need.

Termux can run non-terminal, graphical apps too, but you won’t be able to see them. That’s what the next app is for.

Termux:X11

This amazingly useful app describes itself as being in early development, but I’ve been daily-driving it for months without significant issues.

Termux:X11 is an X Server for Termux. This allows you to install graphical Linux apps, as long as they are available for your system architecture (ie AArch64 — or ARM64 as it’s known — for most modern Android devices).

This means I can run, directly on my tablet:

Desktop Firefox (so, full developer tools)
Desktop Chromium (this was quite hard to get installed and isn’t the absolute latest version but is still very useful for development)
Krita/Inkscape/GIMP for image processing
Thunar file manager
Audacity (using PulseAudio over the network to pipe the audio up to Android by using the devices own IP address… I’m sure this creates some delay/latency but I’ve not noticed it in practice and for my typical usage of minor adjustments to audio files it works well)

PRoot Distro

This is a ‘container environment manager’ and allows you to easily install, uninstall, backup and restore Linux distributions, alongside/on-top-of Android, sharing the kernel.

It’s really simple to use, eg installing Debian Linux is a matter of opening Termux and entering:

proot-distro install debian

Then for a shell login:

proot-distro login debian

PRoot Distro provides a nice choice of distros including:

Alpine Linux (edge)
Arch Linux ARM
Artix Linux (AArch64 only)
Debian (stable)
Fedora 38 (AArch64 only)
Manjaro (AArch64 only)
OpenSUSE (Tumbleweed)
Pardus (yirmibir)
Ubuntu (23.10)
Void Linux

You can install as many distros as you want and swap between them easily. Each distro just sits in a directory on the Android device. Using the backup tools the entire system can be bundled up as a single archive file and moved over to another Android device.

Window Management

I believe that the best user interface (actually, interface of any kind) is one that I don’t even notice exists. It doesn’t shout at me, it doesn’t wow me with animations and eye-candy. It allows me to get to the tools I need to get the job done and stay immersed in the task. It is at peace with itself enough to take a back seat and not demand attention. It is, conceptually, transparent.

A lot of people like the gestural UI featured in ‘Minority Report’. I like the film, and the scene with Tom Cruise manipulating the UI is well produced and fun to watch. But as a UI it’s terrible! Hugely inefficient with all those big sweeping hand gestures, it’s not quick or practical. I don’t want to have to perform interpretive dance to use my computer (nor watch my computer doing little performances when I’m trying to get stuff done).

I found similar sentiment in this Daring Fireball article about the Apple Vision Pro:

“To me the Macintosh has always felt more like a place than a thing. Not a place I go physically, but a place my mind goes intellectually. When I’m working or playing and in the flow, it has always felt like MacOS is where I am. I’m in the Mac.

“Interruptions — say, the doorbell or my phone ringing — are momentarily disorienting when I’m in the flow on the Mac, because I’m pulled out of that world and into the physical one.”

I am nearly exactly like this too, except I don’t want to feel like I’m “in the Linux” (and definitely not “in the Mac” or “in Windows”!). I don’t want to be aware of that layer of abstraction at all. I don’t mind feeling that I’m “in Vim”, but really I want to be “in the code” that I’m editing. I specifically don’t want to feel the manicured claw of a corporate behemoth like Apple or Microsoft on my shoulder… but that’s just me.

I’d rather forget that my OS(/window manager) exists. It’s a facilitator, not an end in itself.

DWM: Tiling Window Manager

I used to prefer larger screens and multiple monitors. I knew about the concept of workspaces but they sounded annoying and fiddly. It took me a long time to give them a chance and it happened accidentally, as a side-effect of trying a tiling window manager.

Very briefly, a tiling window manager organises your windows into tiles, meaning instead of having oddly-sized overlapping windows floating around making a confusing mess of your screen and using space inefficiently, your screen splits into fractions, each being filled by an app. If you have too many apps on the screen they can go onto other screens, or ‘workspaces’. Personally I tend to run most apps fullscreen most of the time, switching between them with keyboard shortcuts.

I started with i3 Window Manager, which is a really nice piece of software. After a few years of using it though I realised I didn’t use most of its features, so landed on the very minimal Suckless Tools DWM.

With workspaces, each app can have its own screen and can be accessed instantly via a keyboard shortcut. With familiarity this becomes a chord in muscle memory, a hand-shape to mash at keyboard. I have habits for where I keep each app, so eg my terminal is in workspace 1 so [Alt]+[1] puts me in the terminal. [Alt]+[9] puts me in FireFox and so on.

I’ve [Alt]+[Tab]bed through apps in the past. Workspaces are similar except you know the keyboard chord will take you directly to the app you want, you don’t have to play ‘stop the magical app carousel at the right time’… which may be a drawback for some I guess, as carousels can be fun.

We can only focus on one thing at a time, that’s how attention works. I can see some uses for multiple screens eg if you have to monitor lots of things, like real-time charts or meters. In that case your peripheral vision is good at detecting change/motion so you can make use of all the space. But personally I’m completely over large/multiple displays. In my circumstances, they waste power, waste space, and are just not necessary.

Hardware

Fri, 05 Apr 2024 11:44:40 +0100

Hardware

My favourite and most commonly-used device is my Samsung Tab S8 Ultra:

14.6" OLED display
2960x1848 resolution
16:10 aspect ratio
8-core, 4nm processor
8GB RAM

The OLED (my favourite display tech along side e-ink) screen is gorgeous. Black is really black and running everything in dark OLED (black) UI modes gets a little more out of the battery too.

This tablet is roughly on par with average modern laptops in terms of power, but has some advantages for me.

Ergonomics

This is the main reason I generally prefer a tablet over a laptop. With a laptop the screen is attached to the keyboard, meaning:

The display is always too low, so…
you hunch over…
which is bad for your back, and…
…affects your breathing, as…
- your shoulders turn inwards and compress your chest cavity, so…
- your breaths will be shorter and more shallow…
- increasing a tendency towards feeling stressed or anxious

This may seem over-the-top, but we programmers spend a lot of time sitting at our machines. There’s no such thing as a good position to sit in all day, our bodies expect and require movement (I certainly need a lot more) — but some positions are better than others.

Another benefit of using portable/mobile devices for work is that you aren’t chained to a desk, so can move around to different seating positions throughout the day. As a self-contained unit a laptop is good for this too, but you’re still stuck with the screen and keyboard being attached to one another.

I attach the tablet to a monitor arm so I can position it at a good height (ie with the top of the screen being just below eye level). But if I want to spend some time in a different position, I have a simple tablet stand which folds flat (so takes up very little storage space) and can easily be placed on top of books or boxes to elevate my tablet.

Tablet arms
Foldable tablet stand

Choice of Input Devices

In the past I’ve preferred ThinkPads for their great keyboards and little red TrackPoint pointing devices — I have an old but lovely X230 for when I do feel the need for a laptop.

Nowadays though, my favourite combo is a mechanical keyboard and trackball (the ‘fingers on top’ type of trackball suits me better than the ’thumb at the side’ type).

Of course these devices can be attached to laptops too, but then the laptop’s own keyboard and pointing device are just sitting there doing nothing. Laptops are good for travelling but for me sitting at home they’re a waste.

They used to make TVs with DVD players built-in, and common advice was that it wasn’t a wise buy, as if the DVD player stopped working you just had a wasted lump of electronics attached to your TV. I feel like this about laptops.

Ergodox Mechanical Keyboard

I like to use an Ergodox mechanical keyboard which I built myself from a kit and maintain (due to my terrible soldering joints regularly failing). This is a split keyboard, meaning it comes in 2 halves which can be positioned with a gap in the middle, allowing me to keep my arms a comfortable distance apart and avoid the hunching and bad posture. The keyboard is also programmable via the open source firmware QMK (great project btw).

As time goes by I am gradually removing keys from my layout and moving towards a layers/chording method of typing, meaning you have fewer keys and use more key combos. I’m ultimately aiming for a 40% layout (which vaguely means 40% of the number of keys on a normal keyboard). Fewer keys means fewer hand contortions and stretching fingers to fewer awkward positions, plus it makes the hardware smaller. Once I’m comfortable with that smaller number of keys I’ll build myself a Bluetooth LE Ferris keyboard or something similar.

My Ergodox is a wired USB version but I use it over Bluetooth via a BT500 Bluetooth adapter which converts any USB keyboard/mouse into Bluetooth. The BT500 is quite expensive for what it is (about $40) but I doubt they sell huge numbers of them so probably don’t have the economies of scale to make them cheaper. I had to order from the USA and wait a while to get it, but it’s a pretty cool and useful device.

Deft PRO Trackball

My trackball is a DEFT Pro. It works well for my purposes and feels comfortable enough. I try to use the keyboard instead of the pointer as much as possible but sometimes a mouse/trackball is needed, eg when editing images.

Power Management

Android/mobile devices treat this as an important feature whereas laptops don’t always take enough care over it, especially with Linux (where power management isn’t always the best, partly because device manufacturers don’t work as closely with Linux as they do Microsoft). This isn’t true for all laptops though, and things seem to be improving.

Most Android devices use ARM CPUs, which give strong performance for relatively low power usage.

I admit that Windows and MacOS tend to be better-tuned for power efficiency, but if I had to use those OSes I’d be wishing for my battery to die, just so I could stop. So, swings and roundabouts.

Adaptable and Easy to Store

I can be writing code one minute and very quickly change to watching a film or casual web browsing handheld mode the next.

As I’m often relying entirely on solar power for my electricity, being able to minimise the number of devices I need to keep charged up is a real benefit for me.

Also, living in a small space, tablets are flat and thin — so very efficient in terms of storage. Several can be stacked up on top of each other and take up no more space than a large book.

Intro

Fri, 05 Apr 2024 11:44:38 +0100

I get a lot of my development work done on Android devices. That usually means a large tablet, but it’s not impossible to get work done on smaller tablets or even phones (although the smaller you go, the harder it is to maintain ergonomics and practicality).

With Termux/PRoot Distro/Termux:X11 (explained below) I can run all of my most-used Linux apps just like I was sitting at a desktop, silently (ie no fans) and efficiently.

Performance on my S8 Ultra tablet is great — not as fast as the latest most powerful laptops but perfectly comfortable for my usage patterns.

A shortcut to a simple Termux script means I can tap an icon on my Android home screen and boot into the beautiful emptiness of an Ubuntu DWM session in about 5 seconds.

Android Bluetooth Keyboard Mapping

Thu, 08 Feb 2024 12:05:30 +0000

I use Bluetooth keyboards with Android a lot, and often want to remap keys (eg swapping CAPS_LOCK to CTRL_LEFT).

Maybe it’s a failing in my search technique or I’m doing something that nobody else does nowadays, but whenever I search for info about this I find really old articles with out-of-date info, or just links to apps. To be fair Key Mapper is good and I do use it, but sometimes I just want to be able to do it at a system level without requiring extra apps.

To remap keys in Android, you need to edit a particular keylayout *.kl file, specific to the device (eg Bluetooth keyboard) you want to re-map. The files have names like Vendor_04e8.kl. The name is derived from various properties of the device, such as vendor ID, product ID and other things as explained here in the Android docs.

The sticking point for me, for ages, was that I had trouble finding the vendor and product codes and, consequently, the correct file to edit. In Linux I’d use lsusb or bluetoothctl or something like that, but on Android even in the wonderful Termux, these things don’t work properly for reasons I haven’t completely wrapped my head around, related to security and/or the way Android and its underlying Linux kernel inter-relate.

Problem 1: Finding which keylayout file needs to be edited

In Termux or whichever shell/terminal you use, do su to log in as superuser
Do dumpsys and wait for it to finish. It can take a while (couple of minutes on some of my devices)…
If I don’t do this step, on some devices the next step doesn’t work… I hate this kind of situation as I have no idea why this should work and it feels nonsensical, but all I know is it fixed the problem when I encountered it.
Do dumpsys input to narrow the output
Even this input-specific command outputs quite a lot. I tend to just take my time and scroll through it, but you can make it easier by trying something like:
dumpsys input | grep -i -A12 bluetooth
- The -i means case-insensitive
- The -A12 means show the matching line plus the 12 lines After it
- You may want to tweak the number but for me 12 was good
In the output, look for a description for your device (mine is Device 45: Bluetooth 3.0 Keyboard), and soon after that you’ll find a line like KeyLayoutFile: /system/usr/keylayout/Vendor_04e8.kl — that’s the *.kl file you need to edit to remap your keyboard

Problem 2: Editing system files on modern Android

On modern versions of Android, even if you have root, it’s not possible to directly edit files in the /system/ directory (it is mounted as read-only).

The way around this is to make a Magisk module. This is simpler than it might sound. The basic idea is that you create a folder in /data/adb/modules, (eg in my case I use mm, so /data/adb/modules/mm/). Inside that folder, you can create files and folders which Magisk will overlay onto the system at boot time, eg:

/data/adb/modules/mm/system/usr
# becomes
/system/usr

/data/adb/modules/mm/system/usr/keylayout/Vendor_04e8.kl
# becomes
/system/usr/keylayout/Vendor_04e8.kl

Now you can edit the keylayout file to make your changes, eg to change CAPS_LOCK to CTRL_LEFT on my keyboard it’s:

# key 58    CAPS_LOCK
key 58    CTRL_LEFT

Other apps which might be useful

Depending on your Android device and software version, it can be difficult/confusing to find the right key codes. I find that one or another of the apps below usually gets me what I need:

BendyStraw (Android App)

Tue, 10 Oct 2023 13:17:20 +0100

If you don’t already know, NewPipe is a privacy-friendly, ad-free Android app for accessing YouTube. It’s a great piece of software and I use it all the time.

NewPipe works without an account. You can subscribe to channels, save playlists and do other useful things, but everything is saved locally on your device (and I love that it works like this).

I use NewPipe on several Android devices. Over time I’ve ended up with different playlists and subscriptions on each device, and sometimes I can’t be sure which device I need to use to find a certain song or video. To help with this I made BendyStraw.

Multiple databases in colour-coded tabs
Copy streams from one playlist to another
Selecting streams to delete, copy or move
Create new playlists

BendyStraw imports NewPipeData-*.zip files and lets you:

Open multiple zips at the same time, so you can combine data from several devices
Delete Copy Move Rename your custom playlists
Delete Copy Move streams from one playlist to another
Delete Copy Move channel subscriptions between databases
Delete Copy Move remote (bookmarked) playlists
Re-order playlists, sorting the streams by Title, Channel or Length (just tap the column headings in the tables)
Streams (audio/video) can be opened directly from BendyStraw, as the URLs are clickable
- If you set video links (in your Android settings) to open in NewPipe you can make a split-screen view and jump around your playlists
Export playlist as raw text, for example to be used with yt-dlp
Dark/light themes

After editing simply export a new zip file, then import it back into NewPipe.

Installation

F-Droid

Search for ‘bendystraw’ (all one word) in the F-Droid app, or find it at https://f-droid.org/en/packages/rocks.mm_dev.BendyStraw/.

Direct download

The apks are also directly available on the Codeberg releases page.

How to Use

Expand all

1. Export your database from NewPipe

In NewPipe tap Settings Backup and restore Export database
This will create a file on your device with a name like NewPipeData-2023-09-01.zip

2. Import it into BendyStraw

In BendyStraw, tap the button with the add/plus icon, and select the file you just exported

3. Edit with BendyStraw

Custom playlists have icons at the top which you can click to:

Delete the playlist
Copy the playlist to another zip (you need more than one zip added to do this)
Export the playlist as a plain text file, which for example can be used with yt-dlp

Tap on a playlist name to edit it, and tap outside (or press return on the keyboard) to finish.

4. Export from BendyStraw

In BendyStraw tap the export button (the arrow icon on the bottom-right of the screen)
This will create a new file named like the original but with -bendy-straw at the end, so NewPipeData.zip is saved as NewPipeData-bendy-straw.zip

5. Import it back into NewPipe

In NewPipe tap Settings Backup and restore Import database and select the file you just saved
After importing the database, NewPipe will ask if you also want to import settings, if you’re not sure what this means just tap ‘cancel’, your current NewPipe settings will remain unchanged

JSON Playlist Import

BendyStraw can import playlists from a JSON file. This is a new and basic feature which has some requirements and limitations.

Show the JSON Import Button

The button is hidden by default

Go to the preferences screen (hamburger menu in top-right corner)
Tick the ‘Show JSON Import Button’ box
Open at least 1 database
The button only shows when there is a database open, as it imports the JSON into the currently-opened database

Limitations

We assume that all playlist entries are YouTube streams.
Although NewPipe is able to handle streams from other services too, for now this import feature is just for YouTube

The JSON import format has been designed to prefer simplicity over richness of data. This comes with some pros and cons:

Several stream attributes (eg ‘uploader URL’, ‘duration’, ‘upload date’, ‘view count’, ’thumbnail’) are omitted initially
After import into NewPipe, before the playlist has been played, the above details (attributes) will be missing (so eg the thumbnail will just be a grey blank)
The first time each stream is started, NewPipe will grab the missing details for the stream and fill in the database

Requirements

JSON playlists will be imported into whichever database is currently open in BendyStraw.

The general (pseudocode) schema is:

{
  "PLAYLIST_NAME": [ARRAY_OF_STREAMS],
  "PLAYLIST_NAME": [ARRAY_OF_STREAMS],
  etc...
}

`PLAYLIST_NAME`

Is expected to be unique (if it isn’t, identically-named lists will be combined into 1 playlist)
If a playlist with exactly the same name already exists in the target database, entries from the JSON will be appended to that existing database

`ARRAY_OF_STREAMS`

Each stream must be an object with named properties as follows:

I use comments in this explanation but remember comments are not valid JSON — do not include comments in your JSON

{
  // These are required
  "stream_type": "VIDEO_STREAM", // or 'AUDIO_STREAM'
  "title": "Seasonal Affective Disorder",
  "url": "https://www.youtube.com/watch?v=3RJ5GftYT2c",
  "uploader": "Hidden Valley Bushcraft", // Uploader/channel name,

  // These below are optional. NewPipe will update them when the stream is loaded, so they only have meaning on first import before the playlist has been played.
  // It's probably better to omit them but they are allowed if you want to use them.
  "uploader_url": "https://www.youtube.com/channel/UCB7BPYlL4f5j5R1Y7HUgeVg", // Uploader/channel URL 
  "duration": "120", // Length of stream in seconds 
  "view_count": "1273621", // Number of times the stream has been viewed on YouTube --- simple number ie no commas, abbreviations etc 
}

Complete Example JSON

Below is some complete sample JSON. If this was imported into a database in BendyStraw it would do one of the following:

Create 2 new playlists (“Tech Things” and “Good Songs”)
Or (if playlists with those names already existed) then the streams would be appended to those existing playlists

{
  "Tech Things": [
    {
        "stream_type": "VIDEO_STREAM",
        "title": "Free software, free society: Richard Stallman at TEDxGeneva 2014",
        "url": "https://www.youtube.com/watch?v=Ag1AKIl_2GM",
        "uploader": "TEDx Talks",
        "uploader_url": "https://www.youtube.com/channel/UCsT0YIqwnpJCM-mx7-gSA4Q"
    },
    {
      "stream_type": "VIDEO_STREAM",
      "title": "Shenzhen: The Silicon Valley of Hardware (Full Documentary) | Future Cities",
      "url": "https://www.youtube.com/watch?v=SGJ5cZnoodY",
      "uploader": "Wired UK",
      "uploader_url": "https://www.youtube.com/@wireduk"
    }
  ],
  "Good Songs": [
    {
        "stream_type": "VIDEO_STREAM",
        "title": "Aztec Camera - Somewhere In My Heart (Official Music Video)",
        "url": "https://www.youtube.com/watch?v=2w1Q8ZkXZ1Q",
        "uploader": "RHINO",
        "uploader_url": "https://www.youtube.com/channel/UCWEtnEiVwUy7mwFeshyAWLA"
    },
    {
        "stream_type": "VIDEO_STREAM",
        "title": "Imagine Dragons - Thunder",
        "url": "https://www.youtube.com/watch?v=fKopy74weus",
        "uploader": "ImagineDragonsVEVO",
        "uploader_url": "https://www.youtube.com/channel/UCpx_k19S2vUutWUUM9qmXEg"
    },
    {
        "stream_type": "VIDEO_STREAM",
        "title": "𝑰𝒕'𝒔 𝑨 𝑯𝒆𝒂𝒓𝒕𝒂𝒄𝒉𝒆 -Bonnie Tyler (Cover by Yhuan) #gutomversion #hitback #goodvibestambayan #yhuan",
        "url": "https://www.youtube.com/watch?v=AQCm7VWyg-U",
        "uploader": "Yhuan Official",
        "uploader_url": "https://www.youtube.com/channel/UCDxVjSFhfiPGispcK9o0qzw"
    }
  ]
}

FAQ

Expand all

What’s in the `zip` files?

NewPipe exports a zip file, containing 2 files:

newpipe.db: A database which has all the info BendyStraw uses, such as your playlists and channel subscriptions, plus other things like your watch history
newpipe.settings: Your NewPipe settings and preferences

For simplicity BendyStraw sometimes refers to the zip file as the database, because that’s the file NewPipe works with for imports/exports.

Is my data private?

Yes! This is important to me as a developer. BendyStraw only works with the tables in the database which it requires to let you do your editing. It doesn’t look into other things like your settings or watch history and it doesn’t send your data to any servers or share it with anybody. There’s no tracking and no adverts or anything like that.

What happens to my NewPipe settings?

BendyStraw doesn’t look inside them or change them.

If you edit zips from multiple devices, or old/archived zips, be aware that your new zip will have the settings from whichever original file you opened. So be careful not to overwrite settings with an old version.
When you import your new zip into NewPipe the simplest thing to do is just tap ‘cancel’ when it asks if you want to also import settings.

I’ve opened multiple databases but don’t see enough tabs

The tabs can scroll off the edge of the screen, swipe left/right on the tab bar to see any tabs which have overflowed.

You can also swipe left or right on any blank area to switch tabs.

How do I use an exported text playlist?

If you have yt-dlp installed, you can batch download all of the files from the playlist like so:

In BendyStraw locate the playlist and tap the ’export’ button
Check the dialog to see where the text file will be saved
In your terminal run yt-dlp --batch-file [path_to_text_file.txt]

For more info check out the yt-dlp github.

Can I export an M3U playlist?

I originally did build this functionality, only to find that links to eg YouTube streams no longer work in m3u playlists. This is true for the players I tested and to the best of my knowledge.

If I’m wrong about this, you have some other relevant info, or would like to see some other export format, please let me know.*

I’d be happy to revisit this if it’s useful.

hello@mm-dev.rocks

Why do I need to grant ‘all files access’ permission in Android 13?

BendyStraw needs to work with files from a different app (NewPipe). The way permissions have changed in Android 13 makes this complicated, as document files (ie non-media files such as .zip) can only be read from and written to the directory belonging to the app that created them. The only simple way to keep the app easy to use is to ask for these permissions.

BendyStraw has no interest in doing anything unexpected to your filesystem. The code is open source, so any developer can check to make sure that it only does what it says it does.

Android on mm-dev

Set up Vim for Flutter

Dart

Language Servers

Install the coc.nvim plugin in Vim

Install a Flutter LSP

coc.nvim settings

"diagnostic.checkCurrentLine": true,

"diagnostic.enableMessage": "jump",

"colors.enable": true,

"suggest.noselect": true,

"inlayHint": false,

Install Flutter

Follow instructions from https://docs.flutter.dev/get-started/install/linux/android

Agree to more licenses and get Flutter doctor to pass

Sample project

Install the Android SDK

Pick a directory where you’ll keep the SDK

Install the SDK Manager

Add some environment variables to ~/.profile

Accept SDK licences

Install the Android toolchain

Dependencies and Environment

General Dependencies

Git

Ensure Java JDK is installed and recent enough

Stuff Flutter Needs

If using Chromium browser instead of Chrome

Parts of the SDK

Command Line Tools

Platform Tools

Platforms

Build Tools

Intro

The Bad Parts

The Low Memory Killer Daemon - Official Docs.

Missing Tools for ARM Architecture

Fingers crossed!

Software

Termux

Termux:X11

PRoot Distro

Window Management

DWM: Tiling Window Manager

Hardware

Hardware

Ergonomics

Choice of Input Devices

Ergodox Mechanical Keyboard

Deft PRO Trackball

Power Management

Adaptable and Easy to Store

Intro

Android Bluetooth Keyboard Mapping

Problem 1: Finding which keylayout file needs to be edited

Problem 2: Editing system files on modern Android

Other apps which might be useful

BendyStraw (Android App)

Installation

F-Droid

Direct download

How to Use

1. Export your database from NewPipe

2. Import it into BendyStraw

3. Edit with BendyStraw

4. Export from BendyStraw

5. Import it back into NewPipe

JSON Playlist Import

Show the JSON Import Button

Limitations

Requirements

PLAYLIST_NAME

ARRAY_OF_STREAMS

Complete Example JSON

FAQ

What’s in the zip files?

Is my data private?

What happens to my NewPipe settings?

I’ve opened multiple databases but don’t see enough tabs

How do I use an exported text playlist?

Install the `coc.nvim` plugin in Vim

`coc.nvim` settings

`"diagnostic.checkCurrentLine": true,`

`"diagnostic.enableMessage": "jump",`

`"colors.enable": true,`

`"suggest.noselect": true,`

`"inlayHint": false,`

Add some environment variables to `~/.profile`

`PLAYLIST_NAME`

`ARRAY_OF_STREAMS`

What’s in the `zip` files?