Building flutter apps

1. Self-building

Use --target-backend-type option to select display backends. Default is Wayland.

Build mode	Target backend	Command
release	wayland	flutter-elinux build elinux
	x11	flutter-elinux build elinux --target-backend-type=x11
	gbm	flutter-elinux build elinux --target-backend-type=gbm
	eglstream	flutter-elinux build elinux --target-backend-type=eglstream
debug	wayland	flutter-elinux build elinux --debug
	x11	flutter-elinux build elinux --debug --target-backend-type=x11
	gbm	flutter-elinux build elinux --debug --target-backend-type=gbm
	eglstream	flutter-elinux build elinux --debug --target-backend-type=eglstream
profile	wayland	flutter-elinux build elinux --profile
	x11	flutter-elinux build elinux --profile --target-backend-type=x11
	gbm	flutter-elinux build elinux --profile --target-backend-type=gbm
	eglstream	flutter-elinux build elinux --profile --target-backend-type=eglstream

2. Cross-building from x64 to arm64

Cross-building requires knowledge (Not easy, you might get build errors). You need to prepare your sysroot which is for cross-building for your target device by using --target-sysroot. Also, Use --target-arch option to specify arm64 targets. Default is current host CPU architecture.

$ flutter-elinux build elinux --target-arch=arm64 --target-sysroot=<path_to_target's_sysroot>

Example

There are some ways to create a sysroot like Yocto, buildroot, and so on. Here, we show an example using a sysroot for arm64v8/ubuntu:18.04 docker image, but using sysroot and toolchain for your target device is better.

Install cross-build tools

$ sudo apt install gcc-aarch64-linux-gnu g++-aarch64-linux-gnu
$ sudo apt install libstdc++-8-dev-arm64-cross

Create sysroot for arm64

First, install Docker by following Install Docker Engine on Ubuntu.

S sudo apt install qemu-user-static

$ sudo docker run -it arm64v8/ubuntu:18:04

In docker:

apt install clang cmake build-essential \
            pkg-config libegl1-mesa-dev \
            libxkbcommon-dev libgles2-mesa-dev
apt install libwayland-dev wayland-protocols
exit

Copy sysroot from the container to host:

$ sudo docker ps -a
CONTAINER ID   IMAGE                 COMMAND   CREATED       STATUS                   PORTS     NAMES
f367a6b0316f   arm64v8/ubuntu:18.04  "bash"    4 hours ago   Exited (0) 4 hours ago   interesting_knuth
$ mkdir ubuntu18-arm64-sysroot
$ sudo docker cp f367a6b0316f:/ ubuntu18-arm64-sysroot

Build flutter apps

$ flutter-elinux build elinux --target-arch=arm64 \
     --target-sysroot=<Absolute_path_to>/ubuntu18-arm64-sysroot

Troubleshooting

If you get the following error, use --system-include-directories option.

/usr/bin/../lib/gcc-cross/aarch64-linux-gnu/9/../../../../include/c++/9/casse
rt:43:10: fatal error: 'bits/c++config.h' file not found
#include <bits/c++config.h>
         ^~~~~~~~~~~~~~~~~~

$ flutter-elinux build elinux --target-arch=arm64 \
     --target-sysroot=<Absolute_path_to>/ubuntu18-arm64-sysroot \
     --system-include-directories=/usr/aarch64-linux-gnu/include/c++/${version}/aarch64-linux-gnu

3. Build artifacts

The artifacts will be put in build/${target-arch}/${build-mode}/bundle.