Run custom command before flutter build?

Question

I'm building a flutter app that uses protocal buffers and I would like to compile the .proto file during the build process. How can I run a custom shell command before the dart compilation of a flutter build?

Answer 1

Flutter doesn't have this capability yet, it's kind of better to have a pre-build script.

Simple Pre-build Script

my-pre-build.sh

# my-pre-build.sh (run some commands)

Usage

./my-pre-build.sh && flutter build apk

Using Make to Abstract the Build

You could also abstract the build using something like a Makefile, which makes things simpler in my opinion.

Makefile (in root of your project)

# Build for Android (runs build-proto first)
build-apk: build-proto
    flutter test
    flutter build apk

# Build for iOS (runs build-proto first)
build-ios: build-proto
    flutter test
    flutter build ios

# Proto generation (calls terminal proto commands)
build-proto:
    proto-native-lib compile -f *.proto

Usage

make build-android
make build-ios

This is a useful way to bundle repetitive commands and reuse scripts between different build types.

Answer 2

I believe you can do this in Android Studio.

1. Go to Run > Edit Configurations

2. Add a new Shell Script configuration from (+) Add New Configuration > Shell Script

3. Setup your shell script execution. Make sure to click on Apply after you're done. But don't close it yet.

4. Select Flutter > Run/main.dart > Before Launch > (+)Add > Run Another Configuration

5. Choose your Shell Script configuration

6. Click Apply then click OK. Your configured Shell Script will now run.

Answer 3

In case you'd like to consider something different, I accomplish exactly what you are requesting by using an external build tools. In my case I chose https://fastlane.tools/, which neatly integrates with Flutter, works for Android and iOS and it's open source.