How to control the task execute order in Android studio's build.gradle?

Question

I'm using Android Studio 4.1 and Gradle 6.7.1

(Note that the "mergeReleaseAssets" is not my custom task, it is part of the system tasks, and I don't know where to find the definition of "mergeReleaseAssets")

I want to set the task "mergeReleaseAssets" to be executed after "myTask" as below:

...
> Task :app:myTask
...
(no matter how many tasks in the middle should be ok)
...
> Task :app:mergeReleaseAssets
...

The task definition in the build.gradle:

...
task myTask {
    doLast {
        println String.format("put something in the assets")
    }
}
tasks.withType(JavaCompile) { t -> t.finalizedBy myTask }
...

When building the project by clicking Menubar -> "Build" -> "Rebuild Project", the task execute order is not always the same, it seems the tasks are executed in parallel.

The build output for the first time:

Executing tasks: [clean, :app:assembleRelease] in project /home/testproject

> Task :clean UP-TO-DATE
> Task :app:clean UP-TO-DATE
> Task :app:preBuild UP-TO-DATE
> Task :app:preReleaseBuild UP-TO-DATE
> Task :app:compileReleaseAidl NO-SOURCE
> Task :app:compileReleaseRenderscript NO-SOURCE
> Task :app:generateReleaseBuildConfig
> Task :app:checkReleaseAarMetadata
> Task :app:generateReleaseResValues
> Task :app:generateReleaseResources
> Task :app:createReleaseCompatibleScreenManifests
> Task :app:extractDeepLinksRelease
> Task :app:processReleaseMainManifest
> Task :app:processReleaseManifest
> Task :app:processReleaseManifestForPackage
> Task :app:mergeReleaseResources
> Task :app:processReleaseResources
> Task :app:mergeReleaseNativeDebugMetadata NO-SOURCE
> Task :app:mergeReleaseShaders
> Task :app:javaPreCompileRelease

> Task :app:compileReleaseJavaWithJavac
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

> Task :app:myTask
> Task :app:compileReleaseSources
> Task :app:lintVitalRelease
> Task :app:compileReleaseShaders NO-SOURCE
> Task :app:generateReleaseAssets UP-TO-DATE
> Task :app:mergeReleaseAssets
> Task :app:compressReleaseAssets
> Task :app:dexBuilderRelease
> Task :app:checkReleaseDuplicateClasses
> Task :app:processReleaseJavaRes NO-SOURCE
> Task :app:collectReleaseDependencies
> Task :app:sdkReleaseDependencyData
> Task :app:mergeReleaseJniLibFolders
> Task :app:mergeReleaseNativeLibs
> Task :app:stripReleaseDebugSymbols NO-SOURCE
> Task :app:validateSigningRelease
> Task :app:mergeReleaseJavaResource
> Task :app:desugarReleaseFileDependencies
> Task :app:mergeExtDexRelease
> Task :app:mergeDexRelease
> Task :app:packageRelease
> Task :app:assembleRelease

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.7.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD SUCCESSFUL in 2m 0s
32 actionable tasks: 30 executed, 2 up-to-date

Build Analyzer results available

The build output for the second time:

Executing tasks: [clean, :app:assembleRelease] in project /home/testproject

> Task :clean UP-TO-DATE
> Task :app:clean UP-TO-DATE
> Task :app:preBuild UP-TO-DATE
> Task :app:preReleaseBuild UP-TO-DATE
> Task :app:compileReleaseAidl NO-SOURCE
> Task :app:compileReleaseRenderscript NO-SOURCE
> Task :app:generateReleaseBuildConfig
> Task :app:checkReleaseAarMetadata
> Task :app:generateReleaseResValues
> Task :app:generateReleaseResources
> Task :app:javaPreCompileRelease
> Task :app:createReleaseCompatibleScreenManifests
> Task :app:extractDeepLinksRelease
> Task :app:processReleaseMainManifest
> Task :app:processReleaseManifest
> Task :app:processReleaseManifestForPackage
> Task :app:mergeReleaseNativeDebugMetadata NO-SOURCE
> Task :app:mergeReleaseShaders
> Task :app:compileReleaseShaders NO-SOURCE
> Task :app:generateReleaseAssets UP-TO-DATE
> Task :app:mergeReleaseAssets
> Task :app:compressReleaseAssets
> Task :app:checkReleaseDuplicateClasses
> Task :app:processReleaseJavaRes NO-SOURCE
> Task :app:mergeReleaseResources
> Task :app:processReleaseResources
> Task :app:mergeReleaseJavaResource

> Task :app:compileReleaseJavaWithJavac
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
Note: Some input files use unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

> Task :app:desugarReleaseFileDependencies
> Task :app:myTask
> Task :app:compileReleaseSources
> Task :app:lintVitalRelease
> Task :app:dexBuilderRelease
> Task :app:collectReleaseDependencies
> Task :app:sdkReleaseDependencyData
> Task :app:mergeReleaseJniLibFolders
> Task :app:validateSigningRelease
> Task :app:mergeReleaseNativeLibs
> Task :app:stripReleaseDebugSymbols NO-SOURCE
> Task :app:mergeExtDexRelease
> Task :app:mergeDexRelease
> Task :app:packageRelease
> Task :app:assembleRelease

Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
Use '--warning-mode all' to show the individual deprecation warnings.
See https://docs.gradle.org/6.7.1/userguide/command_line_interface.html#sec:command_line_warnings

BUILD SUCCESSFUL in 1m 54s
32 actionable tasks: 30 executed, 2 up-to-date

Build Analyzer results available

As you can see, at the first time, the order is "myTask" ->... -> "mergeReleaseAssets". But the second time, it changed to "mergeReleaseAssets" ->... -> "myTask".

And then, I try to set the task dependency in the build.gradle:

project.getTasks().getByName("mergeReleaseAssets").dependsOn(myTask)
//This also not work
//project.getTasks().getByName(":app:mergeReleaseAssets").dependsOn(myTask)

But Android studio shows error:

Task with name "mergeReleaseAssets" not found in project ':app'

//Or this error if using ":app:mergeReleaseAssets":
Task with name ":app:mergeReleaseAssets" not found in project ':app'

Please help, thanks.

Answer 1

The problem is that mergeReleaseAssets task is dynamically created, so you cannot reference it directly in your build.gradle script.

One solution is to use the Project.afterEvaluate lifecycle hook as described here

project.afterEvaluate{ 
    // at this stage, task 'mergeReleaseAssets' has been declare, you can reference it to perform additional configuration
    project.getTasks().getByName("mergeReleaseAssets").dependsOn(myTask) 
}