CODEWITHSUNDEEP
androidgradleandroid-gradle-pluginbuild.gradle
DontPanic
DontPanic

Reputation: 2416

How to invoke a method in Custom Gradle Task?

I am trying to build a custom Gradle Task to perform some app maintenance operations. I would like to pass argument(s) to the task to control operations. To illustrate my dilemma, consider to following two trivial custom task classes:

// Custom task with no arguments
public class HelloClassA extends DefaultTask {
    @TaskAction
    public void printHello()
    {
        println "Hello, World!"
    }
}

// Custom task with one argument
public class HelloClassB extends DefaultTask {
    @TaskAction
    public void printMsg(String msg)
    {
        println msg
    }
}

They are identical except that "A" prints a hard-coded string while "B" accepts a string as an argument.

Class A is used in the following task:

task helloA(type:HelloClassA) { }

and is invoked by, e.g.,

gradlew.bat helloA

It works fine and prints "Hello, World!" to the Build window. However, I can't figure out the syntax is for a task to invoke Class B.

How do I do that? (or am I just way off base trying to do it this way?)

Some rather Strange Things I've noticed...

  1. The name of the method in the classes (e.g., "printHello") seems to be irrelevant: any reasonable name produces identical output (?).
  2. When invoking by gradlew.bat, any unambiguous substring of the task name works the same, e.g., "GRADLEW helloA" or "GRADLEW hell". I guess this is just GRADLE trying to be helpful (?).

Upvotes: 1

Views: 2317

Answers (2)

DontPanic
DontPanic

Reputation: 2416

You can pass an argument(s) directly to a method without using properties. Here's how:

apply plugin: 'com.android.application'

import javax.inject.Inject

abstract class CustomTask extends DefaultTask {
    @Inject
    CustomTask(String message,int number) {
        println "Processing \""+message+"\", "+number    // process args
    }
}

Create task 'mytask' as follows in the android section appending the arguments (which must agree in count and format with the task definitions):

tasks.register( 'mytask', CustomTask, 'Hello, World!', 123 )

Execute 'mytask' by

gradlew.bat mytask

which produces the output

Processing "Hello, World!", 123

Upvotes: 1

Mayur Gajra
Mayur Gajra

Reputation: 9073

You can't directly pass it as an argument to the method. But, if you wish there is a way using @Input annotation.

Following is the example for you use case:

abstract class HelloClassB extends DefaultTask {
    @Input
    abstract Property<String> getMsg()//this is an abstract method to get values

    @TaskAction
    def printMsg() {
        println msg.get() // here we get the value set from task.register
    }
}

// printB is the task name 
tasks.register('printB',HelloClassB) {
    msg = 'Hello B' // here we set the Input value
}

Now in your terminal run: gradlew -q printB

If you want to read more about this then please have a look here: https://docs.gradle.org/current/userguide/custom_tasks.html

Upvotes: 1

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