How do I read file size with Gradle?

Question

Short version:

How do I read a file's size in bytes with Gradle?

Long version:

My Android build scripts I use with Android Studio need to figure out the size of a resource file in bytes. I'd like that my scripts would do it automatically. How would I do it?

Edit: Added code that I have now:

task getFileSizeFromObb {
    doLast {
        File mainObb = new File("data-android.obb")
        return mainObb.length()
    }
}


android {

    defaultConfig {
        //...
        manifestPlaceholders = [main_obb_size: getFileSizeFromObb.execute()]
        //...
    }
}

This fails with

ERROR: Cause: null value in entry: main_obb_size=null

Gradle is backed by either Groovy or Kotlin/JVM (depending on your impelmentation), and both of those have access to the Java file I/O classes. So, create a `File` that points to the resource and use that to check its length. — CommonsWare, Mar 28 '19 at 13:42
Any tips how? I can't find any tutorials for using Kotlin or Groovy in Gradle. — Habba, Mar 28 '19 at 14:18
Assuming that you have not specifically elected to use Kotlin, your Gradle script *is* Groovy. Gradle is (in part) a DSL that can be used in either Groovy or Kotlin scripts. — CommonsWare, Mar 28 '19 at 14:46

shizhen · Accepted Answer · 2019-03-29T08:35:41.490

2

Try below code to define a gradle/groovy method that returns your file size.

def getFileSizeFromObb() {
    File mainObb = new File("data-android.obb")
    return mainObb.length()
}

and call this method like below:

android {

    defaultConfig {
        //...
        println "===++++ >>>>> size = " + getFileSizeFromObb()
        manifestPlaceholders = [main_obb_size: getFileSizeFromObb()]
        //...
    }
}

I have verified above method, please ensure that your file data-android.obb does exist on the path.

edited Mar 29 '19 at 08:35

answered Mar 29 '19 at 08:30

shizhen

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Thanks, I just figured out that Tasks do not have a return value. So they need to be def as methods. Pretty straightforward after that. – Habba Mar 29 '19 at 09:38

How do I read file size with Gradle?

1 Answers1