Android Groovy Shell

Because programming on a smartphone is one of the most badass things to do in your life,
I decided to adapt GroovySh to Android.

This app allows you to write, compile and run Groovy code directly from your smartphone. It also works offline

I strongly recommend using this app with a keyboard adapted for coding such as CodeBoard

Glossary

• Shell Features
  • Shell (general)
  • Shell (managing files)
  • Import Aliases
  • Dependency Management
  • Environments
  • Shell Works
  • Auto Completion
• Libraries
  • hyperpoet
  • grooview
  • charts
  • gmage
  • jsoup (not from me)
• Changelog

Use cases

This is a quick presentation of the Groovy Shell. If you want more details on a section, click on the corresponding link in the glossary.

You can use this app to…

Write Java/Groovy programs

fibonacci = { Integer n ->
  switch (n) {
    case 0:
    case 1:
      return n
    default:
      return fibonacci(n - 1) + fibonacci(n - 2)
  }
}

fibonacci(10)

Import and use your favorite Java libraries

With DexGrape, you can import dependencies from a Maven repository:

import dex
DexGrape.grab('org.apache.commons', 'commons-csv', '1.8')
import org.apache.commons.csv.CSVFormat

f = file("biostats.csv")
Reader reader = f.newReader()
def records = CSVFormat.DEFAULT.withHeader(["Name", "Gender", "Age", "Height", "Weight"] as String[])
        .withFirstRecordAsHeader()
        .parse(reader)
for (record in records) {
  String name = record.get("Name")
  String age = record.get("Age")
  println "$name, $age"
}
reader.close()

Manage your files

cd "Download"
f = file("text.txt")
temp = file("temp.txt")
touch temp
temp.text = f.text
temp << file("appendText.txt")
temp.remove()

This script is absolutely useless, but you get the idea of what you can do with Groovy Shell

Perform network operations

use my http-client library

import hyperpoet // this is an import alias, we'll get on that later
API_URL = "https://jsonplaceholder.typicode.com/"
client = new HttpPoet(url: API_URL, contentType: ContentType.JSON, acceptContentType: ContentType.JSON)
data = client.get("/posts")
println data.title

or perform some web scrapping with jsoup

doc = Jsoup.connect("https://en.wikipedia.org/").get();
newsHeadlines = doc.select("#mp-itn b a");
for (Element headline in newsHeadlines) {
 println String.format("%s\n\t%s", headline.attr("title"), headline.absUrl("href"))
}

Perform modify images directly on your phone

Using Gmage, you can load, modify and display images directly from the shell

import gmage // import alias
gmage = Gmage.from('image.jpg') // actually this method doesn't exists in Gmage library. This method was dynamically added when processing the import alias
gmage.apply(ColorTransformers.duoTone(Color.BLUE))
gmage.apply { Color color -> color & 0xff00ff0f }
gmage.apply(ColorTransformers.replaceColor(Color.BLUE, Color.CLEAR, 0.25f))
def blurred = gmage.blurred(new BoxBlur(BoxBlur.SHARPENING_KERNEL))
def resized = blurred.scaledBy(0.8f, 0.8f)
resized.show() // display the gmage
GmageEncoder.encode(resized, CompressFormat.PNG, new File("output.jpg"))

Create and display charts

I created a wrapper library of MPAndroidChart that allows you to create and display charts.

import chart // more import aliases
import time
chart = new LineChart()
x = []
for (i in (1..10)) x.add(LocalDateTime.now().minusDays(10 - i) as Long)
r = new Random()
y = []
for (i in (1..10)) y.add(r.nextInt(100))
chart.setX(x)
  .setY(y)
  .setTimeUnitX(SECONDS)
  .show()

Process json/xml data

import json
def jsonSlurper = new JsonSlurper()
def object = jsonSlurper.parseText('{ "name": "John Doe" }')
println object.name

def text = '''
    <list>
        <technology>
            <name>Groovy</name>
        </technology>
    </list>
'''

def list = new XmlParser().parseText(text) 

println list.technology.name.text() == 'Groovy' 

Schedule a script to run

I introduced the notion of Shell Works, a script that runs in the background. You can also schedule it to run later, and/or make it periodic. For example, you can write a script to check every day if there are some new articles on your favorite website and notify you about!

You can learn more about it here