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rscottm edited this page Oct 5, 2011 · 38 revisions

Talk for the SF Bay Area JRuby Meetup

Introduction to Ruboto and Android

  • 3 ways to do Ruby on Android

    • Rhodes: Open source Ruby-based framework for cross-platform app development
    • Scripting Layer 4 Android: Simplified API for various scripting languages (including JRuby)
    • Ruboto: Goal - Make JRuby a first-class development language for Android

  • Basics of Android

    • Linux kernel, Dalvik VM
    • Activity - Visual component, roughly one screen
    • Service - Background process
    • Others - BroadcastReceiver and ContentProvider
    • Intent - "I want to do something" abstraction layer
    • Manifest - Informs system about activities, services, permissions, etc.

  • Challenges

    • Mobile hardware limitations
    • Dalvik VM - different byte code, stack limits
    • Passing control for callbacks to scripts
    • Excess components of JRuby
    • Android resource framework

  • Basics of Ruboto

    • Ruboto IRB - App for running scripts
    • Ruboto Core - Generates apps (set up callbacks)
    • Shared
      • Core package shared on device
      • ruboto.rb - Device script encapsulating JRuby/Android intaraction

Demo, Demo, Demo

  • Ruboto IRB

    • Webrick server (demos use of stdlib, notification, service)

      • Standard demo script to obtain remote access: demo-irb-server.rb

      • Extend demo to get access to demo scripts. Note: this assumes a subdirectory called "demo" that I added to contain the demo scripts, also uses SyntaxHighlighter 3.0.83.

        if $server
  class DemoListServlet < HTTPServlet::AbstractServlet
    def list_page
      %Q[
        <html>
          <body>
            <h2>Demos</h2>
            #{yield}
          </body>
        </html>
      ]
    end

    def do_GET(req, resp)
      resp.content_type = "text/html"
      resp.body = list_page do
        Dir.glob("demo/*.rb").sort.map do |i|
          unless File.directory?(i)
            $server.mount("/#{i}", DemoServlet, i)
            "<a href='/#{i}'>#{i.split('.')[1].split('-').map(&:capitalize).join(' ')}</a><br/>"
          end
        end.join
      end
    end

    def do_POST(req, resp)
      do_GET(req, resp)
    end
  end

  class DemoServlet < HTTPServlet::AbstractServlet
    def body(name="untitled.rb", script="")
      %Q[
        <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
        <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
          <head>
            <script type="text/javascript" src="/demo/shCore.js"></script>
            <script type="text/javascript" src="/demo/shBrushRuby.js"></script>
            <link type="text/css" rel="stylesheet" href="/demo/shCoreDefault.css"/>
            <script type="text/javascript">SyntaxHighlighter.all();</script>
          </head>
          <body style="background: white; font-family: Helvetica">
            <h1>#{name.split('.')[1].split('-').map(&:capitalize).join(' ')}</h1>

            <pre class="brush: ruby; toolbar: false; auto-links: false #{name.split('.').length > 3 ? ('; highlight: ' + name.split('.')[2].split('-').map(&:to_i).inspect) : ''}">#{HTMLUtils.escape(script)}</pre>
            <form action='/' method='post'>
              <input type='submit' value='Eval' />
              <br/>
              <textarea id='code' name='code' rows='1' cols='1'>#{HTMLUtils.escape(script)}</textarea>
            </form>
          </body>
        </html>
      ]
    end

    def do_GET(req, resp)
      resp.content_type = "text/html"
      name = @options[0] || "untitled.rb"
      script = File.exists?(name) ? IO.read(name) : ""
      resp.body = body(name, script)
    end
  end

  $server.mount("/demos", DemoListServlet, nil)
  puts "Demos mounted: http://#{ip_address}:#{SERVER_PORT}/demos"
else
  puts "Mount failed: No server running"
end

    • Intents: Opening 3rd-party apps

      • Camera

        $activity.startActivity(
    Java::android.content.Intent.new(
        Java::android.provider.MediaStore::ACTION_IMAGE_CAPTURE))

      • Browser

        java_import "android.content.Intent"
java_import "android.net.Uri"

$activity.startActivity(Intent.new(Intent::ACTION_VIEW, Uri.parse("http://ruboto.org")))

      • Map

        java_import "android.content.Intent"
java_import "android.net.Uri"

$activity.startActivity(
  Intent.new(
    Intent::ACTION_VIEW, 
    Uri.parse("geo:0,0?q=engine+yard+san+francisco")
  )
)

    • Activity:

      • Domo Arigato, Mr. Ruboto (basic ruboto activity)

        require 'ruboto/activity'

java_import "android.view.Gravity"
java_import "android.widget.TextView"

$activity.start_ruboto_activity "$hello_world" do
  setTitle "Domo Arigato"

  def on_create(bundle)
    tv = TextView.new(self)
    tv.text = "Domo Arigato"
    tv.text_size = 64
    tv.gravity = (Gravity::CENTER_HORIZONTAL | Gravity::CENTER_VERTICAL)
    tv.on_click_listener = proc{|view| view.text = "Mr. Ruboto"}

    self.content_view = tv
  end
end

      • Domo Arigato, Mr. Ruboto version 2 (use of widgets)

        require 'ruboto/activity'
require 'ruboto/widget'

java_import "android.view.Gravity"

ruboto_import_widgets :TextView, :LinearLayout

$activity.start_ruboto_activity "$hello_world" do
  setTitle "Domo Arigato"

  def domo_text_view
    text_view:layout => {:width= => :fill_parent, :height= => :fill_parent, :weight= => 1.0},
              :text => "Domo Arigato",
              :text_size => 48,
              :gravity => (Gravity::CENTER_HORIZONTAL | Gravity::CENTER_VERTICAL),
              :on_click_listener => (proc do |view| 
                view.text = ("Mr. Ruboto" == view.text ? "Domo Arigato" : "Mr. Ruboto")
              end)
  end

  def on_create(bundle)
    self.content_view =
      linear_layout(:orientation => :vertical) do
        linear_layout(:layout => {:width= => :fill_parent, :height= => :fill_parent, :weight= => 1.0}) do
          domo_text_view
          domo_text_view
        end
        linear_layout(:layout => {:width= => :fill_parent, :height= => :fill_parent, :weight= => 1.0}) do
          domo_text_view
          domo_text_view
        end
      end
  end
end

      • Camera/Picture (implements interface), standard demo-camera.rb

        • Adding camera click mount to server

          if $server
  $server.mount_proc('/click') do |req, resp| 
    f = $activity.take_picture
    sleep 2 # wait for picture to be written to the file 
    resp.content_type = "image/jpg"
    resp.body = IO.read f
  end
end

      • Open GL (implements interface, shows open GL) demo-opengl.rb

    • Accessing device features

      • Sensors

        java_import "android.content.Intent"
java_import "android.net.Uri"
java_import "android.location.LocationManager"
java_import "android.content.Context"

l = $activity.getSystemService(Context::LOCATION_SERVICE).
                 getLastKnownLocation(LocationManager::NETWORK_PROVIDER)

$activity.startActivity(
  Intent.new(
    Intent::ACTION_VIEW, 
    Uri.parse("geo:#{l.latitude},#{l.longitude}")
  )
)

      • Voice input

        require 'ruboto/activity'
require 'ruboto/util/toast'

java_import "android.speech.RecognizerIntent"
java_import "android.content.Intent"
java_import "android.net.Uri"

$activity.start_ruboto_activity "$speech_demo" do
  intent = Intent.new(RecognizerIntent::ACTION_RECOGNIZE_SPEECH)
  intent.putExtra(RecognizerIntent::EXTRA_LANGUAGE_MODEL,
                  RecognizerIntent::LANGUAGE_MODEL_FREE_FORM)
  intent.putExtra(RecognizerIntent::EXTRA_PROMPT, "Speech recognition demo")
  startActivityForResult(intent, 1)

  def on_activity_result(requestCode, resultCode, data)
    if resultCode == Activity::RESULT_OK
      results = data.get_string_array_list_extra(RecognizerIntent::EXTRA_RESULTS)
      puts results.join("\n")
      startActivity(Intent.new(Intent::ACTION_VIEW, 
          Uri.parse("geo:0,0?q=" + results[0].gsub(" ", "+"))))
    end
    finish
  end
end

    • Multiple Activities: "One Script to Rule Them All" (create a script to list and run our demos)

      require "ruboto.rb"
java_import "android.app.AlertDialog"

$main_binding = self.instance_eval{binding}

def launch_list(context, title, list, &block)
  ruboto_import_widgets :ListView

  context.start_ruboto_activity "$list" do
    setTitle title
    @list = list
    @block = block
    def on_create(bundle)
        self.content_view = list_view :list => @list, 
                              :on_item_click_listener => proc{|av, v, p, i| @block.call(@list, p)}
    end
  end
end

def show_demo(context, file, name)
  java_import "android.view.Gravity"
  ruboto_import_widgets :EditText, :LinearLayout, :Button

  context.start_ruboto_activity "$demo" do
    getWindow.setSoftInputMode(
         android.view.WindowManager::LayoutParams::SOFT_INPUT_STATE_VISIBLE | 
         android.view.WindowManager::LayoutParams::SOFT_INPUT_ADJUST_RESIZE)

    setTitle name
    @file = file
    def on_create(bundle)
        self.content_view = 
            linear_layout(:orientation => :vertical) do
                button :text => "Eval", :layout => {:width= => :fill_parent},
                       :on_click_listener => proc{eval_code @tv.text.to_s}
                @tv = edit_text :layout => {:height= => :fill_parent},
                                :text => load_demo(@file),
                                :gravity => Gravity::TOP, 
                                :horizontally_scrolling => true,
                                :text_size => 24
            end
    end
  end
end

def eval_code(code)
  begin
    $main_binding.eval(code)
  rescue => e
      AlertDialog::Builder.new($activity).
        setTitle("Error").
        setMessage(e.backtrace.join("\n")).
        setPositiveButton("Ok", nil).
        create.
        show
  end
end

def load_demo(name)
    rv = ""

    if File.exists?(name)
        rv = IO.read(name)
    else
        buff_size = 0x2000
        buff = Java::byte[buff_size].new

        i = $activity.getAssets.open(name)
        i = java.io.BufferedInputStream.new(i, buff_size)
        x = i.read(buff, 0, buff_size)

        while x != -1
          rv += String.from_java_bytes(x == buff_size ? buff : buff[0..(x-1)])
          x = i.read(buff, 0, buff_size)
        end
    end

    rv
end

# Check file system or read from assets
demo_files = nil
if File.directory?("demo")
  demo_files = Dir.glob("demo/*.rb").sort
else
  demo_files = $activity.getAssets.list("demo").select{|i| i[-3..-1] == ".rb"}.sort.map{|i| "demo/#{i}"}
end
demo_names = demo_files.map{|i| i.split('.')[1].split('-').map(&:capitalize).join(' ')}

launch_list($activity, "Please pick a demo", demo_names) do |list, pos|
  show_demo $list, demo_files[pos], demo_names[pos]
end

  • Ruboto Core

    • Development requirements

      • JDK & Ant
      • Ruby, Rubygems, Rake
      • Android SDK & Platforms
      • Gems: ruboto-core & jruby-jars
      • Path: JDK, Ant, Android, Gems bin

    • Note: To match the version of ruboto.rb in Ruboto IRB v0.6 I have created a fork of ruboto-core. Use this gem.

    • Generating the basic app

      ruboto gen app --package org.rubyandroid.demo.jruby_meetup_demo --target=android-12  --min-sdk=android-7
cd jruby_meetup_demo 
rake debug

    • Modify to hold our demo app

      • Copy demo scripts to assets

      • Add About Dialog script as first demo

        require 'ruboto/activity'
require 'ruboto/widget'

ruboto_import_widgets :ScrollView, :TextView

$activity.start_ruboto_dialog "$about" do
  setTitle "About The JRuby Meetup Demo"

  def on_create(bundle)
    self.content_view =
      scroll_view do
        tv = $activity.text_view :padding => [5,5,5,5],
                                 :text => @message,
                                 :text_size => 18,
                                 :text_color => Java::android.graphics.Color::WHITE
        Java::android.text.util::Linkify.addLinks(tv, Java::android.text.util::Linkify::ALL)
      end
  end

@message = %Q[This is a demo of Ruboto (JRuby on Android) created by Scott Moyer for the SF Bay Area JRuby Meetup (September 22, 2011). It consists of a series of demo scripts that you can view and run. For more information:

Wiki of demo:
https://github.com/ruboto/ruboto-core/wiki/Talk%3A-SF-Bay-Area-JRuby-Meetup-%28September-22%2C-2011%29

Meetup:
http://www.meetup.com/SF-Bay-Area-JRuby-Meetup

Ruboto Community:
http://www.ruboto.org

JRuby:
http://jruby.org

Android Development:
http://developer.android.com]
end

      • Generate callback interfaces

        ruboto gen interface android.view.SurfaceHolder.Callback --name RubotoSurfaceHolderCallback
ruboto gen interface android.opengl.GLSurfaceView.Renderer --name RubotoGLSurfaceViewRenderer

      • Request permissions through AndroidManifes.xml

        <uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<uses-permission android:name="android.permission.CAMERA"/>

      • Tell the activities to manage their own orientation changes in AndroidManifes.xml

        android:configChanges="orientation"

    • Create keystore to sign the app for release onto the Market

      keytool -genkey -v -keystore meetup.keystore  -alias meetup -keyalg RSA -keysize 2048 -validity 10000

    • Create a build.properties file to specify the keystore for signing

      key.store=meetup.keystore
key.alias=meetup

    • Build release

      rake release

    • Getting to Market

      • Requires a market account (one time $25)
      • Will need:
        • Screen shots (can use emulator)
        • 512x512 image
        • Description

    • Here's our app

Where From Here?

  • Key outstanding issues
    • Start up speed
    • Stack limitations
    • Size (managed some now)
    • Compiling ruby
    • Generating byte code on the device
    • Handling callbacks from libraries outside of core Android
  • Links
  • Getting involved
    • Use it and let us know what is needed
    • Create demo scripts/tutorials (features, gems)
    • Work on the outstanding problems
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