(zdia 10/2011)

The conditions of this feasibility study were

   * Linux Salix based on Slackware 13.37 with Xfce
   * Android emulator with Api 8 (v. 2.2)
   * javac 1.6.0_25
   * Android SDK r14: http://dl.google.com/android/android-sdk_r14-linux.tgz
   * JTcl-2.0.0
   * Apache Ant(TM) version 1.8.2

***Create the projects folders***

Create an Android project with something like:

======none
$ android create project \
    --package tcl.lang \
    --activity JTcl \
    --target 1 \
    --path ~/Projekte/jtcl
======
To get info about your existing existing targets:
======none
$ android list targets
Available Android targets:
id: 1 or "android-8"
     Name: Android 2.2
     Type: Platform
     API level: 8
     Revision: 3
     Skins: WVGA854, WVGA800 (default), QVGA, HVGA, WQVGA432, WQVGA400
======

***Prepare for compilation***

We add an folder ''assets/'' and put as folder ''src/'' the folder ''jtcl-2.0.0/src/main/java/tcl/lang'' of Jtcl into our development directory. We have still to put the ''jtcl-2.0.0/src/main/resources/tcl/lang/library/init.tcl'' file into the ''assets/'' folder. JTcl will need it for initialization. Finally your tree hierarchy should look similar to the following:

======none
|-- AndroidManifest.xml
|-- android
|   |-- bin
|   |   |-- classes
|   |   |-- classes.dex
|   |   `-- jtcl.ap_
|   `-- jtcl.jar
|-- assets
|   `-- init.tcl
|-- bin
|-- build
|-- build.xml
|-- development.txt
|-- jtcl.properties
|-- libs
|-- proguard.cfg
|-- res
|   |-- drawable-hdpi
|   |   `-- icon.png
|   |-- drawable-ldpi
|   |   `-- icon.png
|   |-- drawable-mdpi
|   |   `-- icon.png
|   |-- layout
|   |   `-- main.xml
|   `-- values
|       `-- strings.xml
`-- src
    `-- tcl
        `-- lang
======

***Create the binary***

The file ''jtcl.properties'' will define our local Android environment:

======none
$ cat jtcl.properties
sdk-folder=~/Projekte/jtcl
android-tools=~/Programme/android-sdk-linux_x86/tools
android-platform=~/Programme/android-sdk-linux_x86/platforms/android-8
android-platform-tools=~/Programme/android-sdk-linux_x86/platform-tools
======

The file `Interpr.java` in `src/tcl/lang/` has to be modified to load the `init.tcl` from our `assets/` directory:

======
      // evalResource("/tcl/lang/library/init.tcl");
      evalResource("assets/init.tcl");
======

Then all is ready for ant which will be fed by the following `build.xml`:

======
<?xml version="1.0" encoding="UTF-8"?>

<!--
Inspirations taken from the build.xml found in David Weltons "Hecl for Android":
http://www.hecl.org/
-->

<project name="JTcl for Android" default="help">

  <!-- ====================================================================== -->
  <!-- Build environment properties                                           -->
  <!-- ====================================================================== -->

  <property name="outdir" value="android/bin" />
  <property file="jtcl.properties" />
  <property name="android.build" value="android/bin/classes"/>
  <property name="android-jar" value="${android-platform}/android.jar" />
  <property name="dx" value="${android-platform-tools}/dx" />
  <property name="dex-file" value="classes.dex" />
  <property name="intermediate-dex" value="${outdir}/${dex-file}" />
  <property name="aapt" value="${android-platform-tools}/aapt" />
  <property name="resource-dir" value="res" />
  <property name="asset-dir" value="assets" />
  <property name="srcdir" value="src" />
  <property name="resources-package" value="${outdir}/jtcl.ap_" />

  <!-- ====================================================================== -->
  <!-- Help target                                                            -->
  <!-- ====================================================================== -->

  <target name="help">
    <echo message="Possible targets: compile jar dex aapt"/>
  </target>

  <!-- ====================================================================== -->
  <!-- Dirs target                                                     -->
  <!-- ====================================================================== -->
  
  <target name="dirs">
    <echo>Creating output directories if needed...</echo>
    <mkdir dir="${outdir}"/>
    <mkdir dir="${android.build}"/>
  </target>

  <!-- ====================================================================== -->
  <!-- Compilation target                                                     -->
  <!-- ====================================================================== -->

  <target name="compile" description="Compile the code" depends= "dirs">
    <echo>bootclasspath: ${android-jar}</echo>
    <javac destdir="${android.build}"
           srcdir="src/tcl/lang"
           source="1.5"
           bootclasspath="${android-jar}" >
    </javac>
  </target>
   
  <!-- ====================================================================== -->
  <!-- Jar package target                                                     -->
  <!-- ====================================================================== -->
  
  <target name="jtcl-jar" depends="compile">
    <echo> Building android/jtlc.jar from dir: ${android.build} ...</echo>
    <jar destfile="android/jtcl.jar" basedir="${android.build}">
      <manifest>
        <attribute name="Main-Class" 
                   value="tcl.lang.Shell"/>
      </manifest>
    </jar>
  </target>
   
  <!-- ====================================================================== -->
  <!-- Dex target                                                     -->
  <!-- ====================================================================== -->

  <target name="dex" depends="jtcl-jar">
    <echo>Converting compiled files and external libraries into ${outdir}/${dex-file}...</echo>
    <apply executable="${dx}" failonerror="true" parallel="true">
      <arg value="-JXmx512m" />
      <arg value="--dex" />
      <arg value="--output=${intermediate-dex}" />
      <arg path="android/jtcl.jar" />
      <fileset dir="${android-platform-tools}/lib" includes="*.jar"/>
    </apply>
  </target>
  
  <!-- ====================================================================== -->
  <!-- aapt target                                                  -->
  <!-- ====================================================================== -->

   <!-- 
   Put the project's resources into the output package file.
   We will use the folder assets to store init.tcl. An Android app has only access
   to the application folders, no chance to create a folder: /tcl/lang/library/
    -->
    
  <target name="aapt" depends="dex">
    <echo>Packaging resources and assets...</echo>
    <exec executable="${aapt}" failonerror="true">
      <arg value="package" />
      <arg value="-f" />
      <arg value="-M" />
      <arg value="AndroidManifest.xml" />
      <arg value="-S" />
      <arg value="${resource-dir}" />
      <arg value="-A" />
      <arg value="${asset-dir}" />
      <arg value="-I" />
      <arg value="${android-jar}" />
      <arg value="-F" />
      <arg value="${resources-package}" />
    </exec>
  </target>

  <!-- ====================================================================== -->
  <!-- Cleaning up target                                                     -->
  <!-- ====================================================================== -->

  <target name="clean" description="Clean the output directory">
    <echo>Deleting dir: ${android.build}</echo>
    <delete dir="${outdir}"/>
  </target>
  
</project>
======

***Preparing test***

In the directory `/android/bin` we will find now the executable file `classes.dex` and a file `jtcl.ap_` with the resources compiled in, so we still have to add the executable to our `jtcl.ap_`:


======none
aapt add jtcl.ap_ classes.dex
======


The above mentioned ''assets/init.tcl'' still has to be modified. For the moment we have no tcllib files in our assets folder so we comment out autoloading of tcllib packages:

======
    # set dir resource:/tcl/pkg/tcllib/library
    # source $dir/pkgIndex.tcl
    puts "Note: No tcllib package available"
======

Now ''jtcl.ap_'' is ready for a test:

We push ''jtcl.ap_'' to Android assumed the folder `/data/local/bin` has been already created by use of `adb shell`:

======none
$ adb push jtcl.ap_ /data/local/bin
======

After connection to a running Android device with ''adb shell'' you call JTcl with its entrypoint ''tcl.lang.Shell'':

======none
# dalvikvm -Xbootclasspath:/system/framework/core.jar -classpath /data/local/bin/jtcl.ap_ tcl.lang.Shell 
======

That's it. Sure, you can use this call inside a "Terminal emulator" Android application.

The next steps will be:


   * Try to get access to the Android GUI widgets by using JTcl's java::* commands

   * To make a clean Android JTcl.apk which can be launched by click executing during initialization not only init.tcl but application code, e.g. in myscript.tcl

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