Changes

==Goal==

==Goal==

To describe a new Sugar bundle which supports equally Activity software and prepared Content.   

To describe a new Sugar bundle which supports equally Activity software and prepared Content.   

  exec sugar-etext-activity [options] <etext_file>

  exec sugar-etext-activity [options] <etext_file>

===EToys Content Viewer===

===Etoys Content Viewer===

The Sugar EToys Content Viewer is packaged as sugar-etoys-content-viewer.  Package dependences are not known at this time.   

The Sugar Etoys Content Viewer is packaged as sugar-etoys-content-viewer.  Package dependences are not known at this time.   

The purpose of having a separate content viewer for Etoys is that the content viewer wrapper script launches Etoys in a mode which bypasses the home screen, and seamlessly launches into the Etoys content.  [http://activities.sugarlabs.org/en-US/sugar/addon/4054 FreeCell] is an example of this idea.

The purpose of having a separate content viewer for Etoys is that the content viewer wrapper script launches Etoys in a mode which bypasses the home screen, and seamlessly launches into the Etoys content.  [http://activities.sugarlabs.org/en-US/sugar/addon/4054 FreeCell] is an example of this idea.

This package contains some of the source code to the EToys activity, plus the sugar-etoys-activity launcher script.

This package contains some of the source code to the Etoys activity, plus the sugar-etoys-activity launcher script.

EToys-based Unified content bundles are made up of a Squeak VM.  The activity.info file contains the line:

Etoys-based Unified content bundles are made up of a Squeak script or Etoys project.  The activity.info file contains the line:

  exec sugar-etoys-activity [options] <squeak_vm_file>

  exec sugar-etoys-activity [options] <squeak_file>

==Content Viewer implementation==

==Content Viewer implementation==

Content Viewers require very small changes to Sugar.  This is because they are really a special case of Activities.   

Content Viewers require very small changes to Sugar.  This is because they are really a special case of Activities.   

Content viewers are distributed as distro packages.  Their activity files are installed into /usr/share/sugar/activities.  Their wrapper scripts are installed into /usr/bin.  Their activity.info files include a new line "hidden=true" which prevents them from being visible in any of the Home views, which prevents them from being launched directly by the user.

Content viewers are distributed as distro packages.  Their activity class files are installed into /usr/share/sugar/activities.  Their wrapper scripts are installed into /usr/bin.  Their activity.info files include a new line "hidden=true" which prevents them from being visible in any of the Home views, which prevents them from being launched directly by the user.

==Content Viewers and MIME Types==

==Content Viewers and MIME Types==

==Content Viewer based Activities==

==Content Viewer based Activities==

One advantage of Sugar providing the content viewers versus packaging them as individual activities is that they can be extended by developers to create new activities.

Making Sugar provide the content viewers instead of releasing them as individual activities is that they can be extended by developers to create new activities.

For example, the WikiBrowse activity is based on the Browse classes.  If Browse, is not installed, WikiBrowse cannot launch.  With the source code to Browse part of Sugar, web-based activities can be built on top of the Content Viewer classes and extended with additional Python code such as a custom server or PyXPCom code.   

For example, the WikiBrowse activity is based on the Browse classes.  If Browse, is not installed, WikiBrowse cannot launch.  With the source code to Browse part of Sugar, web-based activities can be built on top of the Content Viewer classes and extended with additional Python code such as a custom server or PyXPCom code.   

Or, a Flash developer can develop a game in Flash but use Python to manage the toolbars.  They would package their Python code and SWF file in a Unified bundle, and reference the sugar-swf-activity classes from their Python code.

As another example, the Gmail activity is a customized copy of an older (now broken) version of the Browse source code.  With the content viewer source available, this would no longer be needed.

==Sugar changes==

 

==Implementation==

The primary change to Sugar is that it should gracefully handle failure to find the program specified by the 'exec' line in activity.info, displaying a friendly error message on the launcher screen to the effect of "You do not have the required software to view this content.".

The primary change to Sugar is that it should gracefully handle failure to find the program specified by the 'exec' line in activity.info, displaying a friendly error message on the launcher screen to the effect of "You do not have the required software to view this content.".

There is also the new hidden=true line in activity.info to prevent Content Viewers from appearing in the Home view.

There is also the new hidden=true line in activity.info to prevent Content Viewers from appearing in the Home view.