Blackberry OS version

If I develop Blackberry application for OS version 6.0, will the application be compatible with OS version 4.5?开发者_运维知识库 If not, is there some way to port the application easily?

If you develop against a specific SDK (eg 6.0) your application will only be deployable to devices that use the matching OS version (6.0 in this case).

In order to develop applications that specifically target different OS versions, you must build separate deployable binaries for each version. Alternatively, you can build for the lowest common denominator -- if you want to support OS 4.5, build for 4.5 and your app will run (though not always gracefully) on all later BB OS versions.

Two open source projects that you can use for examples are BBSSH and LogicMail.

Neither of these uses preprocessor directives, however both take slightly different approaches to managing multiple target OS's; which solution is more appropriate is best determined by your own needs. Both use ant-based builds; and I think both target from OS 4.5 to 6.0. (Older versions of LogicMail target back to 4.1 I believe)

Build scripts can be found here:

• BBSSH SVN (build.xml,build-impl.xml, build.properties)
• LogicMail SVN (build.xml, build.properties)

Both projects can also be looked to for specific methods of handling things like utilizing features introduced in later OS versions seamlessly to your users -- either providing a custom implementation prior for earlier versions, or disabling the functionality as is appropriate.

Finally a quick note: if you continue to not accept valid answers, you'll soon find that people are less willing to answer you.

Try to use "Preprocessor Directives" to support multiple blackberry devices.

I m not 100% sure but probably not, because version 6.0 uses newer libraries.But try develope in lower version os and it will run at higher version.

hope it helps Wblade

For an example of a quality open source project that supports many different BB OS versions, check out LogicMail.

The ant build.xml loads platform-specific classes based on the target:

<if><isset property="jde460.home"/><then>
  <fileset id="bb460_fileset" dir="..">
    <include .../>
      ...

As far as I can tell, this project does not rely on the preprocessor.