Overview

Volt MX Application Design and Development Guidelines: Application Design Guidelines > Coding Guidelines > iPhone

Foreign Function Interface (FFI) Guidelines

iPhone

• Ensure that the library uses the Object versions of primitive types while writing the wrappers for FFI compatibility. For example, if a number is mentioned in the IDE, the wrapper should accept NSNumber.
• Ensure that namespace for FFI does not clash with the names of the header files in the imported zip file. For example, if the namespace is zxling then there should not be any header file with the name zxling..
• Ensure that any dependent frameworks are added as part of the XCode project configuration before building the XCode project.
• Try to include the .m and .h files (Objective C source code for the third-party library) instead of .a files (binary formats) to avoid build time issues in XCode..a files can still be integrated but the developer might run into build issues which might be hard to debug.

Android

• The Java Class on which the static method is invoked should have a public default constructor:

  public class Foo

  {

  ...public Foo()

  ...{

  .....//default constructor

  ...}

  }

• Ensure that you pass Activity Context Object as the first parameter to the method. A few Android native APIs require access to the Activity class present in the voltmxwidgets.jar file. Make sure that this JAR file is located at <workspace>\temp\<appName>\build\luaandroid\dist\<appName>\libs\ folder.

• Use the static method com.konylabs.android.KonyMain.getActContext() to access the current Activity class.

  

• You can reference any of the APIs that are already present on the device (including voltmxwidgets.jar) in the Java projects.

• Ensure that you do not import these JAR files into Volt MX Iris.

BlackBerry

• The Java Class on which the static method is invoked should have a public default constructor:

  public class Foo

  {

  ...public Foo()

  ...{

  .....//default constructor

  ...}

  }

• The library should not have a main method. The main method is the entry point into the BlackBerry application. Volt MX Iris defines a main method during code generation. Another main method leads to erroneous behavior.

  // Below method should not be part of any class in the library

  public static void main(String[] args)

• Ensure that the Java class files are compiled using the following JAVAC Flags:

  javac -target "1.1" -source "1.2"

• Ensure that resultant JAR file is pre-verified using:

  C:\Program Files\Research In Motion\<JDE FOLDER>>\bin\preverify.exe

  classpath C:\Program Files\Research In Motion\BlackBerry JDE 4.2.1\lib\net_rim_api.jar .jar

• Do not have a class that extends UiApplication interface. If you use a class that extends this interface, the class is not integrated with the IDE and the IDE throws a NoClassDefFoundError. The possible reasons for this error are: 

• JAR file was not pre-verified

• Native Wrapper library refers to a class that extends UiApplication.

• Do not import the net_rim_api.jar file into Volt MX Iris. This JAR file has been provided by BlackBerry only for compiling the BlackBerry Desktop Applications.

  Note: All the methods in all the classes of this JAR file are marked as external (dummy).

• Check the BlackBerry API documentation available at C:\Program Files\Research In Motion\<JDE Version>\docs\api to check if the API used in the library is supported.

• You can reference any of the APIs that are already present on the device (including voltmxwidgets.jar) in the Java projects. But ensure that you do not import these JAR files into Volt MX Iris.
• Check the *rapc.log file (end of the file) located under <workspace>\temp\<appName>\build\luaj2me\blackberry and <workspace>\temp\<appName>\build\luaj2me\blackberry47 if you get the exec returned error 97 error while building an application for BlackBerry in the IDE. This error indicates that the generation of COD file was not successful from the application JAR file.