Android Example Library (JAR) interface using inline Java code and "direct calling"

Discussion in 'Tutorials & Examples' started by Johan Schoeman, Feb 28, 2015.

  1. Johan Schoeman

    Johan Schoeman Expert Licensed User

    Attached project demonstrates two ways to interface with a JAR file:

    1. Using the JavaObject run method "directly"
    2. Making use of inline Java code

    For method 1 you need to make use of
    #AdditionalJar: fiddleAround in the B4A code (see the code)

    For method 2 you need to make use of
    import com.johan.Geometry.Geometry; (see inline Java code)

    com.johan.Geometry is a package name within fiddleAround.Jar
    is a class within package com.johan.Geometry
    and sphereSurface are methods within class Geometry

    Project prints to the project log only.

    Amazing what you can see inside a JAR when using a Java decompiler
    It can make life much simpler when trying to use a/interface with a foreign JAR file.

    fiddleAround.jar and fiddleAround.xml that are used in this example are inside the /files folder of the attached project.

    Attached Files:

  2. Johan Schoeman

    Johan Schoeman Expert Licensed User

    Ooooops - small error inside the code. The last bit of Sub Activity_Create should look like this:

    'Now we are going to call the same methods making use of inline java code
        'This initialization needs to be here and not earlier in Sub Activity_Create
    Dim e As Double = 4
        e = jo.RunMethod(
    Log("ILJ sphereVolume = " & e)
        e = 
        e = jo.RunMethod(
    Log("ILJ sphereSurface = " & e)
  3. Johan Schoeman

    Johan Schoeman Expert Licensed User

    By the way...something unique about using 3 as the radius when calculating the volume and the surface area of a sphere. Another interesting fact about spheres:

    The derivative of the volume (to R) yields the surface area....

    Volume = 4/3 PI R^3
    Surface Area = 4 PI R^2

    JordiCP likes this.
  4. Johan Schoeman

    Johan Schoeman Expert Licensed User

    There is another way to interface with the fiddleAround library when fiddleAround is selected/enabled in the Libs tab of the project.

    Dim sur As B4Ageometry

    e = sur.sphereVolume(4.0)
    Log("Using Library --> sphereVolume = " & e)

    e = sur.sphereSurface(4.0)
    Log("Using Library --> sphereSurface = " & e)

    See additional code added to the attached project. Wow! B4A is flexible delux....!

    Attached Files:

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