Java Question Crash at Dim

[Damdu98]

Hello Forum Users,

I tried to imitate Erels Example Lib "FirstLib" from the Tutorial, but when I run the Application, I get the message "The Application MyFTP (Process de.Dominik.MyFTPTest) has stopped unexpectly".

My B4A-Code:

'Activity module
Sub Process_Globals
   Dim fl As FirstLib
End Sub

Sub Globals
End Sub

Sub Activity_Create(FirstTime As Boolean)
   Log(fl.calculate(2, 5))
End Sub

Sub Activity_Resume
End Sub

Sub Activity_Pause (UserClosed As Boolean)
End Sub

My Java-Code:

package de.Dominik.FirstLib;

import anywheresoftware.b4a.BA.ShortName;
import anywheresoftware.b4a.BA.Version;

@ShortName("FirstLib")
@Version(1f)

public class FirstLib {
   /**
    * Multiplicates the first given Parameter with the second
    * @param a: The first multiplication factor
    * @param b: The second multiplication factor
    * @return: The product of both factors
    */
   public int calculate(int a, int b)
   {
      return a*b;
   }   
}

I'm sure you can help me.
Thanks a lot

 

[Gigatron]

Hi i make the same project under eclipse

Import android 8 SDK

Here the source:

package com.gtr.firstlib;


import anywheresoftware.b4a.BA.ShortName;
import anywheresoftware.b4a.BA.Version;

@ShortName("FirstLib")
@Version(1f)

public class Firstlibrary {

   
   

    
      /**
       * Multiplicates the first given Parameter with the second
       * @param a: The first multiplication factor
       * @param b: The second multiplication factor
       * @return: The product of both factors
       */
      public int calculate(int a, int b)
      {
         return a*b;
      }   
   }

After this i ve tested ON B4A ..

With Log(fl.calculate(2,5))... The logcat show 10 .. result..
It's working without problem...

After finish writing code on eclipse:
1 select Firstlib on project explorer
2 Right click and select Export
3 Select jarfile and select Firstlib if not selected
4 Write destination folder on jarfile.... like this H:\Program Files\Anywhere Software\Basic4android\New-Libs\Firstlib.jar
5 select next and next again + finish.
6 Creat xml docfile ... explained at the video..
7 Launch B4A
8 Right Click on right, Referenced Library and REFRESH..
9 Select the new library Firstlib... when it's loaded on your project, you can use it.

I dont know the other way...

 

[Damdu98]

Thanks for your quick reply Gigatron.
I tried it like you said, but nevertheless the application crashes like in my first post.

I I did this way:
1. I created a Java Project named FirstLibrary
2. I added the three librarys to the build path
3. I created a class named FirstLibrary
4. I pasted your code
5. I created the jar-file like you said
6. I created the xml-file like in the video

 

[Damdu98]

In the LogCat messages it seems like the Android-System can not find my package. I think thats the problem... I'm sure I'm doing something wrong :sign0085:
In the attachments are my eclipse project exported as Archive-File, the *.xml and the *.jar that I've created and the unfiltered LogCat.

I have no idea how to solve my problem...

 

[stevel05]

Did you copy the jar and xml to whichever directory you have set as the additional libraries folder in the ide? (Tools/Configure Paths)

 

[Damdu98]

Yes, I have set the additional libraries folder.
It's: "H:\_Programmieren\Android\0_Librarys"

I always copy the *.jar-file and the *.xml-file to this folder, but nevertheless it didn't work...

 

[Erel]

Are you sure that the right jar / xml are referenced? Try changing the version of the library and then do a refresh in the libs folder. Make sure that the version gets updated.

 

[Damdu98]

Are you sure that the right jar / xml are referenced? Try changing the version of the library and then do a refresh in the libs folder. Make sure that the version gets updated.

Thanks Erel, but I have already done this and it works. I changed the Version of the library from 1.1 to 1.2 and after I refreshed the libraries tab the library had the version number 1.20

 

[Erel]

I believe that the problem happens because you are compiling with Java 7 instead of 6.

 

[Damdu98]

I believe that the problem happens because you are compiling with Java 7 instead of 6.

I used Java SDK 7 in eclipse, you're right Erel. I changed to Java 6_29, but it still crashes.
I attached a screenshot of my eclipse Package Explorer and all my referenced librarys, but I think I've referenced the right ones...

 

[Erel]

Can you upload the jar file created with Java 6?

 

[Damdu98]

Here is the Library created with Java 6

 

[Erel]

You are still compiling with Java 7.
You can use the javap tool to find the java version. Major version should be 50.

c:\Program Files (x86)\Java\jdk1.6.0_21\bin>javap -verbose -classpath c:\users\h\desktop de.Dominik.Test.FirstLibrary
Compiled from "FirstLibrary.java"
public class de.Dominik.Test.FirstLibrary extends java.lang.Object
  SourceFile: "FirstLibrary.java"
  RuntimeVisibleAnnotations: length = 0x14
   00 02 00 16 00 01 00 17 73 00 18 00 19 00 01 00
   17 46 00 1A
  minor version: 0
  major version: 51

 

[Damdu98]

You are still compiling with Java 7.
You can use the javap tool to find the java version. Major version should be 50.

Thanks a lot Erel, but how can I change the Javaversion that I'm compiling with?

 

[Erel]

Configure build path - Libraries:

Remove java 7 and add java 6 jre.

 

[Damdu98]

Thanks a lot for your quick answer Erel!! I changed the Library to Java 6 and now it works without problems!! :sign0060: