[mono-android] java binding library

[Atsushi Eno]

Hello,

On 2012/06/21 10:05, Wally McClure wrote:
> I'm working on an example of using the java binding library.  I wanted 
> to use a fairly well known java library, so a friend told me to use 
> the commons-math jar library.  Ok, sounds good to me.  I plug this 
> into a MfA java binding library, and of course, it generates a bunch 
> of errors.  This is actually good.  Now, I need to go through and fix 
> these errors as noted here: 
> http://docs.xamarin.com/android/tutorials/Binding_a_Java_Library_%28.jar%29

This kind of Java-vs-C# mismatch always occurs and bites us. There are 
common patterns of troubles. We have some listed (I have to say, that's 
not very up to date though ...) :
http://docs.xamarin.com/android/tutorials/Binding_a_Java_Library_%28.jar%29#Troublshooting_Bindings

>
> Some of the errors that I am getting are:
> Error    1    'Gamma': member names cannot be the same as their 
> enclosing type    C:\Projects\MonoAndroidAppDev\New in 
> 4.2\Projects\ExampleJavaBindings\BindingLibrary\obj\Debug\generated\src\Org.Apache.Commons.Math3.Special.Gamma.cs    
> 12    23    BindingLibrary

We convert Java names from camelCase to PascalCase and that results in 
this kind of problem. Either the member or the type name has to be 
renamed via metadata fixup, e.g.

<attr path="/api/package[@name=...]/class[@name=...]" 
name="managedName">GanmaType</attr>

> Error    2    The type or namespace name 'FirstMoment' does not exist 
> in the namespace 'Org.Apache.Commons.Math3.Stat.Descriptive.Moment' 
> (are you missing an assembly reference?)    
> C:\Projects\MonoAndroidAppDev\New in 
> 4.2\Projects\ExampleJavaBindings\BindingLibrary\obj\Debug\generated\src\Org.Apache.Commons.Math3.Stat.Descriptive.Moment.Mean.cs    
> 30    70    BindingLibrary
>
The troubleshooting section in our site (mentioned above) contains "The 
binding .dll builds but misses some Java types" row. It contains a 
couple of common patterns, which may give you the answer.

> Error    5    Type 
> 'Org.Apache.Commons.Math3.Stat.Clustering.EuclideanIntegerPoint' 
> already defines a member called 
> 'GetCentroidOf_Ljava_util_Collection_Handler' with the same parameter 
> types    C:\Projects\MonoAndroidAppDev\New in 
> 4.2\Projects\ExampleJavaBindings\BindingLibrary\obj\Debug\generated\src\Org.Apache.Commons.Math3.Stat.Clustering.EuclideanIntegerPoint.cs    
> 90    19    BindingLibrary
>

The only possibility I can think of is some multiple-methods-to-events 
conversion conflict case as Miljenko mentioned. Any other reason is 
possible though.

> Error    29    The name 'Handle' does not exist in the current 
> context    C:\Projects\MonoAndroidAppDev\New in 
> 4.2\Projects\ExampleJavaBindings\BindingLibrary\obj\Debug\generated\src\Org.Apache.Commons.Math3.Stat.Descriptive.Moment.SecondMoment.cs    
> 23    22    BindingLibrary
>
> Error    33    The name 'SetHandle' does not exist in the current 
> context    C:\Projects\MonoAndroidAppDev\New in 
> 4.2\Projects\ExampleJavaBindings\BindingLibrary\obj\Debug\generated\src\Org.Apache.Commons.Math3.Stat.Descriptive.Moment.SecondMoment.cs    
> 51    5    BindingLibrary
>

I wonder if this type involves "handle" member in the Java library. 
That's what we haven't hit yet, but Handle is (as you would know) a 
special member from Java.Lang.Object and hence should exist in almost 
all types. In that case, this name conflict has to be again resolved by 
metadata xml fixup.

> Error    35    'object' does not contain a constructor that takes 2 
> arguments    C:\Projects\MonoAndroidAppDev\New in 
> 4.2\Projects\ExampleJavaBindings\BindingLibrary\obj\Debug\generated\src\Org.Apache.Commons.Math3.Stat.Descriptive.Moment.SecondMoment.cs    
> 62    28    BindingLibrary
>

Maybe this is due to other compilation error that caused type resolution 
failure and thus C# compiler tries to lookup the member from 
System.Object. This would change after you resolved other issues.

Atsushi Eno

> I'm wondering what the proper step is to go about fixing them.  Should 
> I go through the code and manually fix this up?  Is there something in 
> the various transform files I should do?  As much assistance as I can 
> get in minute detail would be helpful.
>
> Wally
>
>
>
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