Re: More loading on Android strangeness

[Per Bothner <per at bothner dot com>]

On 11/20/2014 03:13 AM, Ben Simon wrote:
> On Wed, Nov 19, 2014 at 2:26 PM, Jamison Hope <jrh@theptrgroup.com> wrote:
> I agree.  Any ideas why these errors are being printed out in the log
> vs. being thrown as an exception?  In an ideal world, I'd like to
> catch the exception in the code that calls (load ...) and display it
> to the user.

If it's a "massive stack trace" it could a stack overflow.


> ((current-activity):setContentView
>     (android.widget.TextView (current-activity)
>       text: "Hello World"))
>
> (logi "Ending")
> ; ---------------------------
>
> I get the error in the logs below. I've fiddled around with using (as
> android.app.Activity (current-activity)) to help indicate what type
> the activity is, but that hasn't worked yet.
>
>
> on-create.scm(14167): Starting
> t/sdcard/AppDoh/on-create.scm:8:2: warning - no known slot
> 'setContentView' in java.lang.Object
> t/sdcard/AppDoh/on-create.scm:9:2: caught exception in inliner for
> #<procedure make> - java.lang.NullPointerException
>   gnu.expr.ReferenceExp.<init>(ReferenceExp.java:76)
>   gnu.kawa.android.ViewBuilder.useBuilder(ViewBuilder.scm:17)
>   gnu.kawa.reflect.CompileInvoke.validateNamedInvoke(CompileInvoke.java:249)
>   gnu.kawa.reflect.CompileInvoke.validateApplyInvoke(CompileInvoke.java:151)

This looks like a bug/limitation in the useBuilder meyjpd in ViewBuilder.scm.

First note that the loaded code is "compiled" - though only to an Expression tree,
not all the way to bytecode.

CompileInvoke.validateNamedInvoke is (at compile time) called to process the
  (android.widget.TextView ...)
expression.  It looks for a definition of current-activity in the (lexical) scope.
That becomes the value of activity-decl, which is then passed to the
(gnu.expr.ReferenceExp activity-decl).
It looks like activity-decl is null.

I'm guessing that is because the (require 'android-defs) is not in the same
"module" as the  (android.widget.TextView ...).

A possible work-around is to wrap the entire body in a begin:

(begin
  (require 'android-defs)

  (define (logi . messages)
  (android.util.Log:i "on-create.scm" (apply string-append messages)))

  (logi "Starting")

  ((current-activity):setContentView
   (android.widget.TextView (current-activity)
     text: "Hello World"))

  (logi "Ending")
)

This forces the whole things to be a single "module", which there will
hopefully be a visible declaration for current-activity.

It that works, we can consider replacing the (gnu.expr.ReferenceExp activity-decl)
with something that expands to
  (gnu.kawa.android.utils:current-activity)
That shouldn't be too difficult.
--
	--Per Bothner
per@bothner.com   http://per.bothner.com/