Link Python GC to Java GC for PythonJavaClass

[tito]

Take a look at this snippet:

class DelayedRunnable(PythonJavaClass):
    __javainterfaces__ = ['java/lang/Runnable']
    def __init__(self, callback, *args, **kwargs):
        super(DelayedRunnable, self).__init__(*args, **kwargs)
        self.callback = callback
    @java_method('()V')
    def run(self):
        self.callback()


handler = Handler(Looper.getMainLooper())
handler.postDelayed(DelayedRunnable(init_receiver), 1000)

The DelayedRunnable() instance will be deleted by Python GC, before java use it.

This is why we can have than kind of weirdness:

I/python  (25412): !! create_proxy_instance() on 1548769344 <__main__.DelayedRunnable object at 0x5c505840>
...
I/python  (25412): !! invoke0() from (1548769344, 1548769344) ('', 'system', 'dock', 'multi')
I/python  (25412):  Exception AttributeError: "'tuple' object has no attribute 'invoke'" in 'jnius.jnius.invoke0' ignored

We need to keep a reference of the DelayedRunnable until the java proxy is really deleted. Keeping a reference is not an issue, detecting when to release it is the issue.

Maybe http://docs.oracle.com/javase/6/docs/api/java/lang/ref/PhantomReference.html could help us, but i'm not sure about how to use it.

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[knappador]

If you find this page, hold a Python reference to whatever Java object is getting destroyed as a workaround. The bug -seems- very difficult, but is easy to get around.