I'm running into an issue with reverse bindings similar to this.
My project structure is like:
mobile/
└── pkg
└── example
├── android
│ └── javatest.go
└── testmobile.go
*testmobile.go:*
package example
import (
"mobile/pkg/example/android"
)
func SystemCurrentTimeMillis() int64 {
return android.SystemCurrentTimeMillis()
}
*android.go:*
package android
import (
"Java/java/lang/Float"
"Java/java/lang/System"
)
func SystemCurrentTimeMillis() int64 {
return System.CurrentTimeMillis()
}
func FloatMin() float32 {
return Float.MIN_VALUE
}
When I run gomobile bind on the top-level example package, it fails:
mobile/pkg/example/android/javatest.go:4:2: could not import
Java/java/lang/Float (cannot find package "Java/java/lang/Float" in any of:
If I run gomobile on the android directory, it works. Is it expected that
the above imports should work, or does gomobile bind only work on one
package?
Thanks,
-Kelly
On Thursday, April 25, 2019 at 6:43:19 PM UTC-4, Mark Bauermeister wrote:
>
> Ok. I fixed it.
>
> For anybody interested, here's how I solved it.
>
> On the Go side, I extended my exported function by adding "ctx
> content.Context" as a parameter (i e "func Hello(ctx content.Context).
> On the Java side, I'm then passing the mobile context as follows (this is
> a React Native app, so it's bound to different from regular Android apps):
>
> Context ctx = getReactApplicationContext();
> Mobile.hello(ctx);
>
>
> I can then access the application context from the Go side.
>
> Now one thing that would be interesting still is whether/how I can reverse
> bind "com.facebook.react.bridge.ReactContextBaseJavaModule" on the Go side
> directly,
> so I can call "getReactApplicationContext()" directly from the Go side
> rather than pass the context in from Java.
>
> I know there's "-classpath" but how does it actually work for external
> Java libraries?
>
> On Wednesday, 24 April 2019 15:27:31 UTC+2, Mark Bauermeister wrote:
>>
>> Yea. Turns out that was indeed the issue. I tried accessing a method that
>> didn't actually exist.
>>
>> Unfortunately, your code doesn't work either. It leads to a segmentation
>> violation/nil pointer error.
>> I suspect one needs to somehow get the right context from the Java side.
>> Question is how.
>>
>> I already tried an OnCreate override func, but that one is somehow never
>> called.
>>
>> On Wednesday, 24 April 2019 15:08:02 UTC+2, ma...@eliasnaur.com wrote:
>>>
>>>
>>>
>>> On Wednesday, April 24, 2019 at 2:34:34 PM UTC+2, Mark Bauermeister
>>> wrote:
>>>>
>>>> I'm currently experimenting with Gomobile Reverse Bindings (my hope is
>>>> to eventually be able to call getFilesDir(), so I can save my SQLite3 DB
>>>> on
>>>> mobile) and it is, quite literally, driving me insane.
>>>> I've followed the sparse information available, was able to
>>>> successfully work with 'import "Java/java/lang/System" and call
>>>> "System.currentTimeMillis()".
>>>>
>>>> Now I'm trying to import "Java/android/content" and it fails outright,
>>>> stating that the package "Java/android/content" cannot be found.
>>>>
>>>> What is the correct import path for Android packages, or is there
>>>> something else I need to do that I'm missing?
>>>>
>>>
>>> Note that reverse binding packages will only be generated if you use a
>>> type from it; importing is unfortunately not enough.
>>>
>>> Perhaps
>>>
>>> import "Java/android/content"
>>>
>>> var ctx content.Context
>>> ctx.GetFilesDir()
>>>
>>> is enough to get further.
>>>
>>> The reverse bindings are very fickle, sorry.
>>>
>>> - elias
>>>
>>
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