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Editorial Team
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Asked: 2026-06-16T04:59:22+00:00

Does anyone know how to capture joystick events from the Android NDK? The NDK

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Does anyone know how to capture joystick events from the Android NDK?

The NDK does not contain any APIs to let me extract axis information from an AMotionEvent. (AXIS_X and AXIS_Y are mapped to the pointer (x,y) pair, but I need more than that.) There are Java APIs to do this… but when I’m using the NDK, events aren’t delivered to Java-land, so I simply never receive them.

And I haven’t found any way to turn an NDK AMotionEvent into a Java MotionEvent so that I can pass it through to Java via JNI and extract the information that way.

I absolutely have to get joystick information to my app, but so far I’ve found no way to do so, no matter how evil. Any ideas?

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1 Answer

  1. Editorial Team

    The people at Nvidia Tegra have managed to do this by using an undocumented function call.
    They do an dlopen and a dlsym on libandroid.so to look for AMotionEvent_getAxisValue()

    void* lib = dlopen("libandroid.so",0);
...
s_AMotionEvent_getAxisValue = (float(*)(const AInputEvent*,int32_t axis, size_t pointer_index))
        dlsym(lib,"AMotionEvent_getAxisValue");

    For more information, you should consult nvidias android samples in Tegra Android Development Pack

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