Getting started with GazeSDK: Linking error

[mar]

I am trying to run any Gaze SDK function calls on a new Android app, and I get a linking error, though it appears my call to System.loadLibrary("tobiigazecore-jni") does not raise an error:

java.lang.UnsatisfiedLinkError: No implementation found for void com.tobii.gaze.core.TobiiGazeCoreModuleJNI.swig_module_init() (tried Java_com_tobii_gaze_core_TobiiGazeCoreModuleJNI_swig_1module_1init and Java_com_tobii_gaze_core_TobiiGazeCoreModuleJNI_swig_1module_1init__)

This is the short code I’m trying to run:

 System.loadLibrary("tobiigazecore-jni");
 try {
            String url = Discovery.getConnectedEyeTracker();
            return url;
        } catch (EyeTrackerException e) {
            Log.e(TAG, "getConnectedEyeTrackerUrl failed with error code " + e.errorCode());
        }

Can anyone advise me on how to troubleshoot? Or is there something obvious I should be doing which I’m not doing?

I’ve run nm -C on the .so file, and grep‘ed it for the keyword swig to get the following:

0005e22d T Java_com_tobii_gaze_core_TobiiGazeCoreModuleJNI_swig_1module_1init
00059dcd T SwigDirector_EyeTrackerCallbackHandler::swig_connect_director(_JNIEnv*, _jobject*, _jclass*, bool, bool)
000e42f8 d Java_com_tobii_gaze_core_TobiiGazeCoreModuleJNI_swig_1module_1init::methods
000e9010 d SwigDirector_EyeTrackerCallbackHandler::swig_connect_director(_JNIEnv*, _jobject*, _jclass*, bool, bool)::methods
000e91b0 b SwigDirector_EyeTrackerCallbackHandler::swig_connect_director(_JNIEnv*, _jobject*, _jclass*, bool, bool)::baseclass

There appears to be a match. If that’s the case, why does the call to loadLibrary appear to succeed but the search for Java_com_tobii_gaze_core_TobiiGazeCoreModuleJNI_swig_1module_1init appear to fail?

[Grant [Tobii]]

Hi @marr,

Whilst the method is there, it is not supported for the android platform… perhaps you can try to explain what you are trying to do and we can go from there?

[mar]

@Grant, at this point, I’m just trying to familiarize myself with the interface, but ultimately, I would like to read gaze position data from a connected Android device every 20th of a second or so.

I believe that in order to do that, I need to:

1. instantiate an EyeTracker with the REX’s URL
2. set a callback handler on the tracker
3. establish a connection to the REX

I wished to use Discovery.getConnectedEyeTracker so that I could avoid requiring user input or a hardcoded URL to instantiate the EyeTracker, but if I have understood you, this is not an option on Android.

So I have modified my inchoate code to try new EyeTracker("tobii-ttp://REXDL-030114044623"), but my app still crashes as soon as I run the relevant code. I get an unsatisfied link error, just as in my original post. Here is the more lengthy error from the log:

04-18 12:30:47.348 32282 32282 E AndroidRuntime: FATAL EXCEPTION: main
04-18 12:30:47.348 32282 32282 E AndroidRuntime: Process: edu.ucdavis.auditoryenhancer, PID: 32282
04-18 12:30:47.348 32282 32282 E AndroidRuntime: java.lang.UnsatisfiedLinkError: No implementation found for void com.tobii.gaze.core.TobiiGazeCoreModuleJNI.swig_module_init() (tried Java_com_tobii_gaze_core_TobiiGazeCoreModuleJNI_swig_1module_1init and Java_com_tobii_gaze_core_TobiiGazeCoreModuleJNI_swig_1module_1init__)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at com.tobii.gaze.core.TobiiGazeCoreModuleJNI.swig_module_init(Native Method)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at com.tobii.gaze.core.TobiiGazeCoreModuleJNI.<clinit>(TobiiGazeCoreModuleJNI.java:535)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at com.tobii.gaze.core.EyeTracker.<init>(EyeTracker.java:39)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at edu.ucdavis.auditoryenhancer.eyetracker.EyeTrackerActivity.onCreate(EyeTrackerActivity.java:33)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at android.app.Activity.performCreate(Activity.java:6237)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at android.app.ActivityThread.-wrap11(ActivityThread.java)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at android.os.Handler.dispatchMessage(Handler.java:102)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at android.os.Looper.loop(Looper.java:148)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at android.app.ActivityThread.main(ActivityThread.java:5417)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at java.lang.reflect.Method.invoke(Native Method)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
04-18 12:30:47.348 32282 32282 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

I’m sorry. It looks like I’m not linking the gaze library correctly. Here’s how I set up the libtobiigazecore-jni module, which I try to load with a call to System.loadLibrary("libtobiigazecore-jni"):

include $(CLEAR_VARS)
LOCAL_MODULE := libtobiigazecore-jni
LOCAL_SRC_FILES := ../libs/Tobii/TobiiGazeSdk-JavaApi-1.0.0.86-android-armeabi-v7a/armeabi-v7a/libtobiigazecore-jni.so
include $(BUILD_SHARED_LIBRARY)

[Grant [Tobii]]

Hi @marr,

Thanks for the clarifying that you are using the Rex Device. This is rather an old (and now deprecated) eye tracker so we can only recommend using the version of the Gaze SDK that comes with the device.

That being said, can you clarify if the standard Android sample is able to be built and ran?

[Author]

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