Unable to link native library in OpenCV Android sample

Question

I have OpenCV code (c++), which I want to use in Android. To do this I have to use Android NDK. I downloaded OpenCV package for Android development (ver. 2.4.0) and did all steps from that manual. Basic samples (Java API only) run without problems. Sample #3 (Tutorial 3 (Advanced) - Add Native OpenCV) builds from ndk-builder correctly. But always got exception when I'm trying to run/debug it on device from eclipse: ``` Exception Ljava/lang/UnsatisfiedLinkError; thrown while initializing Lorg/opencv/samples/tutorial3/Sample3View; ``` In this line: ``` System.loadLibrary("native_sample"); ``` Here's full logcat log: ``` 05-31 23:41:45.976: W/ActivityThread(9708): Application org.opencv.samples.tutorial3 is waiting for the debugger on port 8100... 05-31 23:41:45.983: I/System.out(9708): Sending WAIT chunk 05-31 23:41:45.983: I/dalvikvm(9708): Debugger is active 05-31 23:41:46.179: I/System.out(9708): Debugger has connected 05-31 23:41:46.179: I/System.out(9708): waiting for debugger to s…

Accepted Answer

Whoohoo!

Finally I found solution for this problem by myself!

I decided to debug line:

```
System.loadLibrary("native_sample");
```

To do this I downloaded android source code from Android-SDK and then attached source folder (/opt/android-sdk-linux/sources/android-15) to my project. After this I found that error was:

```
Cannot load library: link_image[1936]:    37 could not load needed library 'libopencv_java.so' for 'libhello-jni.so' (load_library[1091]: Library 'libopencv_java.so' not found)
```

And really this library is not in `lib` directory. I don't know why but `ndk-build` ignored it. So i decided to copy and load it manualy. For this I copied `libopencv_java.so` from `/opt/OpenCV-2.4.0/libs/armeabi-v7a` and also edited java code:

```
static {
    System.loadLibrary("opencv_java"); //load opencv_java lib
    System.loadLibrary("native_sample");
}
```

Actually similar problems are:

- Can not load Opencv libraries in necessitas

- Android OpenCV: cannot dlopen camera wrapper library

From second solution I found that I can load libraries using dlopen, but I haven't tried it yet.

So I will write simple bash-script that will do it (just copy) for myself.

Thanks to all.

Unable to link native library in OpenCV Android sample

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