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# Base Loader Callback Interface Implementation

class `BaseLoaderCallback`

  Basic implementation of `LoaderCallbackInterface`. Logic of this implementation is well-described by the following scheme:

## Using in Java Activity

There is a very base code snippet implementing the async initialization with `BaseLoaderCallback`. See the “15-puzzle” OpenCV sample for details.

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    public class MyActivity extends Activity implements HelperCallbackInterface
    {
    private BaseLoaderCallback mOpenCVCallBack = new BaseLoaderCallback(this) {
       @Override
       public void onManagerConnected(int status) {
         switch (status) {
           case LoaderCallbackInterface.SUCCESS:
           {
              Log.i(TAG, "OpenCV loaded successfully");
              // Create and set View
              mView = new puzzle15View(mAppContext);
              setContentView(mView);
           } break;
           default:
           {
              super.onManagerConnected(status);
           } break;
         }
       }
    };

    /** Call on every application resume **/
    @Override
    protected void onResume()
    {
        Log.i(TAG, "Called onResume");
        super.onResume();

        Log.i(TAG, "Trying to load OpenCV library");
        if (!OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_6, this, mOpenCVCallBack))
        {
            Log.e(TAG, "Cannot connect to OpenCV Manager");
        }
    }

## Using in Service

Default `BaseLoaderCallback` implementation treats application context as `Activity` and calls `Activity.finish()` method to exit in case of initialization failure. To override this behavior you need to override `finish()` method of `BaseLoaderCallback` class and implement your own finalization method.

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- Ask a question on the Q&A forum.
- If you think something is missing or wrong in the documentation, please file a bug report.

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