Camera.open() blocking UI thread

I've looked at all the SO articles I could find on this but none of the solutions work for me.

When called Camera.open(), there is a 3 second (give or take) delay where the UI thread is blocked. I have attempted to put that in a background thread. I'm currently using the solution found here (pasted below) but the 'wait' method is synchronous so it blocks the UI thread too.

What I'm looking to do is load this fragment, show a progress spinner until the camera is good to go, then show the camera on screen, but this delay is killing me and I can't seem to find any really good solution on it.

My fragment:

public class BarcodeFinderFragment extends Fragment implements View.OnClickListener, Camera.AutoFocusCallback, Camera.PreviewCallback {

    private static final String CAMERA_THREAD_NAME = "CAMERA_THREAD_NAME";
    private Camera mCamera;

    private CamViewFinder mPreview;
    private Handler autoFocusHandler;
    private boolean previewing = true;
    private Button noScan;
    private Button noBarcode;
    private FrameLayout preview;
    private BarcodeFinderCallback callBack;
    private ImageScanner scanner;

    private CameraHandlerThread mThread = null;


    private BarcodeFinderCallback dummyCallback = new BarcodeFinderCallback() {
        @Override
        public void onNoScanClicked() {

        }

        @Override
        public void onNoBarcodeClicked() {

        }

        @Override
        public void finishActivity() {

        }

        @Override
        public void setActivityResult(Bundle bundle) {

        }

        @Override
        public void showProgressDialog(boolean showProgress) {

        }
    };

    public static BarcodeFinderFragment newInstance() {
        return new BarcodeFinderFragment();
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        try {
            callBack = (BarcodeFinderActivity) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                    + " must implement OnHeadlineSelectedListener");
        }
    }

    @Override
    public void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);


    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_barcode_finder, container, false);

        noScan = (Button) view.findViewById(R.id.btnNoScan);
        noBarcode = (Button) view.findViewById(R.id.btnNobarcode);
        preview = (FrameLayout) view.findViewById(R.id.cameraPreview);
        noScan.setOnClickListener(this);
        noBarcode.setOnClickListener(this);

        return view;
    }

    @Override
    public void onResume() {
        super.onResume();

        autoFocusHandler = new Handler();

        //Instance barcode scanner
        scanner = new ImageScanner();
        scanner.setConfig(0, Config.X_DENSITY, 3);
        scanner.setConfig(0, Config.Y_DENSITY, 3);

        openCamera();

        mPreview = new CamViewFinder(getActivity(), mCamera, BarcodeFinderFragment.this, BarcodeFinderFragment.this);
        preview.addView(mPreview);
        callBack.showProgressDialog(false);
    }

    private void getCamera() {
        mCamera = null;
        try {
            mCamera = Camera.open();
        } catch (final Exception e) {
            Log.d("BarcodeFinderFragment", e.toString());
        }
    }

    private void openCamera() {
        if (mThread == null)
            mThread = new CameraHandlerThread(CAMERA_THREAD_NAME);

        synchronized (mThread) {
            mThread.openCamera();
        }
    }

    @Override
    public void onPause() {
        super.onPause();
        releaseCamera();
    }

    @Override
    public void onDetach() {
        super.onDetach();

        callBack = dummyCallback;
    }

    private Runnable doAutoFocus() {
        return new Runnable() {
            @Override
            public void run() {
                if (previewing) {
                    mCamera.autoFocus(BarcodeFinderFragment.this);
                }
            }
        };
    }

    private void releaseCamera() {
        if (mCamera != null) {
            previewing = false;
            mCamera.stopPreview();
            mCamera.setPreviewCallback(null);
            mCamera.release();
            mCamera = null;
        }

        callBack.finishActivity();
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btnNoScan:
                callBack.onNoScanClicked();
                break;

            case R.id.btnNobarcode:
                callBack.onNoBarcodeClicked();
                break;
        }
    }

    @Override
    public void onAutoFocus(boolean success, Camera camera) {
        autoFocusHandler.postDelayed(doAutoFocus(), 1000);
    }

    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {

        final Camera.Parameters parameters = camera.getParameters();
        final Camera.Size size = parameters.getPreviewSize();

        final Image barcode = new Image(size.width, size.height, "Y800");
        barcode.setData(data);

        final int result = scanner.scanImage(barcode);

        if (result != 0) {
            previewing = false;
            mCamera.setPreviewCallback(null);
            mCamera.stopPreview();

            final SymbolSet syms = scanner.getResults();
            for (final Symbol sym : syms) {
                final Bundle bundle = new Bundle();
                bundle.putString("result", sym.getData());
                bundle.putString("codeType", "" + sym.getType());

                callBack.setActivityResult(bundle);
            }
        }
    }

    public interface BarcodeFinderCallback {
        void onNoScanClicked();

        void onNoBarcodeClicked();

        void finishActivity();

        void setActivityResult(Bundle bundle);

        void showProgressDialog(boolean showProgress);
    }

    private class CameraHandlerThread extends HandlerThread {

        Handler mHandler = null;

        public CameraHandlerThread(String name) {
            super(name);
            callBack.showProgressDialog(true);
            start();

            mHandler = new Handler(getLooper());
        }

        synchronized void notifyCameraOpened() {
            notify();
        }

        void openCamera() {
            mHandler.post(new Runnable() {
                @Override
                public void run() {
                    getCamera();
                    notifyCameraOpened();
                }
            });

            try {
                wait();
            } catch (InterruptedException e) {
                Log.d("BarcodeFinderFragment", "wait was interrupted");
            }
        }
    }
}

UPDATE

Thanks to MeetTitan, I was able to get this working very smoothly by keeping everything in the background thread and posting to the UI when needed. Here is the working code for anybody who may need it in the future :)

public class BarcodeFinderFragment extends Fragment implements View.OnClickListener {

    private static final String CAMERA_THREAD_NAME = "CAMERA_THREAD_NAME";
    private Camera mCamera;
    private CamViewFinder mPreview;
    private Handler autoFocusHandler;
    private FrameLayout preview;
    private ImageScanner scanner;
    private boolean previewing = true;
    private CameraHandlerThread mThread = null;

    private BarcodeFinderCallback callBack;
    private BarcodeFinderCallback dummyCallback = new BarcodeFinderCallback() {
        @Override
        public void onNoScanClicked() {
        }

        @Override
        public void onNoBarcodeClicked() {
        }

        @Override
        public void finishActivity() {
        }

        @Override
        public void setActivityResult(int resultCode, Bundle bundle) {
        }

        @Override
        public void showProgressDialog(boolean showProgress) {
        }
    };

    public static BarcodeFinderFragment newInstance() {
        return new BarcodeFinderFragment();
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        try {
            callBack = (BarcodeFinderActivity) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()
                    + " must implement BarcodeFinderCallback");
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_barcode_finder, container, false);

        Button noScan = (Button) view.findViewById(R.id.btnNoScan);
        Button noBarcode = (Button) view.findViewById(R.id.btnNobarcode);
        preview = (FrameLayout) view.findViewById(R.id.cameraPreview);
        noScan.setOnClickListener(this);
        noBarcode.setOnClickListener(this);

        return view;
    }

    @Override
    public void onResume() {
        super.onResume();

        autoFocusHandler = new Handler();

        //Instance barcode scanner
        scanner = new ImageScanner();
        scanner.setConfig(0, Config.X_DENSITY, 3);
        scanner.setConfig(0, Config.Y_DENSITY, 3);

        callBack.showProgressDialog(true);
        openCamera();

    }

    private void openCamera() {
        if (mThread == null) {
            try {
                mThread = new CameraHandlerThread(CAMERA_THREAD_NAME);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        synchronized (mThread) {
            mThread.openCamera();
        }
    }

    @Override
    public void onPause() {
        super.onPause();
        releaseCamera();

        if (mThread != null && mThread.isAlive())
            mThread.interrupt();
    }

    @Override
    public void onDetach() {
        super.onDetach();

        callBack = dummyCallback;
    }

    private void releaseCamera() {
        if (mCamera != null) {
            previewing = false;
            mCamera.stopPreview();
            mCamera.setPreviewCallback(null);
            mCamera.release();
            mCamera = null;
        }

        callBack.finishActivity();
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btnNoScan:
                callBack.onNoScanClicked();
                break;

            case R.id.btnNobarcode:
                callBack.onNoBarcodeClicked();
                break;
        }
    }

    public interface BarcodeFinderCallback {
        void onNoScanClicked();

        void onNoBarcodeClicked();

        void finishActivity();

        void setActivityResult(int resultCode, Bundle bundle);

        void showProgressDialog(boolean showProgress);
    }

    private class CameraHandlerThread extends HandlerThread implements Camera.AutoFocusCallback, Camera.PreviewCallback {

        Handler mHandler = null;

        public CameraHandlerThread(String name) throws InterruptedException {
            super(name);
            callBack.showProgressDialog(true);
            start();

            mHandler = new Handler(getLooper());
        }

        void openCamera() {
            mHandler.post(new Runnable() {
                @Override
                public void run() {
                    mCamera = null;
                    try {
                        mCamera = Camera.open();
                    } catch (final Exception e) {
                        Log.d("BarcodeFinderFragment", e.toString());
                        callBack.setActivityResult(Activity.RESULT_CANCELED, null);
                        interrupt();
                    }
                    notifyCameraOpened();

                    getActivity().runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            mPreview = new CamViewFinder(getActivity(), mCamera, CameraHandlerThread.this, CameraHandlerThread.this);
                            preview.addView(mPreview);

                            new Handler().postDelayed(new Runnable() {
                                @Override
                                public void run() {
                                    callBack.showProgressDialog(false);
                                }
                            }, 500);
                        }
                    });
                }
            });
        }

        synchronized void notifyCameraOpened() {
            notify();

        }

        @Override
        public void onAutoFocus(boolean success, Camera camera) {
            autoFocusHandler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    if (previewing) {
                        getActivity().runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                mCamera.autoFocus(CameraHandlerThread.this);
                            }
                        });
                    }
                }
            }, 1000);
        }

        @Override
        public void onPreviewFrame(byte[] data, Camera camera) {

            final Camera.Parameters parameters = camera.getParameters();
            final Camera.Size size = parameters.getPreviewSize();

            final Image barcode = new Image(size.width, size.height, "Y800");
            barcode.setData(data);

            final int result = scanner.scanImage(barcode);

            if (result != 0) {
                previewing = false;
                mCamera.setPreviewCallback(null);
                mCamera.stopPreview();

                final SymbolSet syms = scanner.getResults();
                for (final Symbol sym : syms) {
                    final Bundle bundle = new Bundle();
                    bundle.putString("result", sym.getData());
                    bundle.putString("codeType", "" + sym.getType());

                    getActivity().runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            callBack.setActivityResult(Activity.RESULT_OK, bundle);
                        }
                    });
                }
            }
        }
    }
}

Could you not continue your thread and call groups of ui commands together with the yourContext.runOnUiThread() method? Then you background any blocking code, wait for the camera to be ready, and update the ui from the background thread.

For example:

private class CameraHandlerThread extends ... {
    public void run() {
        getCamera();
        yourContext.runOnUiThread(new Runnable(){
            public void run()
            {
                ...
            }
        });
    }
}

Then you can simply new CameraHandlerThread().start();