checkbox is always unchecked

in the below code i am trying to use a checkbox. but at run time it is never clickable, i mean when i click on the check box nothing happen or change and the checkbox remains always unchecked

why that is happening?

code:

mcbComputations.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (mcbComputations.isChecked()) {

                    mATComputations = new ATComputations();
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
                        mATComputations.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
                    } else {
                        mATComputations.execute();
                    }

                } else {
                    mATComputations.cancel(true);
                }