ExactCalculator: Remove long-click to clear from backspace

import android.view.MenuItem;

import android.view.MotionEvent;

import android.view.View;

import android.view.View.OnLongClickListener;

import android.view.ViewAnimationUtils;

import android.view.ViewGroupOverlay;

import android.view.ViewTreeObserver;

import java.text.DecimalFormatSymbols;

public class Calculator extends AppCompatActivity

        implements OnTextSizeChangeListener, OnLongClickListener,

        AlertDialogFragment.OnClickListener, Evaluator.EvaluationListener /* for main result */,

        DragLayout.CloseCallback, DragLayout.DragCallback {

        implements OnTextSizeChangeListener, AlertDialogFragment.OnClickListener,

        Evaluator.EvaluationListener /* for main result */, DragLayout.CloseCallback,

        DragLayout.DragCallback {

    private static final String TAG = "Calculator";

    /**

        mFormulaText.setOnTextSizeChangeListener(this);

        mFormulaText.addTextChangedListener(mFormulaTextWatcher);

        mDeleteButton.setOnLongClickListener(this);

        if (savedInstanceState != null) {

            restoreInstanceState(savedInstanceState);

                ? getString(R.string.desc_formula) : null);

    }

    @Override

    public boolean onLongClick(View view) {

        mCurrentButton = view;

        if (view.getId() == R.id.del) {

            onClear();

            return true;

        }

        return false;

    }

    // Initial evaluation completed successfully.  Initiate display.

    public void onEvaluate(long index, int initDisplayPrec, int msd, int leastDigPos,

            String truncatedWholeNumber) {