Crash Problem！

[JamesLiAndroid]

You need to use a Theme.AppCompat theme (or descendant) with this activity

When I use the component in my project, I have got this Error message!

So I have found the code and located the error at the following code:

else if (v == mTextViewQuantity) {
if (!quantityDialog) return;

        if (mTextViewClickListener != null) {
            mTextViewClickListener.onClick(v);
            return;
        }
        // Crash at this line!
        AlertDialog.Builder builder = new AlertDialog.Builder(getContext());
        builder.setTitle(labelDialogTitle);

        final View inflate = LayoutInflater.from(getContext()).inflate(R.layout.qv_dialog_changequantity, null, false);
        final EditText et = (EditText) inflate.findViewById(R.id.qv_et_change_qty);
        et.setText(String.valueOf(quantity));

        builder.setView(inflate);
        builder.setPositiveButton(labelPositiveButton, null);
        final AlertDialog dialog = builder.show();
        dialog.getButton(AlertDialog.BUTTON_POSITIVE).setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                String newQuantity = et.getText().toString();
                if (isValidNumber(newQuantity)) {
                    int intNewQuantity = Integer.parseInt(newQuantity);
                    Log.d(VIEW_LOG_TAG, "newQuantity " + intNewQuantity + " max " + maxQuantity);
                    if (intNewQuantity > maxQuantity) {
                        Toast.makeText(getContext(), "Maximum quantity allowed is " + maxQuantity, Toast.LENGTH_LONG).show();
                    } else if (intNewQuantity < minQuantity) {
                        Toast.makeText(getContext(), "Minimum quantity allowed is " + minQuantity, Toast.LENGTH_LONG).show();
                    } else {
                        setQuantity(intNewQuantity);
                        hideKeyboard(et);
                        dialog.dismiss();
                    }

                } else {
                    Toast.makeText(getContext(), "Enter valid number", Toast.LENGTH_LONG).show();
                }
            }
        });
    } 

getContext() should be replaced by getActivity(). Currently I have to note the code to solve this problem!