我只是想让这个背景消失

这是我的代码

public void selectDate(View view) {
    DialogFragment newFragment = new SelectDateFragment();
    newFragment.show(Master_.fragmentManager,"DatePicker");
}

public void populateSetDate(int year,int month,int day) {


        Birthdate.setText(year + "-" + month + "-" + day);

}

public class SelectDateFragment extends DialogFragment implements
        DatePickerDialog.OnDateSetListener {
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        final Calendar calendar = Calendar.getInstance();
        int yy = calendar.get(Calendar.YEAR);
        int mm = calendar.get(Calendar.MONTH);
        int dd = calendar.get(Calendar.DAY_OF_MONTH);

    DatePickerDialog dialog =new DatePickerDialog(mActivity,R.style.jehadStyle,this,yy,mm,dd);  
    dialog.getDatePicker().setMaxDate(calendar.getTimeInMillis());  

    return dialog ;
    }

    public void onDateSet(DatePicker view,int yy,int mm,int dd) {
        populateSetDate(yy,mm + 1,dd);
    }
}

这是我的风格

<style name="jehadStyle" parent="@android:style/Theme.Holo.Light.Dialog.NoActionBar">
    <item name="android:textColor">@android:color/black</item>

</style>