CheckBoxPreference cb1 = new CheckBoxPreference(this);
    CheckBoxPreference cb2 = new CheckBoxPreference(this);

private CheckBoxPreference[] mFilterSubjects = new CheckBoxPreference(this)[24];

private CheckBoxPreference[] mFilterSubjects = new CheckBoxPreference[24];

private CheckBoxPreference[] mFilterSubjects = new CheckBoxPreference[24];

for(int i = 0; i < 24; i++){
    mFilterSubjects[i] = new CheckBoxPreference(this);
}