我有三個班。 1.Class:`在對象列表(ArrayList)中添加對象!
public class Handler {
private String name;
private String short_name;
private int semester;
private int modul_number;
private String prof;
private int credits;
private double note;
private ArrayList<Handler_date> dates;
public Handler() {
}
public Handler(String _name, String _short_name, int _semester, int _modul_number,
String _prof, int _credits, double _mark) {
this.modul_number=_modul_number;
this.name = _name;
this.short_name = _short_name;
this.semester = _semester;
this.prof = _prof;
this.credits = _credits;
this.note= _mark;
dates = new ArrayList<Handler_date>();
}
public void add_date(String _room, int _time,
String _day) {
Handler_date temp = new Handler_date(_room, _time,
_day);
dates.add(temp);
}`
和2.class(elementClass中):
`public class Handler_date {
private String room;
private int time;
private String day;
public Handler_date() {
}
public Handler_date(String _room, int _time,
String _day) {
this.room = _room;
this.time = _time;
this.day = _day;
}
}
我想添加一個模件,但我得到了dates.add(temp);
我打電話給方法templist.search_modul_number(modulnumber).add_date("room", 1, "monday");
我的處理程序對象被保存在一個額外的ObjectList /類到一個arrayList ... private ArrayList<Handler> handlerlist;
任何一個想法我做錯了什麼?
謝謝!
什麼是NullPointerException的完整堆棧跟蹤? – Jeffrey 2012-02-12 21:10:41