无法访问活动内的成员对象

Question

为什么我不能访问remTime对象？我得到运行时异常,而我可以访问以相同方式声明的所有其他Activity成员.

public class MainActivity extends Activity {
    ListView lstDayInterval, lstWeekDay, lstMonthDay, lstMonth;
        ...
    RemCalendar remTime;

    @Override
    public void onCreate(Bundle savedInstanceState) {

        ...
        remTime.setToNow();

    }




public class RemCalendar  {

    private Calendar C;

    public RemCalendar() {
        C = Calendar.getInstance();
    }

    public void setToNow() {
        C = Calendar.getInstance();
    }
}

谢谢

Answer 1

你忘了remTime在从RemCalendar类调用方法之前初始化实例.在里面初始化onCreate:

@Override
    public void onCreate(Bundle savedInstanceState) {

        ...
        remTime=new RemCalendar();
        remTime.setToNow();

    }