我想使日历视图，以支持触摸交互。 所以我想建立新的自定义日历视图。 我试图使之间的观点偏移和实际日期值映射功能。

I want to make calendar view in order to support touch interaction. So I'd like to build new custom calendar view. I tried to make mapping function between view offset and real date value.

下面是我的想法： 如果我能计算出周自基准日数（在我的情况，1989年12月31日）， 很容易知道的偏移。 HEIGHT_FOR_WEEK * NUM_OF_WEEK是很简单的计算 要知道确切的偏移量。

Here is my idea: If I can compute the number of weeks since base date(in my case, 1989-12-31), it is easy to know offset. HEIGHT_FOR_WEEK * NUM_OF_WEEK is very simple computation to know exact offset.

我的问题是这样的： 首先我从基准日毫秒值。我设置毫秒 另一个日历对象。我希望从该对象相同的日期。但实际上， 这是不同的日期。

My problem is this: First I got milliseconds value from base date. And I set the milliseconds to another calendar object. I expected same date from that object. But actually it was different date.

mBaseDateInMillis = mBaseDate.getTimeInMillis();
mAnotherDate.setTimeInMillis(mBaseDateInMillis);
/* I expect mBaseDate == mAnotherDate.
 * but it was different.
 */

下面是我的code：

public class CalendarCoordinate {
    public static final long ONEWEEK_IN_MILLISECONDS = 60 * 60 * 24 * 7 * 1000;
    public Calendar mBaseDate = new GregorianCalendar(TimeZone.getTimeZone("GMT"));
    public long mBaseDateInMillis = 0;
    public Calendar mDate = new GregorianCalendar(TimeZone.getTimeZone("GMT"));
    public int  mWeekHeight = 30;

    /**
     * CTOR
     */
    public CalendarCoordinate() {
        /* Base date is 1989-12-31 0, 0, 0
         * It was Sunday and offset 0 will be mapped onto this day.
         */
        mBaseDate.set(Calendar.MILLISECOND, 0);
        mBaseDate.set(1989, 12, 31, 0, 0, 0);
        mBaseDateInMillis = mBaseDate.getTimeInMillis();
        Log.v(TAG, "BaseDate:" + mBaseDate.toString());
    }

    /**
     * Compute DATE from Y-Offset
     * @param yOffset
     * @return
     */
     public Calendar dateFromYOffset(int yOffset) {
        long nthWeeks = yOffset / mWeekHeight;
        long millsSinceBaseDate = nthWeeks * ONEWEEK_IN_MILLISECONDS;
        mDate.clear();
        mDate.set(Calendar.MILLISECOND, 0);
        mDate.setTimeInMillis(mBaseDateInMillis + millsSinceBaseDate);

        /* We SHOULD call to update mDate internal data structure. 
         * Java is really strange for this thing
         **/
        mDate.getTimeInMillis();
        return mDate;
    }

    /**
     * Compute Y-Offset from DATE
     * @param date
     * @return
     */
    public long yOffsetFromDate(Calendar cal) {
        long mills = cal.getTimeInMillis();
        long nthWeeks = (mills - mBaseDateInMillis)/ONEWEEK_IN_MILLISECONDS;
        return nthWeeks * mWeekHeight;
    }
}

有人能帮助我吗？我不是一个很好的Java程序员。

Anybody can help me? I'm not a good Java programmer.

推荐答案

这个说法混淆了我：

/* I expect mBaseDate == mAnotherDate.
 * but it was different.
 */

您实际上是试图通过做比较，以检查是否相等：     如果（mBaseDate == mAnotherDate）{的System.out.println（他们都一样）; }

Are you actually trying to check for equality by doing the comparison: if (mBaseDate == mAnotherDate) { System.out.println("They are the same"); }

如果是这样，您的问题是，你误会了==操作符在Java中是如何工作的。它比较的参考，而不是比较底层对象数据，并且因为这些是不同的对象（具有相同的值），将永远是假的。对于更详细信息，请参见 Java的注意事项比较符。

If so, your issue is that you are misunderstanding how the "==" operator works in Java. It compares references, rather than comparing the underlying object data, and since these are different objects (with the same values) that will always be false. For a lot more details, see the Java Notes on comparison operators.

此外，这些行看起来真的很可疑的对我说：

Also, these lines look really suspicious to me:

/* We SHOULD call to update mDate internal data structure. 
* Java is really strange for this thing
**/
mDate.getTimeInMillis();

如果机器人有一个要求，你做的这个错误，我真的很惊讶，但我想一切皆有可能。什么样的问题，你有没有这个电话吗？

I would really be surprised if Android had a bug requiring you to do this, but I guess anything is possible. What kind of problems do you have without this call?