Question

我正在创建活动日历。我是这个例外java.lang.NumberFormatException: Invalid long: “null”

Utility.java

public class Utility {
    public static ArrayList<String> nameOfEvent = new ArrayList<String>();
    public static ArrayList<String> startDates = new ArrayList<String>();
    public static ArrayList<String> endDates = new ArrayList<String>();
    public static ArrayList<String> descriptions = new ArrayList<String>();

    public static ArrayList<String> readCalendarEvent(Context context) {
        Cursor cursor = context.getContentResolver()
                .query(Uri.parse("content://com.android.calendar/events"),
                        new String[] { "calendar_id", "title", "description",
                                "dtstart", "dtend", "eventLocation" }, null,
                        null, null);
        cursor.moveToFirst();
        // fetching calendars name
        String CNames[] = new String[cursor.getCount()];

        // fetching calendars id
        nameOfEvent.clear();
        startDates.clear();
        endDates.clear();
        descriptions.clear();
        for (int i = 0; i < CNames.length; i++) {

            nameOfEvent.add(cursor.getString(1));
            startDates.add(getDate(Long.parseLong(cursor.getString(3))));
            endDates.add(getDate(Long.parseLong(cursor.getString(4))));
            descriptions.add(cursor.getString(2));
            CNames[i] = cursor.getString(1);
            cursor.moveToNext();

        }
        return nameOfEvent;
    }

    public static String getDate(long milliSeconds) {
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(milliSeconds);
        return formatter.format(calendar.getTime());
    }
}

logcat的

 E/AndroidRuntime(2990): java.lang.NumberFormatException: Invalid long: "null"
 E/AndroidRuntime(2990):    at java.lang.Long.invalidLong(Long.java:125)
 E/AndroidRuntime(2990):    at java.lang.Long.parseLong(Long.java:342)
 E/AndroidRuntime(2990):    at java.lang.Long.parseLong(Long.java:319)
 E/AndroidRuntime(2990):    at com.examples.android.calendar.Utility.readCalendarEvent(Utility.java:36)
 E/AndroidRuntime(2990):    at com.examples.android.calendar.CalendarView$1.run(CalendarView.java:184)

为什么我这样做？任何人帮助我。非常感谢提前..

Answer 1

我相信您的以下陈述会产生错误，

startDates.add(getDate(Long.parseLong(cursor.getString(3))));
endDates.add(getDate(Long.parseLong(cursor.getString(4))));

只需将其更改为以下内容，然后重试。

startDates.add(getDate(Long.parseLong(cursor.getString(3).trim())));
endDates.add(getDate(Long.parseLong(cursor.getString(4).trim())));

您的字段可能包含一个空格，您需要在将其转换为长数据类型之前将其删除。

Answer 2

使用 startDates.add(getDate(cursor.getLong(3))); endDates.add(getDate(cursor.getLong(4)));

而不是

startDates.add(getDate(Long.parseLong(cursor.getString(3))));
     endDates.add(getDate(Long.parseLong(cursor.getString(4))));

java.lang.NumberFormatException：无效的long：“null”

2 个答案: