我有一个数据库表，用户在其中保存了一些字符串。我想比较两个包含日期的字符串和一个字符串之间的差异。更具体地说：两个日期遵循这种格式，例如“2012-10-24 00:00”，数字就像这样“2”。有没有办法在查询中获取两个日期之间的差异？我也尝试将日期格式化为长，但由于整个数据库的大循环，我被迫关闭。先感谢您
mCursor1.moveToFirst();
mCursor1= mDbHelper.fetchTasks();
for(int u=0; u<mCursor2.getCount(); u++){
mCursor1.moveToPosition(u);
long id=mCursor1.getLong(0);
Date Date1 = ConvertToDate(this.mCursor1.getString(5));
Date DateNow = ConvertToDate( current );
Calendar a= DateToCalender (this.mCursor1.getString(5));
Calendar b= DateToCalender(current);
a.add(Calendar.MONTH, 1);
b.add(Calendar.MONTH, 1);
long diff= daysBetween(b,a);
if(dateNotify=="1"&& diff%1==0){
mDbHelper.updateNotification(id,"true");
}
else if(dateNotify=="2"&& diff%2==0){
mDbHelper.updateNotification(id,"true");
}
else if(dateNotify=="3"&& diff%3==0){
mDbHelper.updateNotification(id,"true");
}
else if(dateNotify=="7"&& diff%7==0){
mDbHelper.updateNotification(id,"true");
}
mCursor1.moveToNext();
}
}
/从日期转换为日历/ public Calendar DateToCalender(String str_date){
SimpleDateFormat formatter ;
Date date ;
Calendar cal;
formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm");
try {
date = (Date)formatter.parse(str_date);
cal=Calendar.getInstance();
cal.setTime(date);
} catch (ParseException e) {
e.printStackTrace();
return null;
}
return cal;
}
/*Days difference between two dates*/
public static long daysBetween(Calendar startDate, Calendar endDate) {
Calendar date = (Calendar) startDate.clone();
long daysBetween = 0;
while (date.before(endDate)) {
date.add(Calendar.DAY_OF_MONTH, 1);
daysBetween++;
}
return daysBetween;
}
/*Convert string to Date*/
public Date ConvertToDate(String dateString){
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm");
Date convertedDate;
try {
convertedDate = dateFormat.parse(dateString);
} catch (ParseException e) {
e.printStackTrace();
return null;
}
return convertedDate;
}