iOS日期時間加減

- (instancetype)initWithTimeInterval:(NSTimeInterval)secsToBeAdded sinceDate:(NSDate *)date;

使用方法

- (NSDate *)nextMiniteDateForBeginDate:(NSDate *)beginDate
{
    NSDate *date = [[NSDate alloc] init];
    
    NSTimeInterval timeInterval = 60; //這個值爲負時，減去一分鐘，爲正數時加上一分鐘
    
    date = [date initWithTimeInterval:timeInterval sinceDate:beginDate];
    
    return date;
}