让时间不再随系统设置而改变

---

+ (NSString *)timeByTimestamp:(CGFloat)timestamp {

    NSTimeZone *zone = [NSTimeZone defaultTimeZone];

    static NSDateFormatter *formatter =nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        formatter = [[NSDateFormatter alloc] init];
    });
    formatter.locale=[[NSLocale alloc]initWithLocaleIdentifier:@"en_US"];
    [formatter setDateFormat:@"yyyy-MM-dd aa hh:mm"];
    [formatter setTimeZone:zone];

    CGFloat thatTime = timestamp;
    NSDate *thatDate = [NSDate dateWithTimeIntervalSince1970:thatTime];
    NSString *thatString = [formatter stringFromDate:thatDate];
    NSDate *nowDate = [NSDate date];
    CGFloat nowTime = [nowDate timeIntervalSince1970];

    CGFloat spaceTime = nowTime - thatTime;

    if (spaceTime / 60 < 5) {
        return @"刚刚";
    } else if (spaceTime < 60 * 60 * 24) {
        NSString *time = [thatString substringFromIndex:11];
        if ([time hasPrefix:@"PM"]) {
            time = [time stringByReplacingOccurrencesOfString:@"PM" withString:@"下午"];
        }
        if ([time hasPrefix:@"AM"]) {
            time = [time stringByReplacingOccurrencesOfString:@"AM" withString:@"上午"];
        }
        return time;
    } else if (spaceTime < 60 * 60 * 24 * 2) {
        NSString *time = [thatString substringFromIndex:11];
        if ([time hasPrefix:@"PM"]) {
            time = [time stringByReplacingOccurrencesOfString:@"PM" withString:@"昨天下午"];
        }
        if ([time hasPrefix:@"AM"]) {
            time = [time stringByReplacingOccurrencesOfString:@"AM" withString:@"昨天上午"];
        }
        return time;
    } else if (spaceTime < 60 * 60 * 24 * 3) {
        NSString *time = [thatString substringFromIndex:11];
        if ([time hasPrefix:@"PM"]) {
            time = [time stringByReplacingOccurrencesOfString:@"PM" withString:@"前天下午"];
        }
        if ([time hasPrefix:@"AM"]) {
            time = [time stringByReplacingOccurrencesOfString:@"AM" withString:@"前天上午"];
        }
        return time;
    } else if (spaceTime < 60 * 60 * 24 * 4) {
        NSString *time = [thatString substringFromIndex:11];
        if ([time hasPrefix:@"PM"]) {
            time = [time stringByReplacingOccurrencesOfString:@"PM" withString:@"大前天下午"];
        }
        if ([time hasPrefix:@"AM"]) {
            time = [time stringByReplacingOccurrencesOfString:@"AM" withString:@"大前天上午"];
        }
        return time;
    } else if (spaceTime < 60 * 60 * 24 * 365) {
        NSDateFormatter *dateFor = [[NSDateFormatter alloc] init];
        [dateFor setDateFormat:@"M月d日 aa h:mm"];
        [dateFor setTimeZone:zone];
        NSString *time = [dateFor stringFromDate:thatDate];
        time = [time stringByReplacingOccurrencesOfString:@"PM" withString:@"下午"];
        time = [time stringByReplacingOccurrencesOfString:@"AM" withString:@"上午"];
        return time;
    } else {
        NSDateFormatter *dateFor = [[NSDateFormatter alloc] init];
        [dateFor setDateFormat:@"yyyy年M月d日 aa h:mm"];
        [dateFor setTimeZone:zone];
        NSString *time = [dateFor stringFromDate:thatDate];
        time = [time stringByReplacingOccurrencesOfString:@"PM" withString:@"下午"];
        time = [time stringByReplacingOccurrencesOfString:@"AM" withString:@"上午"];
        return time;
    }
}