Apple开发_判断相隔一天

• 需求情景：每日签到弹框，三方登录绑手机提示，及其他身份信息每日提示一次等。

+ (BOOL)ApartOneDayMore {
	//相隔至少一天
	NSDate *lastDate = [[NSUserDefaults standardUserDefaults] objectForKey:@"signInEveryDayLastDate"];
	NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
	[formatter setDateFormat:@"dd"];

	NSString *lastDayStr = [formatter stringFromDate:lastDate];
	NSString *nowDayStr = [formatter stringFromDate:[NSDate date]];

	//一天有24*24*60秒，大于秒数就是隔天，小于时判断day数，不同也是隔天.返回true
	if ([[NSUserDefaults standardUserDefaults] objectForKey:@"signInEveryDayLastDate"]) {
		if (([NSDate date].timeIntervalSince1970-lastDate.timeIntervalSince1970)>24*24*60) {
			[[NSUserDefaults standardUserDefaults] setObject:[NSDate date] forKey:@"signInEveryDayLastDate"];
			return true;
		} 
		else if(nowDayStr.intValue!=lastDayStr.intValue) {
			[[NSUserDefaults standardUserDefaults] setObject:[NSDate date] forKey:@"signInEveryDayLastDate"];
			return true;
		}
		return false;
	}
	//否则,不存在这个字段，说明新装的，返回true
	[[NSUserDefaults standardUserDefaults] setObject:[NSDate date] forKey:@"signInEveryDayLastDate"];

	return true;
}