NSDate API
获取当前时间
获取时间戳
创建间隔指定时间戳的Date
// 获取昨天
NSTimeInterval time = 24 * 60 * 60;
NSDate *date = [NSDate dateWithTimeIntervalSinceNow: -time];
NSLog(@"%@", date);
// 获取昨天
NSTimeInterval time = 24 * 60 * 60;
NSDate *date = [NSDate dateWithTimeIntervalSinceNow: -time];
NSLog(@"%@", date);