.m

- (IBAction)buttonStartTimeClicked:(id)sender {
    WSDatePickerView *datePickerView = [[WSDatePickerView alloc] initWithDateStyle:DateStyleShowYearMonthDay scrollToDate:self.startDate CompleteBlock:^(NSDate *date) {
        self.startDate = date;
        self.textFieldStartTime.text = [self format:date];
    }];
    [datePickerView show];
}

- (NSString *)format:(NSDate *)date {
    NSDateFormatter *formatter = [NSDateFormatter new];
    formatter.dateFormat = @"yyyy-MM-dd";
    return [formatter stringFromDate:date];
}