UIDatePicker

//创建UIDatePicker （高度不能修改）
    UIDatePicker *datePicker =[[UIDatePicker alloc]initWithFrame:CGRectMake(0, 0, 200, 800)];
    //设置默认显示时间
    datePicker.date =[NSDate dateWithTimeInterval:-24*60*60 sinceDate:[NSDate date]];
    //设置最小日期
    datePicker.minimumDate =[NSDate dateWithTimeInterval: -24*60*60*3 sinceDate:[NSDate date]];
    //设置最大日期
    datePicker.maximumDate =[NSDate dateWithTimeInterval:24*60*60*3 sinceDate:[NSDate date]];
    //    UIDatePicker 基于UIControl
    [datePicker addTarget:self action:@selector(dateAct:) forControlEvents:UIControlEventValueChanged];
    //日期
    datePicker.datePickerMode =UIDatePickerModeDate;
    //倒计时
    datePicker.datePickerMode =UIDatePickerModeCountDownTimer;
    //时间
    datePicker.datePickerMode =UIDatePickerModeTime;
    //默认时间和日期
    datePicker.datePickerMode =UIDatePickerModeDateAndTime;
    [self.view addSubview:datePicker];
}
//valueChanged时 会调用该方法
- (void)dateAct:(UIDatePicker *)picker{
    NSLog(@"%@",picker.date);

}