《简单的自定义DropDatePicker》-- UIPopoverController 和 代理 以及 Block 实现。

最近做项目为了方便项目使用，自定义的空间 写的比较粗糙。欢迎大家批评指正。
以上为在项目中的实际应用

//  DropDownDatePicker.h
//  DropDownDatePickerDemo
//
//  Created by HRP on 15/3/25.
//  Copyright (c) 2015年 HRP. All rights reserved.
//

#import <UIKit/UIKit.h>
typedef NS_ENUM(NSInteger, DropDownDatePickerMode)
{
  DropDownDatePickerModeDate,
  DropDownDatePickerModeTime
};

@interface DropDownDatePicker : UIView

- (id)initWithFrame:(CGRect)frame dateMode:(DropDownDatePickerMode)mode;

@property (nonatomic, copy) void(^dateChangeHandler)(NSDate *);

@property (nonatomic, readonly) UILabel         *titleLabel;
@property (nonatomic, readonly) UIBarButtonItem *confrimButton;

@property (nonatomic,strong   ) UIColor         *dateTextColor; //Default is Blue
@property (nonatomic,strong   ) UIFont          *dateTextFont;  //Default is 14.0

@property (nonatomic,strong   ) NSDate          *currentDate;   //Default is [NSDate date]

@property (nonatomic,retain   ) NSDate          *minimumDate;   //Default is nil
@property (nonatomic,retain   ) NSDate          *maximumDate;   //Default is nil

@property (nonatomic,assign   ) NSInteger       minuteInterval;


@end

===== 以下为DropDownDatePicker.m======

//
//  DropDownDatePicker.m
//  DropDownDatePickerDemo
//
//  Created by  HRP on 15/3/25.
//  Copyright (c) 2015年 HRP. All rights reserved.
//

#import "DropDownDatePicker.h"

@protocol HRPDropDownDatePickerControllerDelegate <NSObject>

@required

- (void)datePickerControllerNeedDismiss;
- (void)datePickerControllerDateChanged:(NSDate *)newDate;

@end

@interface HRPDropDownDatePickerController : UIViewController

- (id)initWithDatePickerMode:(DropDownDatePickerMode)mode;

@property (nonatomic) UIPopoverController *popover;

@property (nonatomic,readonly ) UILabel         *titleLable;
@property (nonatomic,readonly ) UIBarButtonItem *confrimButton;
@property (nonatomic,readwrite) NSDate          *currentDate;

@property (nonatomic,weak)id<HRPDropDownDatePickerControllerDelegate> delegate;

@property (nonatomic,retain) NSDate *minimumDate;
@property (nonatomic,retain) NSDate *maxmumDate;
@property (nonatomic)        NSInteger minuteInterval;

@end

@implementation HRPDropDownDatePickerController
{
  DropDownDatePickerMode  _mode;
  UIDatePicker           *_picker;
  NSDate                 *_lastDate;
}

- (id)initWithDatePickerMode:(DropDownDatePickerMode)mode
{
  if (self = [super init])
  {
    _mode = mode;
  }
  return self;
}

- (void)viewDidLoad
{
  _confrimButton = [[UIBarButtonItem alloc] initWithTitle:@"OK"
                                                    style:UIBarButtonItemStyleDone
                                                   target:self action:@selector(dismiss)];
 
  self.navigationItem.rightBarButtonItem = _confrimButton;
 
  _titleLable = [[UILabel alloc] initWithFrame:CGRectMake(0, 10, 70, 30)];
  _titleLable.textColor         = [UIColor blueColor];
  _titleLable.font              = [UIFont systemFontOfSize:17];
  self.navigationItem.titleView = _titleLable;
 
  _picker = [[UIDatePicker alloc] initWithFrame:CGRectMake(0, 0, 250, 200 - 44)];
  _picker.datePickerMode = (_mode == DropDownDatePickerModeDate)?UIDatePickerModeDate:UIDatePickerModeTime;
  [self.view addSubview:_picker];
}

- (void)dismiss
{
  _lastDate = self.currentDate;
 
  if (![self.currentDate isEqual:_lastDate])
  {
    if (_delegate) {
      [_delegate datePickerControllerDateChanged:self.currentDate];
    }
  }
  if (_delegate) {
    [_delegate datePickerControllerNeedDismiss];
  }
}

- (void)setCurrentDate:(NSDate *)currentDate
{
  [_picker setDate:currentDate animated:YES];
}

- (void)setMaxmumDate:(NSDate *)maxmumDate
{
  _picker.maximumDate = maxmumDate;
}

- (void)setMinimumDate:(NSDate *)minimumDate
{
  _picker.minimumDate = minimumDate;
}

- (NSDate *)currentDate
{
  return _picker.date;
}

- (NSDate *)maxmumDate
{
  return _picker.maximumDate;
}

- (NSDate *)minimumDate
{
  return _picker.minimumDate;
}

- (void)setMinuteInterval:(NSInteger)minuteInterval
{
  _picker.minuteInterval = minuteInterval;
}

@end

@interface DropDownDatePicker()
<HRPDropDownDatePickerControllerDelegate>

@end

@implementation DropDownDatePicker
{
  UIButton                        *_button;
  UIPopoverController             *_popover;
  HRPDropDownDatePickerController *_controller;
  DropDownDatePickerMode           _mode;
  BOOL                             _needNotify;
}

- (id)initWithFrame:(CGRect)frame
           dateMode:(DropDownDatePickerMode)mode
{
  self = [super initWithFrame:frame];
  if (self) {
    _needNotify = NO;
    _mode       = mode;
    UIImage *arrowImage = [UIImage imageNamed:@"HZDropDownDatePickerDownArrow"];
    CGRect  imageViewFrame = CGRectMake(CGRectGetWidth(self.bounds) - arrowImage.size.width - 10, 10, arrowImage.size.width, arrowImage.size.height);
    
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:imageViewFrame];
    imageView.image           = arrowImage;
    imageView.backgroundColor = [UIColor redColor];
    [self addSubview:imageView];
    
    _button = [UIButton buttonWithType:UIButtonTypeSystem];
    _button.contentVerticalAlignment = UIControlContentHorizontalAlignmentLeft;
    _button.titleLabel.font          = [UIFont systemFontOfSize:14.0];
    _button.frame                    = self.bounds;
    [_button setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
    
    [_button addTarget:self
                action:@selector(showPopover)
      forControlEvents:UIControlEventTouchUpInside];
    
    [self addSubview:_button];
    
    _controller = [[HRPDropDownDatePickerController alloc] initWithDatePickerMode:mode];
    _controller.delegate = self;
    
    UINavigationController *navi = [[UINavigationController alloc] initWithRootViewController:_controller];
    if (!_popover) {
      _popover = [[UIPopoverController alloc] initWithContentViewController:navi];
      _popover.popoverContentSize = CGSizeMake(250, 200);
    }
    else {
      [_popover setContentViewController:navi];
    }
    self.currentDate = [NSDate date];
  }
  return self;
}

- (UILabel *)titleLabel
{
  return _controller.titleLable;
}

- (NSDate *)currentDate{
  return _controller.currentDate;
}

- (void)setDateTextFont:(UIFont *)dateTextFont
{
  _button.titleLabel.font = dateTextFont;
}

- (UIFont *)dateTextFont
{
  return _button.titleLabel.font;
}

- (void)setDateTextColor:(UIColor *)dateTextColor
{
  [_button setTitleColor:dateTextColor forState:UIControlStateNormal];
}

- (UIColor *)dateTextColor
{
  return [_button titleColorForState:UIControlStateNormal];
}

- (void)setCurrentDate:(NSDate *)currentDate
{
  _controller.currentDate = currentDate;
  _needNotify = NO;
  [self datePickerControllerDateChanged:currentDate];
}

- (void)setMaximumDate:(NSDate *)maximumDate
{
  _controller.maxmumDate = maximumDate;
}

- (NSDate *)maximumDate
{
  return _controller.minimumDate;
}

- (void)setMinimumDate:(NSDate *)minimumDate
{
  _controller.minimumDate = minimumDate;
}

- (NSDate *)minimumDate
{
  return _controller.minimumDate;
}

- (NSInteger)minuteInterval{
  return _controller.minuteInterval;
}

- (void)setMinuteInterval:(NSInteger)minuteInterval{
  _controller.minuteInterval = minuteInterval;
}

-(UIBarButtonItem *)confrimButton{
  return _controller.confrimButton;
}

#pragma mark -
#pragma mark delegate

- (void)datePickerControllerNeedDismiss
{
  [_popover dismissPopoverAnimated:YES];
}

- (void)datePickerControllerDateChanged:(NSDate *)newDate
{
  NSString *dateString;
  NSDateFormatter* formater = [[NSDateFormatter alloc] init];
  if(_mode == DropDownDatePickerModeDate){
    formater.dateFormat = @"yyyy年 MM月 dd日";
  }
  else if(_mode == DropDownDatePickerModeTime){
    formater.dateFormat = @"hh: mm";
  }
 
  dateString = [formater stringFromDate:newDate];
  [_button setTitle:dateString forState:UIControlStateNormal];
 
  if(_dateChangeHandler && _needNotify){
    _dateChangeHandler(newDate);
  }
  _needNotify = YES;
}

#pragma mark Private Methods

- (void)showPopover
{
  CGFloat x = self.bounds.size.width / 2;
  CGFloat y = self.bounds.size.height / 2;
 
  [_popover presentPopoverFromRect:CGRectMake(x, y, 10, 10)
                            inView:_button
          permittedArrowDirections:UIPopoverArrowDirectionAny
                          animated:YES];
}

@end