iOS边练边学--UIPickerView和UIDatePicker的简单使用

一、点菜系统练习（UIPickerView）

<1>UIPickerView的常用代理方法介绍

 1 #pragma mark - <UIPickerViewDelegate>
 2 
 3 // 返回指定列的行宽度
 4 - (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component
 5 {
 6     
 7 }
 8 // 返回指定列中行的高度
 9 - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
10 {
11     
12 }
13 
14 // 返回第component列的第row行的字符串
15 - (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
16 {
17     
18 }
19 // 富文本属性，可以描述文字的大小和颜色
20 - (nullable NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component
21 {
22     
23 }
24 // 返回一个UIView 第component列第row行
25 - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view
26 {
27     
28 }
29 // 人为选择第component列第row行之后执行的代码
30 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
31 {
32     
33 }

<2>UIPickerView必须实现的两个数据源方法

 1 #pragma mark - <UIPickerViewDataSource>
 2 
 3 // 告诉pickView有多少列
 4 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
 5 {
 6     return self.foods.count;
 7 }
 8 
 9 // 告诉pickView的component列中有多少行
10 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
11 {
12     return [self.foods[component] count];
13 }

<3>练习代码

 1 #import "ViewController.h"
 2 
 3 @interface ViewController () <UIPickerViewDataSource,UIPickerViewDelegate>
 4 @property (weak, nonatomic) IBOutlet UIPickerView *pickView;
 5 /** 数据集合 */
 6 @property(nonatomic,strong) NSArray *foods;
 7 @property (weak, nonatomic) IBOutlet UILabel *fruitLabel;
 8 @property (weak, nonatomic) IBOutlet UILabel *mainLabel;
 9 @property (weak, nonatomic) IBOutlet UILabel *drinkLabel;
10 
11 @end
12 
13 @implementation ViewController
14 
15 - (void)viewDidLoad {
16     [super viewDidLoad];
17     for (int i = 0; i < self.foods.count; i++) {
18         [self pickerView:self.pickView didSelectRow:0 inComponent:i];
19     }
20     
21 }
22 // 随机
23 - (IBAction)random:(id)sender {
24     for (int i = 0; i <self.foods.count; i++) {
25         int r = arc4random_uniform((int)[self.foods[i] count]);
26         [self.pickView selectRow:r inComponent:i animated:YES];
27         [self pickerView:self.pickView didSelectRow:r inComponent:i];
28     }
29 }
30 
31 // 懒加载数据
32 - (NSArray *)foods
33 {
34     if (_foods == nil) {
35         NSString *path = [[NSBundle mainBundle] pathForResource:@"foods.plist" ofType:nil];
36         _foods = [NSArray arrayWithContentsOfFile:path];
37     }
38     return _foods;
39 }
40 
41 #pragma mark - <UIPickerViewDataSource>
42 
43 // 告诉pickView有多少列
44 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
45 {
46     return self.foods.count;
47 }
48 
49 // 告诉pickView的component列中有多少行
50 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
51 {
52     return [self.foods[component] count];
53 }
54 
55 #pragma mark - <UIPickerViewDelegate>
56 
57 // 返回指定列中行的高度
58 - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
59 {
60     return 60;
61 }
62 
63 // 返回第component列的第row行的字符串
64 - (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
65 {
66     return self.foods[component][row];
67 }
68 
69 // 人为选择第component列第row行之后执行的代码
70 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
71 {
72     switch (component) {
73         case 0:
74             self.fruitLabel.text = self.foods[component][row];
75             break;
76         case 1:
77             self.mainLabel.text = self.foods[component][row];
78             break;
79         case 2:
80             self.drinkLabel.text = self.foods[component][row];
81             break;
82     }
83 }
84 
85 @end
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二、国旗选择练习（pickerView每行都是返回一个自定义控件）

 1 //
 2 //  ViewController.m
 3 //  0322国旗选择
 4 //
 5 //  Created by admin on 16/3/22.
 6 //  Copyright © 2016年 admin. All rights reserved.
 7 //
 8 
 9 #import "ViewController.h"
10 #import "ChaosFlag.h"
11 #import "ChaosFlagView.h"
12 
13 @interface ViewController () <UIPickerViewDataSource,UIPickerViewDelegate>
14 /** 数据模型集合 */
15 @property(nonatomic,strong) NSMutableArray *flags;
16 @property (weak, nonatomic) IBOutlet UIPickerView *pickView;
17 
18 @end
19 
20 @implementation ViewController
21 
22 - (void)viewDidLoad {
23     [super viewDidLoad];
24     _pickView.delegate = self;
25     _pickView.dataSource = self;
26 }
27 - (NSMutableArray *)flags
28 {
29     if (_flags == nil) {
30         NSString *path = [[NSBundle mainBundle] pathForResource:@"flags.plist" ofType:nil];
31         NSArray *dicArray = [NSArray arrayWithContentsOfFile:path];
32         NSMutableArray *arr = [NSMutableArray array];
33         for (NSDictionary *dict in dicArray) {
34             ChaosFlag *flag = [ChaosFlag flagWithDict:dict];
35             [arr addObject:flag];
36         }
37         _flags = arr;
38     }
39     return _flags;
40 }
41 
42 #pragma mark - <UIPickerViewDataSource>
43 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
44 {
45     return self.flags.count;
46 }
47 
48 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
49 {
50     return 1;
51 }
52 
53 #pragma mark - 代理方法
54 - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
55 {
56     // 加载xib
57     ChaosFlagView *flagView = [[NSBundle mainBundle] loadNibNamed:@"ChaosFlagView" owner:nil options:nil][0];
58     ChaosFlag *flag = self.flags[row];
59     flagView.flag = flag;
60     return flagView;
61 }
62 - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
63 {
64     return 70;
65 }
66 @end
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三、生日选择，省市二级联动

  1 //
  2 //  ViewController.m
  3 //  0323-生日城市选择器
  4 //
  5 //  Created by admin on 16/3/23.
  6 //  Copyright © 2016年 admin. All rights reserved.
  7 //
  8 
  9 #import "ViewController.h"
 10 #import "ChaosProvince.h"
 11 
 12 @interface ViewController () <UITextFieldDelegate,UIPickerViewDataSource,UIPickerViewDelegate>
 13 @property (weak, nonatomic) IBOutlet UITextField *birthdayLabel;
 14 @property (weak, nonatomic) IBOutlet UITextField *cityLabel;
 15 
 16 /** 数据集合 */
 17 @property(nonatomic,strong) NSMutableArray *provinces;
 18 
 19 /** datePicker */
 20 @property(nonatomic,strong) UIDatePicker *datePicker;
 21 /** pickView */
 22 @property(nonatomic,strong) UIPickerView *pickView;
 23 /** 选中的省会索引，用来保存上一次选择的省索引，防止同时拖拽省和市时报错 */
 24 @property(nonatomic,assign) NSInteger proIndex;
 25 @end
 26 
 27 @implementation ViewController
 28 
 29 // 重写get方法，实现懒加载
 30 - (NSMutableArray *)provinces
 31 {
 32     if (_provinces == nil) {
 33         // 初始化数据模型，必须要实例化对象！国旗选择的练习中没有实例化，数据出不来，找了老半天！
 34         _provinces = [NSMutableArray array];
 35         NSString *path = [[NSBundle mainBundle] pathForResource:@"provinces.plist" ofType:nil];
 36         NSArray *dicArray = [NSArray arrayWithContentsOfFile:path];
 37         for (NSDictionary *dict in dicArray) {
 38             ChaosProvince *province = [ChaosProvince provinceWithDict:dict];
 39             [_provinces addObject:province];
 40         }
 41     }
 42     return _provinces;
 43 }
 44 
 45 - (void)viewDidLoad {
 46     [super viewDidLoad];
 47     
 48     _cityLabel.delegate = self;
 49     
 50     _birthdayLabel.delegate = self;
 51     [self setBirthdayInputView];
 52     [self setCitiesInputView];
 53 }
 54 /** 给文本框设置时间选择器的方法 */
 55 - (void)setBirthdayInputView
 56 {
 57     // 给生日文本框设置datePicker
 58     _datePicker = [[UIDatePicker alloc] init];
 59     // 设置时间选择器的语言 zh--中国
 60     _datePicker.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"zh"];
 61     // 设置时间选择器显示的时间格式
 62     _datePicker.datePickerMode = UIDatePickerModeDate;
 63     _birthdayLabel.inputView = _datePicker;
 64     // 想要监听一个控件，没有delegate，就找addTarget方法（这个的前提是控件继承自UIControl）
 65     [_datePicker addTarget:self action:@selector(dateChange:) forControlEvents:UIControlEventValueChanged];
 66 }
 67 /** 监听时间选择器改变的方法 */
 68 - (void)dateChange:(UIDatePicker *)datePicker
 69 {
 70     // 取出时间
 71     NSDate *date = datePicker.date;
 72     // NSDate与NSString之间的转换
 73     NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
 74     formatter.dateFormat =@"yyyy-MM-dd";
 75     NSString *time = [formatter stringFromDate:date];
 76     _birthdayLabel.text = time;
 77 }
 78 
 79 /** 给城市文本框设置选择器的方法 */
 80 - (void)setCitiesInputView
 81 {
 82     _pickView = [[UIPickerView alloc] init];
 83     _pickView.delegate = self;
 84     _pickView.dataSource = self;
 85     _cityLabel.inputView = _pickView;
 86 }
 87 
 88 #pragma mark - pickView数据源方法
 89 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
 90 {
 91     if (component == 0) { // 省的个数
 92         return self.provinces.count;
 93     } else { // 省对应的城市
 94         ChaosProvince *province = self.provinces[self.proIndex];
 95         return province.cities.count;
 96     }
 97 }
 98 
 99 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
100 {
101     return 2; // 两列
102 }
103 
104 #pragma mark - pickerView代理方法
105 - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
106 {
107     if (component == 0) { // 省
108         ChaosProvince *province = self.provinces[row];
109         return province.name;
110     }
111     else // 城市
112     {
113         // 根据省的索引获取对应的城市
114         ChaosProvince *province = self.provinces[self.proIndex];
115         return province.cities[row];
116     }
117 }
118 
119 // 滚动pickerView就调用
120 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
121 {
122     if (component == 0) { // 选择省,刷新相应的城市
123         [pickerView reloadComponent:1];
124         // 记录当前选中的省会索引
125         self.proIndex = [pickerView selectedRowInComponent:0];
126     }
127     // 显示到文本框中
128     
129     // 选中的省
130     ChaosProvince *province = self.provinces[self.proIndex];
131     
132     // 选中的城市
133     NSInteger cityIndex = [pickerView selectedRowInComponent:1];
134     self.cityLabel.text = [NSString stringWithFormat:@"%@ %@",province.name,province.cities[cityIndex]];
135     
136 }
137 
138 #pragma mark - <UITextFieldDelegate>
139 // 文本框开始编辑的时候执行的方法
140 - (void)textFieldDidBeginEditing:(UITextField *)textField
141 {
142     if (textField == self.birthdayLabel) { //生日文本
143         
144         [self dateChange:_datePicker];
145     } else if (textField == self.cityLabel) { // 城市文本
146         [self pickerView:self.pickView didSelectRow:0 inComponent:0];
147     }
148 }
149 
150 // 是否允许在范围内改变字符
151 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
152 {
153     return NO;
154 }
155 @end
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原文地址：https://www.cnblogs.com/gchlcc/p/5313040.html