UIPickerView

1.UIPickView什么时候用？

通常在注册模块，当用户需要选择一些东西的时候，比如说城市，往往
弹出一个PickerView给他们选择。

UIPickView常见用法,演示实例程序

1> 独立的，没有任何关系 => 菜单系统。
2> 相关联的，下一列和第一列有联系=> 省会城市选择
3> 图文并帽， => 国旗选择

4.UIDatePicker什么时候用？
当用户选择日期的时候，一般弹出一个UIDatePicker给用户选择

 //
 //  ViewController.m
 //  01-点餐系统
 //
 //  Created by xiaomage on 15/6/9.
 //  Copyright (c) 2015年 xiaomage. All rights reserved.
 //

 #import "ViewController.h"

 @interface ViewController ()<UIPickerViewDelegate,UIPickerViewDataSource>

 @property (weak, nonatomic) IBOutlet UIPickerView *pickerView;

 @end

 @implementation ViewController

 - (void)viewDidLoad {

     [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.
   //设置代理方法方式如下，还有拖线，
     self.pickerView.delegate = self;

 }

 // 返回pickerView有多少列
 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
 {
     return ;
 }

 // 返回第component列有多少行
 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
 {
     return ;
 }

 #pragma mark - 代理
 // 返回第component列的每一行的行高
 - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
 {
     return 80.0;
 }

 // 返回第component列第row行的标题
 - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
 {
     return @"a";
 }

 // NSAttributedString富文本属性: 可以描述文字大小和颜色
 //- (NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component NS_AVAILABLE_IOS(6_0); // attributed title is favored if both methods are implemented

 // 总结：如果同时实现返回字符串和view的方法，返回UIView的优先级比较高
 // 返回第component列第row行的View
 //- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
 //{
 //    UIView *v = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 60, 60)];
 //
 //    v.backgroundColor = [UIColor redColor];
 //
 //    return v;
 //}

 // 选中第component第row的时候调用
 // __func__： 返回当前方法在哪个类里面调用
 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
 {
     NSLog(@"%s---%ld-%ld",__func__,component,row);
 }

 @end

 //
 //  ViewController.m
 //  01-点餐系统
 //
 //  Created by xiaomage on 15/6/9.
 //  Copyright (c) 2015年 xiaomage. All rights reserved.
 //

 #import "ViewController.h"

 // 分屏:cmd + option + return

 // 退出分屏：cmd + return

 @interface ViewController ()<UIPickerViewDelegate,UIPickerViewDataSource>
 @property (weak, nonatomic) IBOutlet UILabel *frultLabel;
 @property (weak, nonatomic) IBOutlet UILabel *mainLabel;
 @property (weak, nonatomic) IBOutlet UILabel *drinkLabel;

 @property (weak, nonatomic) IBOutlet UIPickerView *pickerView;

 @property (nonatomic, strong) NSArray *foods;

 @end

 @implementation ViewController

 // 点击随机的时候调用
 - (IBAction)random:(UIButton *)sender {

     // pickerView每一列随机选中一行

     // 随机选中的文字展示到label

     // cmd + option + [ 代码上跳
     // cmd + [ 代码左移
     for (int i = ; i < ; i++) {

         // 假设让第0列随机选中一行
         // 取出第0列的行数
         NSInteger count = [self.foods[i] count];

         int random = arc4random_uniform((u_int32_t)count);
         // 不会触发代理的选中方法
         [_pickerView selectRow:random inComponent:i animated:YES];

         // 主动给label赋值
         [self pickerView:nil didSelectRow:random inComponent:i];
     }

 }

 - (NSArray *)foods
 {
     if (_foods == nil) {

         // 加载Pilst文件
        NSString *filePath = [[NSBundle mainBundle] pathForResource:@"foods.plist" ofType:nil];

         // 大数组：pickerView有多少列
         _foods = [NSArray arrayWithContentsOfFile:filePath];

     }

     return _foods;
 }

 - (void)viewDidLoad {

     [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.

     self.pickerView.delegate = self;

     // 初始化label标题

     for (int i = ; i < ; i++) {

         [self pickerView:nil didSelectRow: inComponent:i];

     }

 }
 // 返回pickerView有多少列
 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
 {
     return self.foods.count;
 }

 // 返回第component列有多少行
 - (NSInteger)r :(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
 {
     return [self.foods[component] count];
 }

 // 返回第component列第row行的标题
 - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
 {
     return self.foods[component][row];
 }

 - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
 {
     return ;
 }

 // 给label赋值
 // 选中第component列第row行的时候调用
 // 注意：这个方法必须用户主动拖动pickerView，才会调用
 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
 {

     switch (component) {
         case :
             // 设置水果
             _frultLabel.text = self.foods[component][row];
             break;
         case :
             // 设置主食
             _mainLabel.text = self.foods[component][row];
             break;
         case :
             // 设置饮料
             _drinkLabel.text = self.foods[component][row];
             break;
     }

 }

 @end

pickerView返回一个view

 //
 //  ViewController.m
 //  03-国旗选择
 //
 //  Created by xiaomage on 15/6/9.
 //  Copyright (c) 2015年 xiaomage. All rights reserved.
 //

 #import "ViewController.h"

 #import "XMGSubFlag.h"

 #import "XMGFlagView.h"

 @interface ViewController ()<UIPickerViewDataSource,UIPickerViewDelegate>
 @property (weak, nonatomic) IBOutlet UIPickerView *pickerView;

 @property (nonatomic, strong) NSMutableArray *flags;

 @end

 @implementation ViewController

 //读取plist中的数据封装为模型
 - (NSMutableArray *)flags
 {
     if (_flags == nil) {

         // 装flag模型
         _flags = [NSMutableArray array];

         // 加载plist
         NSString *filePath = [[NSBundle mainBundle] pathForResource:@"flags.plist" ofType:nil];

         NSArray *arr = [NSArray arrayWithContentsOfFile:filePath];

         for (NSDictionary *dict in arr) {
             // 字典转模型
             XMGFlag *flag = [XMGFlag flageWithDict:dict];

             [_flags addObject:flag];

         }
     }
     return _flags;
 }

 - (void)viewDidLoad {
     [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.

     _pickerView.dataSource = self;

     _pickerView.delegate = self;

 }

 //数据源方法，返回列数
 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
 {
     return ;
 }
 //读取模型数组返回列有多少行
 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
 {

     return self.flags.count;
 }
 //代理方法 返回一个view
 - (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
 {
 //xib获取view,传入模型
     XMGFlagView *flagView = [[NSBundle mainBundle] loadNibNamed:@"XMGFlagView" owner:nil options:nil][];

     // 取出对应的模型
     XMGFlag *flag = self.flags[row];
     flagView.flag = flag;

     return flagView;
 }
 - (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
 {
     return ;
 }

 - (void)didReceiveMemoryWarning {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }

 @end

 //
 //  XMGFlag.h
 //  03-国旗选择
 //
 //  Created by xiaomage on 15/6/9.
 //  Copyright (c) 2015年 xiaomage. All rights reserved.
 //

 #import <Foundation/Foundation.h>

 #import <UIKit/UIKit.h>

 @interface XMGFlag : NSObject

 @property (nonatomic, strong) NSString *name;

 @property (nonatomic, strong) UIImage *icon;

 // 写程序一定要有扩展性

 // instancetype: 自动识别当前是哪个类在调用，就会变成对应类的对象

 // 为什么不用id,id 不能使用点语法
 // id 可以调用任何对象的方法，坏处：不利于编译器=检查错误
 + (instancetype)flageWithDict:(NSDictionary *)dict;

 @end

 //
 //  XMGFlag.m
 //  03-国旗选择
 //
 //  Created by xiaomage on 15/6/9.
 //  Copyright (c) 2015年 xiaomage. All rights reserved.
 //

 #import "XMGFlag.h"

 #import <objc/message.h>

 @implementation XMGFlag

 + (instancetype)flageWithDict:(NSDictionary *)dict
 {
     XMGFlag *flag = [[self alloc] init];

     // 利用KVC字典转模型
     [flag setValuesForKeysWithDictionary:dict];

 //    [dict enumerateKeysAndObjectsUsingBlock:^(NSString *key, id obj, BOOL *stop) {
 //
 //
 //        NSString *funcName = [NSString stringWithFormat:@"set%@",key.capitalizedString];
 //
 //        if ([flag respondsToSelector:@selector(funcName)]) {
 //
 //            [flag setValue:obj forKeyPath:key];
 //
 //        }
 //    }];

     return flag;
 }

 - (void)setIcon:(NSString *)icon
 {
 //    NSLog(@"%s",__func__);
     _icon = [UIImage imageNamed:icon];
 }

 // 遍历字典里面所有的key

 //  key：name
 //  就去模型中查找有没有setName:,直接调用这个对象setName:赋值
 //  假如没有找到setName:。就会去模型中查找有没有_name属性，_name = value
 //  假如没有找到_name,还会去模型中查找name属性
 //  最终没有找到，就会直接报错。

 @end

模型

 //
 //  XMGFlagView.h
 //  03-国旗选择
 //
 //  Created by xiaomage on 15/6/9.
 //  Copyright (c) 2015年 xiaomage. All rights reserved.
 //

 #import <UIKit/UIKit.h>
 @class XMGFlag;
 @interface XMGFlagView : UIView

 @property (nonatomic, strong) XMGFlag *flag;

 @end

 //
 //  XMGFlagView.m
 //  03-国旗选择
 //
 //  Created by xiaomage on 15/6/9.
 //  Copyright (c) 2015年 xiaomage. All rights reserved.
 //
 #import "XMGFlag.h"
 #import "XMGFlagView.h"

 @interface XMGFlagView ()
 @property (weak, nonatomic) IBOutlet UIImageView *imageView;
 @property (weak, nonatomic) IBOutlet UILabel *label;

 @end

 @implementation XMGFlagView

 - (void)setFlag:(XMGFlag *)flag
 {
     _flag = flag;

     // 给子控件赋值
     _label.text = flag.name;
     _imageView.image = flag.icon;
 }
 /*
 // Only override drawRect: if you perform custom drawing.
 // An empty implementation adversely affects performance during animation.
 - (void)drawRect:(CGRect)rect {
     // Drawing code
 }
 */

 @end

view

 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="8191" systemVersion="15A284" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES">
     <dependencies>
         <deployment identifier="iOS"/>
         <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="8154"/>
     </dependencies>
     <objects>
         <placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner"/>
         <placeholder placeholderIdentifier="IBFirstResponder" id="-2" customClass="UIResponder"/>
         <view contentMode="scaleToFill" id="YWJ-6W-ap9" customClass="XMGFlagView">
             <rect key="frame" x="0.0" y="0.0" width="375" height="60"/>
             <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
             <subviews>
                 <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" fixedFrame="YES" text="Label" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="bla-Fq-tBg">
                     <rect key="frame" x="0.0" y="0.0" width="90" height="60"/>
                     <animations/>
                     <fontDescription key="fontDescription" type="system" pointSize="17"/>
                     <color key="textColor" red="0.0" green="0.0" blue="0.0" alpha="1" colorSpace="calibratedRGB"/>
                     <nil key="highlightedColor"/>
                 </label>
                 <imageView userInteractionEnabled="NO" contentMode="scaleToFill" horizontalHuggingPriority="251" verticalHuggingPriority="251" fixedFrame="YES" translatesAutoresizingMaskIntoConstraints="NO" id="LkB-3T-KX7">
                     <rect key="frame" x="278" y="0.0" width="102" height="65"/>
                     <animations/>
                 </imageView>
             </subviews>
             <animations/>
             <color key="backgroundColor" white="1" alpha="1" colorSpace="calibratedWhite"/>
             <nil key="simulatedStatusBarMetrics"/>
             <freeformSimulatedSizeMetrics key="simulatedDestinationMetrics"/>
             <connections>
                 <outlet property="imageView" destination="LkB-3T-KX7" id="NPy-qW-igD"/>
                 <outlet property="label" destination="bla-Fq-tBg" id="FNP-89-PLs"/>
             </connections>
             <point key="canvasLocation" x="298.5" y="287"/>
         </view>
     </objects>
 </document>

xib

生日键盘

 //
 //  ViewController.m
 //  04-键盘处理
 //
 //  Created by xiaomage on 15/6/9.
 //  Copyright (c) 2015年 xiaomage. All rights reserved.
 //

 #import "ViewController.h"

 @interface ViewController ()<UITextFieldDelegate>
 @property (weak, nonatomic) IBOutlet UITextField *birthdayField;

 @property (nonatomic, weak) UIDatePicker *datePicker;

 @end

 @implementation ViewController

 #pragma mark - UITextFieldDelegate
 // 是否允许开始编辑
 //- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
 //{
 //    return NO;
 //}

 // 是否允许结束编辑
 //- (BOOL)textFieldShouldEndEditing:(UITextField *)textField
 //{
 //    return NO;
 //}

 // 是否允许用户输入文字
 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
     return NO;
 }

 // 文本框开始编辑的时候调用
 - (void)textFieldDidBeginEditing:(UITextField *)textField
 {
     // 给生日文本框赋值
     [self dateChange:_datePicker];
 }
 - (void)viewDidLoad {
     [super viewDidLoad];
     // Do any additional setup after loading the view, typically from a nib.
     _birthdayField.delegate = self;

     // 自定义生日键盘
     [self setUpBirthdayKeyboard];
 }

 // 自定义生日键盘
 - (void)setUpBirthdayKeyboard
 {
     // 创建UIDatePicker
     // 注意：UIDatePicker有默认的尺寸，可以不用设置frame
     UIDatePicker *picker = [[UIDatePicker alloc] init];

     _datePicker = picker;

     // 设置地区 zh:中国
     picker.locale = [NSLocale localeWithLocaleIdentifier:@"zh"];

     // 设置日期的模式
     picker.datePickerMode = UIDatePickerModeDate;

     // 监听UIDatePicker的滚动
     [picker addTarget:self action:@selector(dateChange:) forControlEvents:UIControlEventValueChanged];

     _birthdayField.inputView = picker;
 }

 // 当UIDatePicker滚动的时候调用
 // 给生日文本框赋值
 - (void)dateChange:(UIDatePicker *)datePicker
 {
     NSLog(@"%@",datePicker.date);
     // 日期转换字符串

     NSDateFormatter *fmt = [[NSDateFormatter alloc] init];

     fmt.dateFormat = @"yyyy-MM-dd";

     NSString *dateStr = [fmt stringFromDate:datePicker.date];

     _birthdayField.text = dateStr;
 }

 - (void)didReceiveMemoryWarning {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }

 @end