一、点菜系统练习（UIPickerView）
<1>UIPickerView的常用代理方法介绍
#pragma mark - <UIPickerViewDelegate> // 返回指定列的行宽度
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component
{ }
// 返回指定列中行的高度
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
{ } // 返回第component列的第row行的字符串
- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{ }
// 富文本属性，可以描述文字的大小和颜色
- (nullable NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component
{ }
// 返回一个UIView 第component列第row行
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(nullable UIView *)view
{ }
// 人为选择第component列第row行之后执行的代码
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{ }
<2>UIPickerView必须实现的两个数据源方法
#pragma mark - <UIPickerViewDataSource> // 告诉pickView有多少列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return self.foods.count;
} // 告诉pickView的component列中有多少行
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return [self.foods[component] count];
}
<3>练习代码
#import "ViewController.h" @interface ViewController () <UIPickerViewDataSource,UIPickerViewDelegate>
@property (weak, nonatomic) IBOutlet UIPickerView *pickView;
/** 数据集合 */
@property(nonatomic,strong) NSArray *foods;
@property (weak, nonatomic) IBOutlet UILabel *fruitLabel;
@property (weak, nonatomic) IBOutlet UILabel *mainLabel;
@property (weak, nonatomic) IBOutlet UILabel *drinkLabel; @end @implementation ViewController - (void)viewDidLoad {
[super viewDidLoad];
for (int i = ; i < self.foods.count; i++) {
[self pickerView:self.pickView didSelectRow: inComponent:i];
} }
// 随机
- (IBAction)random:(id)sender {
for (int i = ; i <self.foods.count; i++) {
int r = arc4random_uniform((int)[self.foods[i] count]);
[self.pickView selectRow:r inComponent:i animated:YES];
[self pickerView:self.pickView didSelectRow:r inComponent:i];
}
} // 懒加载数据
- (NSArray *)foods
{
if (_foods == nil) {
NSString *path = [[NSBundle mainBundle] pathForResource:@"foods.plist" ofType:nil];
_foods = [NSArray arrayWithContentsOfFile:path];
}
return _foods;
} #pragma mark - <UIPickerViewDataSource> // 告诉pickView有多少列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return self.foods.count;
} // 告诉pickView的component列中有多少行
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return [self.foods[component] count];
} #pragma mark - <UIPickerViewDelegate> // 返回指定列中行的高度
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
{
return ;
} // 返回第component列的第row行的字符串
- (nullable NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
return self.foods[component][row];
} // 人为选择第component列第row行之后执行的代码
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
switch (component) {
case :
self.fruitLabel.text = self.foods[component][row];
break;
case :
self.mainLabel.text = self.foods[component][row];
break;
case :
self.drinkLabel.text = self.foods[component][row];
break;
}
} @end
二、国旗选择练习（pickerView每行都是返回一个自定义控件）
//
// ViewController.m
// 0322国旗选择
//
// Created by admin on 16/3/22.
// Copyright © 2016年 admin. All rights reserved.
// #import "ViewController.h"
#import "ChaosFlag.h"
#import "ChaosFlagView.h" @interface ViewController () <UIPickerViewDataSource,UIPickerViewDelegate>
/** 数据模型集合 */
@property(nonatomic,strong) NSMutableArray *flags;
@property (weak, nonatomic) IBOutlet UIPickerView *pickView; @end @implementation ViewController - (void)viewDidLoad {
[super viewDidLoad];
_pickView.delegate = self;
_pickView.dataSource = self;
}
- (NSMutableArray *)flags
{
if (_flags == nil) {
NSString *path = [[NSBundle mainBundle] pathForResource:@"flags.plist" ofType:nil];
NSArray *dicArray = [NSArray arrayWithContentsOfFile:path];
NSMutableArray *arr = [NSMutableArray array];
for (NSDictionary *dict in dicArray) {
ChaosFlag *flag = [ChaosFlag flagWithDict:dict];
[arr addObject:flag];
}
_flags = arr;
}
return _flags;
} #pragma mark - <UIPickerViewDataSource>
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
return self.flags.count;
} - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return ;
} #pragma mark - 代理方法
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
// 加载xib
ChaosFlagView *flagView = [[NSBundle mainBundle] loadNibNamed:@"ChaosFlagView" owner:nil options:nil][];
ChaosFlag *flag = self.flags[row];
flagView.flag = flag;
return flagView;
}
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component
{
return ;
}
@end
三、生日选择，省市二级联动
//
// ViewController.m
// 0323-生日城市选择器
//
// Created by admin on 16/3/23.
// Copyright © 2016年 admin. All rights reserved.
// #import "ViewController.h"
#import "ChaosProvince.h" @interface ViewController () <UITextFieldDelegate,UIPickerViewDataSource,UIPickerViewDelegate>
@property (weak, nonatomic) IBOutlet UITextField *birthdayLabel;
@property (weak, nonatomic) IBOutlet UITextField *cityLabel; /** 数据集合 */
@property(nonatomic,strong) NSMutableArray *provinces; /** datePicker */
@property(nonatomic,strong) UIDatePicker *datePicker;
/** pickView */
@property(nonatomic,strong) UIPickerView *pickView;
/** 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 */
@property(nonatomic,assign) NSInteger proIndex;
@end @implementation ViewController // 重写get方法，实现懒加载
- (NSMutableArray *)provinces
{
if (_provinces == nil) {
// 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！
_provinces = [NSMutableArray array];
NSString *path = [[NSBundle mainBundle] pathForResource:@"provinces.plist" ofType:nil];
NSArray *dicArray = [NSArray arrayWithContentsOfFile:path];
for (NSDictionary *dict in dicArray) {
ChaosProvince *province = [ChaosProvince provinceWithDict:dict];
[_provinces addObject:province];
}
}
return _provinces;
} - (void)viewDidLoad {
[super viewDidLoad]; _cityLabel.delegate = self; _birthdayLabel.delegate = self;
[self setBirthdayInputView];
[self setCitiesInputView];
}
/** 给文本框设置时间选择器的方法 */
- (void)setBirthdayInputView
{
// 给生日文本框设置datePicker
_datePicker = [[UIDatePicker alloc] init];
// 设置时间选择器的语言 zh--中国
_datePicker.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"zh"];
// 设置时间选择器显示的时间格式
_datePicker.datePickerMode = UIDatePickerModeDate;
_birthdayLabel.inputView = _datePicker;
// 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）
[_datePicker addTarget:self action:@selector(dateChange:) forControlEvents:UIControlEventValueChanged];
}
/** 监听时间选择器改变的方法 */
- (void)dateChange:(UIDatePicker *)datePicker
{
// 取出时间
NSDate *date = datePicker.date;
// NSDate与NSString之间的转换
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
formatter.dateFormat =@"yyyy-MM-dd";
NSString *time = [formatter stringFromDate:date];
_birthdayLabel.text = time;
} /** 给城市文本框设置选择器的方法 */
- (void)setCitiesInputView
{
_pickView = [[UIPickerView alloc] init];
_pickView.delegate = self;
_pickView.dataSource = self;
_cityLabel.inputView = _pickView;
} #pragma mark - pickView数据源方法
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
if (component == ) { // 省的个数
return self.provinces.count;
} else { // 省对应的城市
ChaosProvince *province = self.provinces[self.proIndex];
return province.cities.count;
}
} - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return ; // 两列
} #pragma mark - pickerView代理方法
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
if (component == ) { // 省
ChaosProvince *province = self.provinces[row];
return province.name;
}
else // 城市
{
// 根据省的索引获取对应的城市
ChaosProvince *province = self.provinces[self.proIndex];
return province.cities[row];
}
} // 滚动pickerView就调用
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
if (component == ) { // 选择省,刷新相应的城市
[pickerView reloadComponent:];
// 记录当前选中的省会索引
self.proIndex = [pickerView selectedRowInComponent:];
}
// 显示到文本框中 // 选中的省
ChaosProvince *province = self.provinces[self.proIndex]; // 选中的城市
NSInteger cityIndex = [pickerView selectedRowInComponent:];
self.cityLabel.text = [NSString stringWithFormat:@"%@ %@",province.name,province.cities[cityIndex]]; } #pragma mark - <UITextFieldDelegate>
// 文本框开始编辑的时候执行的方法
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
if (textField == self.birthdayLabel) { //生日文本 [self dateChange:_datePicker];
} else if (textField == self.cityLabel) { // 城市文本
[self pickerView:self.pickView didSelectRow: inComponent:];
}
} // 是否允许在范围内改变字符
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
return NO;
}
@end