UIPickerView和UIDatePicker使用起来相对比较简单，下面通过简单例子深入掌握它们。
UIPickerView
属性
// 数据源(用来告诉UIPickerView有多少列多少行)
@property(nonatomic,assign) id<UIPickerViewDataSource> dataSource;
// 代理(用来告诉UIPickerView每1列的每1行显示什么内容,监听UIPickerView的选择)
@property(nonatomic,assign) id<UIPickerViewDelegate> delegate;
// 是否要显示选中的指示器
@property(nonatomic) BOOL showsSelectionIndicator;
// 一共有多少列
@property(nonatomic,readonly) NSInteger numberOfComponents;
方法
// 重新刷新所有列
- (void)reloadAllComponents;
// 重新刷新第component列
- (void)reloadComponent:(NSInteger)component;
// 主动选中第component列的第row行
- (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated;
// 获得第component列的当前选中的行号
- (NSInteger)selectedRowInComponent:(NSInteger)component;
数据源方法
// 一共有多少列
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView;
// 第component列一共有多少行
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component;
代理方法
// 第component列的宽度是多少
- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component;
// 第component列的行高是多少
- (CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component;
// 第component列第row行显示什么文字
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component;
// 第component列第row行显示怎样的view(内容)
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view;
// 选中了pickerView的第component列第row行
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component;
例子（联动效果）
创建UIPickerView,设置代理和数据源，添加到view
UIPickerView *pickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0,64,320, 200)];
pickerView.dataSource = self;
pickerView.delegate = self;
[self.view addSubview:pickerView];
懒加载省市数据
@property (nonatomic,strong) NSArray *provinces;
-(NSArray *)provinces{
if (_provinces == nil) {
NSMutableArray *provincesArr = [NSMutableArray array];
NSArray *arr = [NSArray arrayWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"cities.plist" ofType:nil]];
for (NSDictionary *dict in arr) {
ZXHProvince *province = [ZXHProvince provinceWithDict:dict];
[provincesArr addObject:province];
}
_provinces = provincesArr;
}
return _provinces;
}
实现数据源方法。返回多少列，每一列多少行
#pragma mark 数据源
//返回多少列
-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
NSLog(@"==数据源==numberOfComponentsInPickerView:");
return 2;
}
//返回每一列多少行
-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{
NSLog(@"==数据源===numberOfRowsInComponent");
if (component==0) {//省份
return self.provinces.count;
}else{//市
//获得选中了哪一个省
NSInteger index = [pickerView selectedRowInComponent:0];
ZXHProvince *province = self.provinces[index];
NSArray *cities = province.cities;
return cities.count;
}
}
实现代理方法。注意：监听省份的时候要刷新第二列城市，重新设置城市数据
#pragma mark 代理方法
//显示的数据
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{
NSLog(@"== 代理方法===titleForRow=====%ld",row);
if (component==0) {
ZXHProvince *province = self.provinces[row];
return province.name;
}else{
//获得选中了哪一个省
NSInteger index = [pickerView selectedRowInComponent:0];
ZXHProvince *province = self.provinces[index];
return province.cities[row];
}
}
/**
* 监听选中了某一列的某一行
**/
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{
if (component==0) {//省份
// 刷新第1列的数据(重新刷新数据，重新调用数据源和代理的相应方法获得数据)
[pickerView reloadComponent:1];
//默认显示
[pickerView selectRow:0 inComponent:1 animated:YES];
}
//更改显示文字
//选择省份
ZXHProvince *province;
NSInteger pIndex = [pickerView selectedRowInComponent:0];
province = self.provinces[pIndex];
NSString *name = province.name;
//城市
NSInteger cIndex = [pickerView selectedRowInComponent:1];
NSString *city = province.cities[cIndex];
self.showTextLable.text = [NSString stringWithFormat:@"省份：%@ 城市：%@",name,city];
}
模型数据代码（略）
效果图
自定义view
既可显示文字组也可显示自定义view。当要在行中显示view，则实现一下代理方法，返回自定义view。
#pragma mark 代理方法
/**
* 第component列的第row行显示怎样的view
* 每当有一行内容出现在视野范围内,就会调用(调用频率高) 不用使用标识
*/
-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{
// UIView *v = [[UIView alloc]init];
// v.backgroundColor = [UIColor redColor];
// v.frame =CGRectMake(0, 0,320,100);
//
// UIButton *btn = [[UIButton alloc] initWithFrame:CGRectMake(100, 20, 100,30)];
// [btn setTitle:@"test" forState:UIControlStateNormal];
// [UIButton buttonWithType:UIButtonTypeContactAdd];
// [v addSubview:btn];
// return v;
ZXHFlagView *flagView = [ZXHFlagView flagViewWithreusingView:view];
flagView.flag = self.flags[row];
return flagView;
}
效果图
UIDatePicker
属性
// datePicker的显示模式
@property (nonatomic) UIDatePickerMode datePickerMode;
// 显示的区域语言
@property (nonatomic, retain) NSLocale *locale;
监听UIDatePicker的选择
因为UIDatePicker继承自UIControl,所以通过addTarget:...监听
使用
创建UIDatePicker
UIDatePicker *datePicker = [[UIDatePicker alloc]init];
设置日期格式和语言
/*
UIDatePickerModeTime, // Displays hour, minute, and optionally AM/PM designation depending on the locale setting (e.g. 6 | 53 | PM)
UIDatePickerModeDate, // Displays month, day, and year depending on the locale setting (e.g. November | 15 | 2007)
UIDatePickerModeDateAndTime, // Displays date, hour, minute, and optionally AM/PM designation depending on the locale setting (e.g. Wed Nov 15 | 6 | 53 | PM)
UIDatePickerModeCountDownTimer, // Displays hour and minute (e.g. 1 | 53)
*/
datePicker.datePickerMode = UIDatePickerModeDate;
datePicker.locale = [[NSLocale alloc] initWithLocaleIdentifier:@"zh_CN"];
监听选择的日期时间
[datePicker addTarget:self action:@selector(birthdayChange:) forControlEvents:UIControlEventValueChanged];
添加到view显示
[self.view addSubview:datePicker];
效果图
参考：https://blog.csdn.net/zhixinhuacom/article/details/49643753
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