CYC-UIPickerView（省份+城市）

@interface IkrboyViewController : UIViewController{
NSDictionary *dict;//用于存储省份-城市的数据
NSArray *provinceArray;//省份的数组
NSArray *cityArray;//城市的数组，在接下来的代码中会有根据省份的选择进行数据更新的操作
}

在.m的viewDidLoad方法中加上初始化数据的处理。具体处理在initPicker方法

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

//初始化PickerView使用的数据源
-(void)initPicker{
NSBundle *bundle = [NSBundle mainBundle];
NSString *plistPath = [bundle pathForResource:@"provinces_cities" ofType:@"plist"];
dict = [[NSDictionary alloc] initWithContentsOfFile:plistPath];
provinceArray = [dict allKeys];

NSInteger selectedProvinceIndex = [self.pickerView selectedRowInComponent:0];
NSString *seletedProvince = [provinceArray objectAtIndex:selectedProvinceIndex];
cityArray = [dict objectForKey:seletedProvince];
NSLog(@"%d",[provinceArray count]);
}

将数据绑定到UIPickerView

//以下3个方法实现PickerView的数据初始化
//确定picker的轮子个数
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
return 2;
}
//确定picker的每个轮子的item数
- (NSInteger)pickerView:(UIPickerView *)pickerView
numberOfRowsInComponent:(NSInteger)component {
if (component == 0) {//省份个数
return [provinceArray count];
} else {//市的个数
return [cityArray count];
}
}
//确定每个轮子的每一项显示什么内容
#pragma mark 实现协议UIPickerViewDelegate方法
-(NSString *)pickerView:(UIPickerView *)pickerView
titleForRow:(NSInteger)row forComponent:(NSInteger)component {
if (component == 0) {//选择省份名
return [provinceArray objectAtIndex:row];
} else {//选择市名
return [cityArray objectAtIndex:row];
}
}

随时监听UIPickerView的滚动。

//监听轮子的移动
- (void)pickerView:(UIPickerView *)pickerView
didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
if (component == 0) {
NSString *seletedProvince = [provinceArray objectAtIndex:row];
cityArray = [dict objectForKey:seletedProvince];

//重点！更新第二个轮子的数据
[self.pickerView reloadComponent:1];

NSInteger selectedCityIndex = [self.pickerView selectedRowInComponent:1];
NSString *seletedCity = [cityArray objectAtIndex:selectedCityIndex];

NSString *msg = [NSString stringWithFormat:@"province=%@,city=%@", seletedProvince,seletedCity];
NSLog(@"%@",msg);
}
else {
NSInteger selectedProvinceIndex = [self.pickerView selectedRowInComponent:0];
NSString *seletedProvince = [provinceArray objectAtIndex:selectedProvinceIndex];

NSString *seletedCity = [cityArray objectAtIndex:row];
NSString *msg = [NSString stringWithFormat:@"province=%@,city=%@", seletedProvince,seletedCity];
NSLog(@"%@",msg);
}
}

利用下面的代码，获得UIPickerView的不同Component（滚轮）的选中的index

NSInteger selectedProvinceIndex = [self.pickerView selectedRowInComponent:0];
NSInteger selectedCityIndex = [self.pickerView selectedRowInComponent:1];