IOS之简略选择器UIPickerView（省份+城市）

IOS之简单选择器UIPickerView（省份+城市）

? ? ? ? 先介绍一下我们要实现什么功能。有1个选择器，有左右两个轮子，做轮子选择省份，右轮子选择城市，其中选择省份时，右边的城市会自动更新。

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1、首先，对UIPickerView绑定Delegate和DataSource。此处不再赘述。

2、首先实现数据的初始化。

（1）在.h文件中定义如下变量。其中provinces_cities.plist请见附件。

@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}

?（2）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
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- (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]);}

?3、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 *)pickerViewnumberOfRowsInComponent:(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 *)pickerViewtitleForRow:(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];}}

?4.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);    }}

?附加说明：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];

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