省市选择器

效果图：

不多说奉上代码：

//
//  areaPickerView.m
//  省市选择器
//
//  Created by iBokanwisdom on 15/8/31.
//  Copyright (c) 2015年 pangLee. All rights reserved.
//

#import "areaPickerView.h"

@interface areaPickerView ()
//创建一个UIPickerView
@property (nonatomic,strong) UIPickerView *areaPickerView;
//显示当前选定的省市区
@property (nonatomic,strong) UILabel * areaShowLabel;

//存储第一次解析的省市字典
@property (nonatomic,strong) NSDictionary * areaData;
//存储第二次解析的省市字典
@property (nonatomic,strong) NSDictionary * provinceData;

//储存省市数组
@property (nonatomic,strong) NSMutableArray * province;
//存放省下级市
@property (nonatomic,strong) NSMutableArray * city;
//存放市下级区县
@property (nonatomic,strong) NSMutableArray * district;
@end

@implementation areaPickerView

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //初始化显示Label
    self.areaShowLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 270, 320, 50)];
    self.areaShowLabel.backgroundColor = [UIColor groupTableViewBackgroundColor];
    self.areaShowLabel.textAlignment = NSTextAlignmentCenter;
    [self.view addSubview: self.areaShowLabel];
    
    //初始化UIPickerViw
    self.areaPickerView = [[UIPickerView alloc]initWithFrame:CGRectMake(0, 55, 320, 160)];
    [self.view addSubview:self.areaPickerView];
    
    //先解析plist文件 将数据存储到数组中
    [self analysisAreaPlist];
    //默认显示第一列第一行第二列第一行 第三列第一行数据
    [self analysisAreaPlistGetCityInformationWithComponentRow:0];
    [self districtInformationWithComponetRow:0];
    //显示Label
    [self displayLable];
    
    self.areaPickerView.delegate = self;
    self.areaPickerView.dataSource = self;
}

- (void)analysisAreaPlist
{
    //第一次解析plist文件 将数据全部存储到areaData字典中
    self.areaData = [NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"area.plist" ofType:nil]];
    //初始化省市数组
    self.province = [[NSMutableArray alloc]init];
    //根据键值 循环获取 省 信息并存到province数组中
    for(int i = 0;i < self.areaData.count ;i++)
    {
        //从plist文件中可以看出
        //从字典中根据i值获取所有键值,获取每个字典下的第一个数据就是省信息
        [self.province addObject:[[[self.areaData valueForKey:[NSString stringWithFormat:@"%d",i]] allKeys]objectAtIndex:0]];
    }
}

//根据第一列的省市获取 省市的下级市
- (void)analysisAreaPlistGetCityInformationWithComponentRow:(NSInteger)row
{
    //第二次解析第一次的字典 获取省市下级市的信息存到provinceData中
    self.provinceData = [[self.areaData objectForKey:[NSString stringWithFormat:@"%ld",row]] objectForKey:self.province[row]];
    
    //初始化下级市数组
    self.city = [[NSMutableArray alloc]init];
    //循环获取下级市信息 存到city数组中
    for(int i = 0;i < self.provinceData.count;i++)
    {
        [self.city addObject:[[[self.provinceData valueForKey:[NSString stringWithFormat:@"%d",i]] allKeys]objectAtIndex:0]];
    }
}

//获取下级市的下级区县信息
- (void)districtInformationWithComponetRow:(NSInteger)row
{
    //初始化区县数组  ??为什么在此初始化而不是在外面？
    //因为每次滑动改变省市时，省市的下级市，下级区县都是变化的 都是要重新获取的，否则就会造成可变数组数据的继续累积
    self.district = [[NSMutableArray alloc]init];
    self.district = [[self.provinceData objectForKey:[NSString stringWithFormat:@"%ld",row]] objectForKey:self.city[row]];
}

//显示Label
- (void)displayLable
{
    //获取第一列当前行
    NSString *provinceText =[self.province objectAtIndex:[self.areaPickerView selectedRowInComponent:0]];
    //获取第二列当前行
    NSString *cityText =[self.city objectAtIndex:[self.areaPickerView selectedRowInComponent:1]];
    //获取第三列当前行
    NSString *districtText =[self.district objectAtIndex:[self.areaPickerView selectedRowInComponent:2]];
    //在label中显示
    self.areaShowLabel.text = [NSString stringWithFormat:@"%@-%@-%@",provinceText,cityText,districtText];
}


//获取UIPickerView列数
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    //省市 省下级市 区  一共三列 所以返回值为三
    return 3;
}

//获取UIPickerView每列的行数
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    if(component == 0)
    {
        return self.province.count;
    }
    if(component == 1)
    {
        return self.city.count;
    }
    if(component == 2)
    {
         return self.district.count;
    }
    return 0;
}

//设置每列显示什么信息  第一列显示省市 第二列显示下级市 第三列显示下级县区
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    if(component == 0)
    {
       return [self.province objectAtIndex:row];
    }
    if(component == 1)
    {
        return [self.city objectAtIndex:row];
    }
    if(component == 2)
    {
        return [self.district objectAtIndex:row];
    }
    return 0;
}


//监听滚轮 滚动的是第一列还是第二列 联动事件
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    if(component == 0)
    {
        //如果滚动第一列 要根据第一列的行 去获取第二列的信息再根据第二列的行去获取第三列的信息
        //默认是滚动第一列显示第二列首行 第三列首行
        [self analysisAreaPlistGetCityInformationWithComponentRow:row];
        [self districtInformationWithComponetRow:0];
        //刷新UIPickerView
        [self.areaPickerView reloadComponent:1];
        [self.areaPickerView reloadComponent:2];
        
    }
    if(component == 1)
    {
        //滚动第二列 第一列不动 第三列随行数变化
        [self districtInformationWithComponetRow:row];
        [self.areaPickerView reloadComponent:2];
    }
    //显示在Label上
    [self displayLable];
}

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

@end