UIPickerView 地区解析 -- 全国省、市、区 plist 解析 -- 读取UIPickerView 当前显示内容

一个简单的plist 解析过程，借助UIPickerView 实现了手选全国的 省市区 方法，

源码中有详细注释；长句自己可以拆开看，最好的方法是，拆开，并打印，查看每一步打印的结果，结合Plist文件，解读文件读取过程

基本原理是通过字典 、数组、逐层剥壳

源码：

.h

 //
 //  ViewController.h
 //  AreaAnalysis
 //
 //  Created by Ibokan on 15/8/28.
 //  Copyright (c) 2015年 Crazy凡. All rights reserved.
 //

 #import <UIKit/UIKit.h>

 @interface ViewController : UIViewController <UIPickerViewDelegate, UIPickerViewDataSource>//遵守协议

 @end

.m

 //
 //  ViewController.m
 //  AreaAnalysis
 //
 //  Created by Ibokan on 15/8/28.
 //  Copyright (c) 2015年 Crazy凡. All rights reserved.
 //

 #import "ViewController.h"

 @interface ViewController ()
 @property (weak, nonatomic) IBOutlet UIPickerView *pickerView;
 @property (weak, nonatomic) IBOutlet UILabel *infoLabel;
 @property (nonatomic,strong) NSArray *province;
 @property (nonatomic,strong) NSMutableArray *tempdata;//装载当前省的全部数据
 @property (nonatomic, strong) NSMutableArray  *pickerProvincesData;//当所有省的名称数据
 @property (nonatomic, strong) NSMutableArray  *pickerCitiesData;//当前的省下面的市名称数据
 @property (nonatomic, strong) NSMutableArray  *pickerDistrictData;//当前的市下面的区的名称数据
 @property int ia,ib;
 @end
 @implementation ViewController

 - (void)viewDidLoad {
     [super viewDidLoad];
     // Do any additional setup after loading the view.
     self.province = [[NSArray alloc]initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"area2.plist" ofType:nil]];
     self.pickerProvincesData = [[NSMutableArray alloc]init];
     self.pickerCitiesData = [[NSMutableArray alloc]init];
     self.pickerDistrictData = [[NSMutableArray alloc]init];
     self.tempdata = [[NSMutableArray alloc]init];
     for(int i =  ; i < self.province.count ; [self.pickerProvincesData addObjectsFromArray:[self.province[i++] allKeys]]);//取出所有的keys（省）仅有名称，数据部分是根据省动态获取的
     self.ia = self.ib = ;
     [self getPickerCitiesData];//获取初始化市
     [self getPickerDistrictData];//获取初始化区
     self.pickerView.dataSource = self;
     self.pickerView.delegate = self;
     [self.infoLabel setText:[NSString stringWithFormat:@"%@;%@;%@",self.pickerProvincesData[[self.pickerView selectedRowInComponent:]],self.pickerCitiesData[[self.pickerView selectedRowInComponent:]],self.pickerDistrictData[[self.pickerView selectedRowInComponent:]]]];//让label 显示选中的内容（初始化后显示）
 }
 - (void)getPickerCitiesData//装载市
 {
     [self.pickerCitiesData removeAllObjects];//清除数据
     [self.tempdata removeAllObjects];//清除数据
     [self.tempdata addObjectsFromArray:[[NSArray alloc]initWithArray:[self.province[self.ia] valueForKey:self.pickerProvincesData[self.ia]]]];//将当前省的所有数据保存在一个数组中，避免反复读取
     for(NSDictionary *dir in self.tempdata) { [self.pickerCitiesData addObjectsFromArray:[dir allKeys]]; }//将市的名称取出
 }
 - (void)getPickerDistrictData//装载区
 {
     [self.pickerDistrictData removeAllObjects];
     [self.pickerDistrictData addObjectsFromArray:[self.tempdata [self.ib]valueForKey:self.pickerCitiesData[self.ib]]];//填充区的名称
 }
 #pragma mark 实现协议UIPickerViewDataSource方法
 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {return ; }//设定有几列
 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
     switch (component) {//设定每一列有多少行
         case : return self.pickerProvincesData.count; break;
         case : return self.pickerCitiesData.count; break;
         case : return self.pickerDistrictData.count; break;
         default: break;
     }
     return ;
 }
 #pragma mark 实现协议UIPickerViewDelegate方法
 -(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {//设定行内容
     switch (component) {
         case : return [self.pickerProvincesData objectAtIndex:row]; break;
         case : return [self.pickerCitiesData objectAtIndex:row]; break;
         case : return [self.pickerDistrictData objectAtIndex:row]; break;
         default: break;
     }
     return ;
 }//设定行内容结束
 - (void)pickerView:(UIPickerView *)pickerView  didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
     switch (component) {//检测滑动事件（row 是行  component 是代表滚动的列）
         case :
             self.ia = (int) row;
             self.ib = ;
             [self getPickerCitiesData];//重新装载城市数据
             [self getPickerDistrictData];//重新装载区数据
             [self.pickerView reloadComponent:];//重新填充城市列表
             [self.pickerView reloadComponent:];//重新填充城市列表
             break;
         case :
             self.ib = (int) row;
             [self getPickerDistrictData];
             [self.pickerView reloadComponent:];
             break;
         default: break;
     }
     [self.infoLabel setText:[NSString stringWithFormat:@"%@;%@;%@",self.pickerProvincesData[[self.pickerView selectedRowInComponent:]],self.pickerCitiesData[[self.pickerView selectedRowInComponent:]],self.pickerDistrictData[[self.pickerView selectedRowInComponent:]]]];//刷新 label 显示的内容 （每次滚动后刷新）
 }
 - (void)didReceiveMemoryWarning {
     [super didReceiveMemoryWarning];
     // Dispose of any resources that can be recreated.
 }
 @end

知识点：

先说一下 UIPickerView吧，我只是让你会用，理解的话，自己看文档 command + 鼠标左键   别告诉我不认识英文，我也不认识！

废话不多说：

首先是遵守协议：

<UIPickerViewDelegate, UIPickerViewDataSource>//遵守协议

其次 是实现方法；也就是下面很长这一块；代码中有注释，我再摘出来单独说一下

#pragma mark 实现协议UIPickerViewDataSource方法

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {return 3; }//设定有几列（return  N  就有N列）

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {

switch (component) {//设定每一列有多少行  看参数  component 代表当前在为第几列设定行数，return  N  就会为第几列设定多少行

case 0: return self.pickerProvincesData.count; break;

case 1: return self.pickerCitiesData.count; break;

case 2: return self.pickerDistrictData.count; break;

default: break;

}

return 0;

}

#pragma mark 实现协议UIPickerViewDelegate方法

-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {//设定行内容

switch (component) {//设定行的内容，Component 是列  row 是列中的行，  也就是  给 第几行几列设定值（返回值就是 设定的值）

case 0: return [self.pickerProvincesData objectAtIndex:row]; break;

case 1: return [self.pickerCitiesData objectAtIndex:row]; break;

case 2: return [self.pickerDistrictData objectAtIndex:row]; break;

default: break;

}

return 0;//这里是写代码的失误吧，换成nil 更好 为了保证和上面贴的源码一致，就不改了，下面下载的文件中改过来，大家见谅，

}

- (void)pickerView:(UIPickerView *)pickerView  didSelectRow:(NSInteger)row inComponent:(NSInteger)component {

switch (component) {//检测滑动事件（row 是行  component 是代表滚动的列）  判断滑动的是第几列 然后  刷新数据

case 0:

self.ia = (int) row;

self.ib = 0;

[self getPickerCitiesData];//重新装载城市数据

[self getPickerDistrictData];//重新装载区数据

[self.pickerView reloadComponent:1];//重新填充城市列表

[self.pickerView reloadComponent:2];//重新填充城市列表

break;

case 1:

self.ib = (int) row;

[self getPickerDistrictData];

[self.pickerView reloadComponent:2];

break;

default: break;

}

[self.infoLabel setText:[NSString stringWithFormat:@"%@;%@;%@",self.pickerProvincesData[[self.pickerView selectedRowInComponent:0]],self.pickerCitiesData[[self.pickerView selectedRowInComponent:1]],self.pickerDistrictData[[self.pickerView selectedRowInComponent:2]]]];//刷新 label 显示的内容 （每次滚动后刷新）这句下面有解析，我就不重复了

}

1、

self.province = [[NSArray alloc]initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"area2.plist" ofType:nil]];

不多解释，Plist文件读取，很多次了，

2、

self.pickerProvincesData = [[NSMutableArray alloc]init];

可变数组初始化，记得使用之前一定要初始化，一定要初始化，一定要初始化，重要的事情说三遍！！很小的问题，但是（自己）会经常忘掉，然后找半天错……都是空、都是泪、

3、

for(int i = 0 ; i < self.province.count ; [self.pickerProvincesData addObjectsFromArray:[self.province[i++] allKeys]]);

字典数组怎么取出所有字典的key值，addObjectsFromArray 和 allKeys 的完美搭配

4、

[self.pickerCitiesData removeAllObjects];//清除数据

重新使用可变数组记得清空！！！

5、

[self.infoLabel setText:[NSString stringWithFormat:@"%@;%@;%@",self.pickerProvincesData[[self.pickerView selectedRowInComponent:0]],self.pickerCitiesData[[self.pickerView selectedRowInComponent:1]],self.pickerDistrictData[[self.pickerView selectedRowInComponent:2]]]];

好吧，这句话好长，但是很简单

可以拆为stringWithFormat 和  self.pickerView selectedRowInComponent:0  前一句  应该都懂了，后面一句是取出当前选中的是第几行

下载源码？点我啊