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
1 // 2 // ViewController.h 3 // AreaAnalysis 4 // 5 // Created by Ibokan on 15/8/28. 6 // Copyright (c) 2015年 Crazy凡. All rights reserved. 7 // 8 9 #import <UIKit/UIKit.h> 10 11 @interface ViewController : UIViewController <UIPickerViewDelegate, UIPickerViewDataSource>//遵守协议 12 13 14 @end
.m
1 //
2 // ViewController.m
3 // AreaAnalysis
4 //
5 // Created by Ibokan on 15/8/28.
6 // Copyright (c) 2015年 Crazy凡. All rights reserved.
7 //
8
9 #import "ViewController.h"
10
11 @interface ViewController ()
12 @property (weak, nonatomic) IBOutlet UIPickerView *pickerView;
13 @property (weak, nonatomic) IBOutlet UILabel *infoLabel;
14 @property (nonatomic,strong) NSArray *province;
15 @property (nonatomic,strong) NSMutableArray *tempdata;//装载当前省的全部数据
16 @property (nonatomic, strong) NSMutableArray *pickerProvincesData;//当所有省的名称数据
17 @property (nonatomic, strong) NSMutableArray *pickerCitiesData;//当前的省下面的市名称数据
18 @property (nonatomic, strong) NSMutableArray *pickerDistrictData;//当前的市下面的区的名称数据
19 @property int ia,ib;
20 @end
21 @implementation ViewController
22
23 - (void)viewDidLoad {
24 [super viewDidLoad];
25 // Do any additional setup after loading the view.
26 self.province = [[NSArray alloc]initWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"area2.plist" ofType:nil]];
27 self.pickerProvincesData = [[NSMutableArray alloc]init];
28 self.pickerCitiesData = [[NSMutableArray alloc]init];
29 self.pickerDistrictData = [[NSMutableArray alloc]init];
30 self.tempdata = [[NSMutableArray alloc]init];
31 for(int i = 0 ; 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
32 self.ia = self.ib = 0;
33 [self getPickerCitiesData];//获取初始化市
34 [self getPickerDistrictData];//获取初始化区
35 self.pickerView.dataSource = self;
36 self.pickerView.delegate = self;
37 [self.infoLabel setText:[NSString stringWithFormat:@"%@;%@;%@",self.pickerProvincesData[[self.pickerView selectedRowInComponent:0]],self.pickerCitiesData[[self.pickerView selectedRowInComponent:1]],self.pickerDistrictData[[self.pickerView selectedRowInComponent:2]]]];//让label 显示选中的内容（初始化后显示）
38 }
39 - (void)getPickerCitiesData//装载市
40 {
41 [self.pickerCitiesData removeAllObjects];//清除数据
42 [self.tempdata removeAllObjects];//清除数据
43 [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
44 for(NSDictionary *dir in self.tempdata) { [self.pickerCitiesData addObjectsFromArray:[dir allKeys]]; }//将市的名称取出
45 }
46 - (void)getPickerDistrictData//装载区
47 {
48 [self.pickerDistrictData removeAllObjects];
49 [self.pickerDistrictData addObjectsFromArray:[self.tempdata [self.ib]valueForKey:self.pickerCitiesData[self.ib]]];//填充区的名称
50 }
51 #pragma mark 实现协议UIPickerViewDataSource方法
52 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {return 3; }//设定有几列
53 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
54 switch (component) {//设定每一列有多少行
55 case 0: return self.pickerProvincesData.count; break;
56 case 1: return self.pickerCitiesData.count; break;
57 case 2: return self.pickerDistrictData.count; break;
58 default: break;
59 }
60 return 0;
61 }
62 #pragma mark 实现协议UIPickerViewDelegate方法
63 -(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {//设定行内容
64 switch (component) {
65 case 0: return [self.pickerProvincesData objectAtIndex:row]; break;
66 case 1: return [self.pickerCitiesData objectAtIndex:row]; break;
67 case 2: return [self.pickerDistrictData objectAtIndex:row]; break;
68 default: break;
69 }
70 return 0;
71 }//设定行内容结束
72 - (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
73 switch (component) {//检测滑动事件（row 是行 component 是代表滚动的列）
74 case 0:
75 self.ia = (int) row;
76 self.ib = 0;
77 [self getPickerCitiesData];//重新装载城市数据
78 [self getPickerDistrictData];//重新装载区数据
79 [self.pickerView reloadComponent:1];//重新填充城市列表
80 [self.pickerView reloadComponent:2];//重新填充城市列表
81 break;
82 case 1:
83 self.ib = (int) row;
84 [self getPickerDistrictData];
85 [self.pickerView reloadComponent:2];
86 break;
87 default: break;
88 }
89 [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）
90 }
91 - (void)didReceiveMemoryWarning {
92 [super didReceiveMemoryWarning];
93 // Dispose of any resources that can be recreated.
94 }
95 @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