<?xml version="1.0" encoding="utf-8"?>
<Users>
    <User id="1">
        <name>Tom</name>
        <age>20</age>
    </User>
    <User id="2">
        <name id = "222">John</name>
        <age>33</age>
    </User>
    <User>
        <name id = "333">Eric</name>
        <age>43</age>
    </User>
    <User>
        <name id = "444">Tony</name>
        <age>54</age>
    </User>
</Users>

//
//  Person.h
//  XmlDemo
//
//  Created by City--Online on 15/4/29.
//  Copyright (c) 2015年 CYW. All rights reserved.
//

#import <Foundation/Foundation.h>

@interface Person : NSObject

@property(nonatomic,strong)NSString *Pid;

@property(nonatomic,strong)NSString *Name;

@property(nonatomic,assign)int Age;
@end

//
//  ViewController.m
//  XmlDemo
//
//  Created by City--Online on 15/4/29.
//  Copyright (c) 2015年 CYW. All rights reserved.
//

#import "ViewController.h"
#import "Person.h"

@interface ViewController () <NSXMLParserDelegate>
@property (nonatomic, strong) NSMutableArray *personArray;
@property (nonatomic, strong) NSMutableString *element;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

//    XML的解析方式有2种
//    DOM:一次性将整个XML文档加载进内存,比较适合解析小文件 文档驱动
//    SAX:从根元素开始,按顺序一个元素一个元素往下解析,比较适合解析大文件 事件驱动

    //IOS自带的属于SAX事件驱动的解析方式
//    就是一个事物模型解析，从头开始读取文档然后根据读取到的头标签,读完头标签后，理论上是读取标签值,然后读取后遇到结束标签等
    NSString *path=[[NSBundle mainBundle]pathForResource:@"user" ofType:@"xml"];
    NSURL *url=[[NSURL alloc]initFileURLWithPath:path];
    //实例化
    NSXMLParser *parser=[[NSXMLParser alloc]initWithContentsOfURL:url];
    //设置代理
    parser.delegate=self;
    //开始解析
    [parser parse];

}
// step1 开始解析
-(void)parserDidStartDocument:(NSXMLParser *)parser
{
    self.personArray = [[NSMutableArray alloc] initWithCapacity:0];
    self.element = [[NSMutableString alloc] init];
}

//step2 开始解析元素 获取头标签的信息<>里面的属性、名字
-(void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"Users"]) {
        NSLog(@"进入<Users>");
    }
    if ([elementName isEqualToString:@"User"]) {
         NSLog(@"进入<User>");
        Person *user = [[Person alloc] init];
        [_personArray addObject:user];
    }
    if ([elementName isEqualToString:@"name"]) {
        NSLog(@"进入<name>");
        Person *user = [_personArray objectAtIndex:[_personArray count] -1];
        user.Pid = [attributeDict objectForKey:@"id"];
    }
    if ([elementName isEqualToString:@"age"]) {
        NSLog(@"进入<age>");
    }

}
//step3 获得首尾标签间 > < 的内容
//此处分几种情况:
//1.当标签间内容为“”,如果</></>(如图</age></User></Users>)则进入step4,否则进入step2
//2.当标签间内容不为“”,则进入step4
- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string
{
    NSLog(@"%@", string);

    //获取文本节点中的数据，因为下面的方法要保存这里获取的数据，所以要定义一个全局变量(可修改的字符串)
    //这里要赋值为空，目的是为了清空上一次的赋值
    [_element setString:@""];
    [_element appendString:string];//string是获取到的文本节点的值，只要是文本节点都会获取(包括换行)，然后到下个方法中进行判断区分
}
//step4 标签解析结束</>
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName
  namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName {
//    NSLog(@"%@", elementName);
    NSString *str=[[NSString alloc] initWithString:_element];

    if ([elementName isEqualToString:@"Users"]) {
        NSLog(@"</Users>= %@",str);
    }
    if ([elementName isEqualToString:@"name"]) {
        NSLog(@"</name>=%@",str);
        Person *user = [_personArray objectAtIndex:[_personArray count] -1];
        user.Name = str;
    }
    if ([elementName isEqualToString:@"age"]) {
        NSLog(@"</age>=%@",str);
        Person *user = [_personArray objectAtIndex:[_personArray count] -1];
        user.age = (int)[str integerValue];
    }
    if ([elementName isEqualToString:@"User"]) {
        NSLog(@"</User>=%@ ",str);
    }
}
//step5 解析结束
-(void)parserDidEndDocument:(NSXMLParser *)parser
{
    for (Person *p in self.personArray) {
        NSLog(@"%@  %d %@",p.Name,p.Age,p.Pid);
    }
}
//解析报错
-(void)parser:(NSXMLParser *)parser parseErrorOccurred:(NSError *)parseError
{
    NSLog(@"解析有误 Error:%@",parseError);

}

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

@end