OC学习小总结

一、下载

下载的几种方式

 

同步下载三种方法

//网页下载
    NSURL *url=[NSURL URLWithString:@"http://www.baidu.com/?tn=96581013_hao_pg"];
    NSString *str = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil] ;
    NSLog(@"000000%@",str);

2.//根据下载方法需要什么，定义什么
    NSURL *url=[NSURL URLWithString:@"http://www.baidu.com/img/bdlogo.png"];
    NSURLRequest *request=[NSURLRequest requestWithURL:url];
//创建指针
    NSURLResponse *response;
    NSError *error;

   NSData *data = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
    //如果下载失败就打印fail
    if (error) {
        NSLog(@"fail");
        return;
    }

//将response强制转化为NSHTTPURLResponse类型，因为statusCode是NSHTTPURLResponse的一个属性
    NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
    //请求成功状态码为200，写入文件
    if (httpResponse.statusCode == 200) {
        [data writeToFile:@"/Users/apple/Desktop/test.png" atomically:YES];
        
    }

3.
    NSURL *url=[NSURL URLWithString:@"http://www.baidu.com/img/bdlogo.png"];
   //读取网络URL里面的内容
    NSData *data=[NSData dataWithContentsOfURL:url];
    //将data内容写入文件
    [data writeToFile:@"/Users/apple/Desktop/test.png" atomically:YES];

异步下载二种方法

2.根据协议封装下载文件

在down.h中

#import <Foundation/Foundation.h>
@class download;
//定义协议及协议方法
@protocol downloaddelegate<NSObject>
@optional
-(void)downloadprocess:(float)process;
@required
-(void)downloadfinished:(download *)down;

@end
//挂出下载协议方法
@interface download : NSObject <NSURLConnectionDataDelegate>
@property(nonatomic,weak)id<downloaddelegate>delege;
@property (nonatomic, copy) NSString *path;
@property (nonatomic, copy)NSMutableData *data1;

-(void)download;
- (void)start;
@end

在down.m中

#import "download.h"
@interface download()
{
    NSURLConnection *connection;
    long long totallegth;
    
}
@end
@implementation download

- (id)initWithPath:(NSString *)path
{
    if (self = [super init]) {
        self.path = path;
    }
    
    return self;
}

-(void)download
{
    NSURL *url=[NSURL URLWithString:_path];
    NSLog(@"路径%@",_path);
    NSURLRequest *request=[NSURLRequest requestWithURL:url];
    connection=[NSURLConnection connectionWithRequest:request delegate:self];
    
    
    
}

- (void)start
{
//    开始下载
    [connection start];
}

//判断是否出错
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{

    NSLog(@"下载出错%@",error);

}

//请求响应
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{


    NSHTTPURLResponse *httprespose=(NSHTTPURLResponse *)response;
    if (httprespose.statusCode==200) {
        totallegth=httprespose.expectedContentLength;
    }
    NSLog(@"预计总长度%lld",totallegth);



}




//接收数据
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
    _data1=[[NSMutableData alloc]init];
    
    [_data1 appendData:data];

    //对于Optional修饰的方法，需要做判断后才能调用

    if (_delege && [_delege respondsToSelector:@selector(downloadprocess:)]){
        NSLog(@"下载选择");
        
        [_delege downloadprocess:(float)_data1.length/totallegth];
    }

}

//下载完成
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    //3. 使用指针调用协议方法

    NSLog(@"调用协议的方法。。。");
    [_delege downloadfinished:self];
}

@end

在ViewController.m中

#import "ViewController.h"
#import "download.h"
@interface ViewController() <downloaddelegate>

@end

@implementation ViewController
            
- (void)viewDidLoad {
    [super viewDidLoad];
    download *downloader = [[download alloc] init];
    downloader.path=@"http://www.baidu.com";
    [downloader download];
    //在两个类中对象间建立联系
    downloader.delege=self;

    download *downloader2=[[download alloc] init];
    downloader2.path=@"https://github.com/nicklockwood/iVersion";
    [downloader2 download];
    downloader2.delege=self;
    
    // Do any additional setup after loading the view, typically from a nib.
}
//协议中必须实现的方法
-(void)downloadfinished:(download *)down
{
    NSString *str = [[NSString alloc] initWithData:down.data1 encoding:NSUTF8StringEncoding];
    NSLog(@"下载完成。。%@",str);
}
//协议中可选实现的方法
-(void)downloadprocess:(float)process
{
    NSLog(@"下载正在进行。。");
    NSLog(@"progress进程: %.2f", process);


}

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

@end

 二、协议

OC协议：实际上就是两个对象直接的通信

一个对象的任务让另一个对象完成，也叫代理模式。

协议的工作流程：

             类A                                                                          类B

 类A不想实现，因此需要外包出去                            

 1）先制定一个协议（方法列表）         　　　　　　　　　　 1）如果类B想接单，需先具备资质（挂出协议）

 2）类A的对象需要能找到类B的对象（delegate指针引用）   　2）类B需要实现require的方法，可选实现optional的方法

 3）类A的对象想完成这些工作时,通过代理让类B的对象干活 

          

列子如下：

先制定协议

@protocol BiteDelegate <NSObject>
//可选实现方法
@optional
- (void)bitepeople:(id)someone;

@end

在Person.h中

#import <Foundation/Foundation.h>
#import "BiteDelgate.h"
#import "Dog.h"
#import "Cat.h"


@interface Person : NSObject
//设置Dog属性
@property(nonatomic,strong) Dog *dog;
@property(nonatomic,strong) Cat *cat;
@property(nonatomic,strong)id<BiteDelegate>delegate;

@end

在Person.m中

#import "Person.h"
#import "Dog.h"
#import "Cat.h"
@implementation Person

@end

在Dog.h中

#import <Foundation/Foundation.h>
#import "BiteDelgate.h"
//挂出协议
@interface Dog : NSObject <BiteDelegate>

@end

在Dog.m中

#import "Dog.h"

@implementation Dog

-(void)bitepeople:(id)someone
{

    NSLog(@"咬死他");
}


@end

在Cat.h中

#import <Foundation/Foundation.h>

@interface Cat : NSObject

@end

在Cat.m中

#import "Cat.h"

@implementation Cat

@end

 三、数据解析

1.Json解析

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // json里面只有5种数据类型NSsting、NSdictiongnary，NSnumber、NSarray、Bool；
    NSString *jsonStr = @"{"name":"Zhangsan","age":20,"dog":{"name":["XiaoHei", "XiaoQiang"]}}";
    NSData *data = [jsonStr dataUsingEncoding:NSUTF8StringEncoding];
    //将Json数据转化为OC的对象
    NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments error:nil];
//    打印字典
    NSLog(@"%@", dict);
//    打印字典内键为“dog”的内容
    NSLog(@"%@", dict[@"dog"][@"name"]);
    
//    创建字典对象，并用字典dict的dog字典对其初始化
    
    NSDictionary *dogDict = [dict objectForKey:@"dog"];
//    把字典里的name键所对应内容放入数组内
    NSArray *array = [dogDict objectForKey:@"name"];
    NSLog(@"%@", array);
    
//    创建字符串并把数组的第一个元素对其进行初始化
    NSString *name = [array objectAtIndex:0];
    NSLog(@"%@", name);
//  创建一个NSNumber对象，并将dict中age所指向的内容对其进行初始化
    NSNumber *num = [dict objectForKey:@"age"];
    NSLog(@"%@", num);

    
    //字典、数组、数值、字符串
    NSArray *arr = @[@123, @"123", @{@"name": @"Lisi", @"age": @30}];
    //将OC的对象转化为Json数据
    NSData *jsonData = [NSJSONSerialization dataWithJSONObject:arr options:NSJSONWritingPrettyPrinted error:nil];
    NSString *str = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
    NSLog(@"%@", str);
    
//    将str写入"/Users/apple/Desktop/test.json"内
    [str writeToFile:@"/Users/apple/Desktop/test.json" atomically:YES encoding:NSUTF8StringEncoding error:nil];
}

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

@end

2.xml解析

<>表示标签，开标签和闭标签

1）添加解析工具

2）.引入头文件

3）.开始解析

#import "ViewController.h"
#import "XMLDictionary.h"

@interface ViewController ()
            

@end

@implementation ViewController
            
- (void)viewDidLoad {
    [super viewDidLoad];
    NSString  *xmlstr=@"<person sex="female"><firstname>Anna</firstname><lastname>Smith</lastname></person><person><sex>female</sex><firstname>Anna</firstname><lastname>Smith</lastname></person>;";
    
    //xml 都是转化为字典
    NSDictionary *dic=[NSDictionary dictionaryWithXMLString:xmlstr];
    NSLog(@"%@",dic);
    NSLog(@"%@",[dic objectForKey:@"firstname"]);
    


    
    // Do any additional setup after loading the view, typically from a nib.
}

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

@end

3.HTML解析

1）1.引入解析工具

2）添加如图所示框架

3）在build setting中加入"/usr/include/libxml2" 到 "header search paths"

 

4）引入头文件

#import "ViewController.h"
#import "HTMLParser.h"
#import "HTMLNode.h"
#import <libxml/HTMLtree.h>

5）开始解析

#import "ViewController.h"
#import "HTMLParser.h"
#import "HTMLNode.h"
#import <libxml/HTMLtree.h>

@interface ViewController ()
            

@end

@implementation ViewController
            
- (void)viewDidLoad {
    [super viewDidLoad];
    NSError *error=nil;
    
    NSString *html=[[NSString alloc]initWithContentsOfURL:[NSURL URLWithString:@"http://dict.youdao.com/search?le=eng&q=interaction&keyfrom=dict.top"] encoding:NSUTF8StringEncoding error:nil];
//    将HTML转为oc语言
    HTMLParser *parser=[[HTMLParser alloc]initWithString:html error:nil];
    if (error) {
        NSLog(@"error:%@",error);
        return;
    }
//    NSLog(@"%@",html);
    //找body
    HTMLNode *bodeNode=[parser body];
    //根据class找到一个子节点
    HTMLNode *htmlnode=[bodeNode findChildOfClass:@"keyword"];
    //打印htmlnode里面的内容
    NSLog(@"%@",[htmlnode contents]);
    HTMLNode *html1=[bodeNode findChildOfClass:@"trans-container"];
    NSArray *array=[html1 findChildTags:@"li" ];
    //将标签里面的东西例举出来
    for(HTMLNode *aa in array){
        NSLog(@"%@",[aa contents]);
    }

四、对象之间的传参

1）第一个页面传到第二个页面

在ViewController.m里面

#import "ViewController.h"
#import "SecondViewController.h"

@interface ViewController ()
{
//设置全局变量
    int i;
   
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    UIButton *btn=[UIButton buttonWithType:UIButtonTypeSystem];
    btn.frame=CGRectMake(100, 200, 100, 40);
    btn.backgroundColor=[UIColor greenColor];
    [btn addTarget:self action:@selector(didclicked) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
     i=10;   
}

-(void)didclicked{

    SecondViewController *sec=[[SecondViewController alloc]init];
//    将i的值赋值给第一个页面的属性t
    sec.t=i;
    [self presentViewController:sec animated:YES completion:nil];
}

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

@end

在SecondViewController.h中

#import <UIKit/UIKit.h>
@interface SecondViewController : UIViewController
//设置属性
@property int t;
@end

在SecondViewController.m中

#import "SecondViewController.h"

@interface SecondViewController ()@end

@implementation SecondViewController

- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    UIButton *btn=[UIButton buttonWithType:UIButtonTypeSystem];
    btn.backgroundColor=[UIColor orangeColor];
    btn.frame=self.view.bounds;
    [btn addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
    //打印第一个页面传来的t值
    NSLog(@"%d",_t);
}
-(void)back
{
    [self dismissViewControllerAnimated:YES completion:nil];
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}


@end

2.将第二个页面的值传给第一个页面

在ViewController.h里面

#import <UIKit/UIKit.h>
@interface ViewController : UIViewController
//设置属性
@property int n;
@end

在ViewController.m里面

#import "ViewController.h"
#import "SecondViewController.h"

@interface ViewController ()@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    UIButton *btn=[UIButton buttonWithType:UIButtonTypeSystem];
    btn.frame=CGRectMake(100, 200, 100, 40);
    btn.backgroundColor=[UIColor greenColor];
    [btn addTarget:self action:@selector(didclicked) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
}

-(void)didclicked{

    SecondViewController *sec=[[SecondViewController alloc]init];
//    将第二个页面的对象的属性指向第一个页面，实现第二个页面的值传到第一页面必须的留下的地址
    sec.viewctr=self;
    [self presentViewController:sec animated:YES completion:nil];
}

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

@end

在SecondViewController.h中

#import <UIKit/UIKit.h>
#import "ViewController.h"
@class ViewController;
@interface SecondViewController : UIViewController
//创建第二个页面的一个属性，使其能够使用这个类的属性，能够实现的第二个页面传到第一个页面
@property ViewController *viewctr;
//设置属性
@property int m;
@end

在SecondViewController.m中

#import "SecondViewController.h"

@interface SecondViewController ()
{
//设置全局变量
    int k;

}
@end

@implementation SecondViewController

- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
 

    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    UIButton *btn=[UIButton buttonWithType:UIButtonTypeSystem];
    btn.backgroundColor=[UIColor orangeColor];
    btn.frame=self.view.bounds;
    [btn addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
    k=5;
//    将k的值赋值给给第一个页面的n
    self.viewctr.n=k;
    //打印传给第一个页面的值
    NSLog(@"n=%d",self.viewctr.n);
    
}
-(void)back
{
    [self dismissViewControllerAnimated:YES completion:nil];

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

3.通过协议传参

在ViewController.h里面

#import "ViewController.h"
#import "SecondViewController.h"

@interface ViewController ()<translatedelegate>
{
    SecondViewController *secondCtrl ;
    int k;
}
            

@end

@implementation ViewController
            
- (void)viewDidLoad {
    [super viewDidLoad];
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];
    btn.frame = CGRectMake(10, 100, 100, 40);
    [btn setTitle:@"按钮" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(didClick) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
    
    
    // Do any additional setup after loading the view, typically from a nib.
}
- (void)didClick
{
    secondCtrl = [[SecondViewController alloc] init];
    //在两个协议间建立联系
    secondCtrl.delegate = self;
    [self presentViewController:secondCtrl animated:YES completion:nil];
}
- (int)fetchValue:(int)value
{
    //传值
    k=value;
    NSLog(@"+++second%@---%d",secondCtrl, k);
    return 123;
    
    
    
}


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

@end

在SecondViewController.h中

#import <UIKit/UIKit.h>
//定义协议
@protocol translatedelegate
@optional
- (int)fetchValue:(int)value;
@end


@interface SecondViewController : UIViewController
//定义指针用来指向实现协议的对象
@property (nonatomic,weak)id<translatedelegate>delegate;
@property (nonatomic, assign) int value;
@end

在SecondViewController.m中

#import "SecondViewController.h"

@interface SecondViewController ()
{
    int k;
}

@end

@implementation SecondViewController

- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        self.view.backgroundColor=[UIColor whiteColor];
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];
    btn.frame = CGRectMake(10, 100, 100, 40);
    [btn setTitle:@"按钮" forState:UIControlStateNormal];
    [btn addTarget:self action:@selector(didClick) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
    // Do any additional setup after loading the view.
}

- (void)didClick
{

    _value=30;
    //使用指针来调用协议里面的方法
    [self.delegate fetchValue:_value];
    [self dismissViewControllerAnimated:YES completion:nil];
}

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

@end