4_1网络学习第一天后感--网络数据下载

-(void)testNSURLConnectionSyncDownloadData{    //限免页面接口    NSString *urlString=@"http://iappfree.candou.com:8080/free/applications/limited?currency=rmb&page=1&category_id=";        //发送同步URL请求    //NSURLRequest URL请求对象    NSURL *url=[NSURL URLWithString:urlString];    NSURLRequest *request=[NSURLRequest requestWithURL:url];    NSError *error=nil;    NSData *data=[NSURLConnection sendSynchronousRequest:request returningResponse:nil error:&error];    if (error==nil) {        NSString *str=[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];        NSLog(@"str = %@",str);    }    else {        NSLog(@"下载失败");    }}

-(void)testNSURLConnectionAsyncDownloadData{    _data=[[NSMutableData alloc]init];    //限免页面接口    NSString *urlString=@"http://iappfree.candou.com:8080/free/applications/limited?currency=rmb&page=1&category_id=";    //发起一个异步URL请求    //异步：执行了方法之后，开始下载    _connection=[[NSURLConnection alloc]initWithRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:urlString]] delegate:self startImmediately:YES];    }//下面是<NSURLConnectionDataDelegate>代理方法//接收到服务器响应执行-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{    NSLog(@"接收到服务器响应执行");}//接收到数据的时候执行//注意：当数据比较大，可能会多次执行-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{    [_data appendData:data];}//当数据下载完成了-(void)connectionDidFinishLoading:(NSURLConnection *)connection{//    NSLog(@"str =%@",[[NSString alloc]initWithData:_data encoding:NSUTF8StringEncoding]);        //解析JSON (把JSON转化为NSArray或NSDictionary    NSDictionary *dict=[NSJSONSerialization JSONObjectWithData:_data options:NSJSONReadingMutableContainers error:nil];    NSArray *appList=dict[@"applications"];    for (NSDictionary *appDict in appList) {        NSLog(@"name = %@",appDict[@"name"]);    }}//下载失败-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{    NSLog(@"error =%@",error);}

#import <Foundation/Foundation.h>@interface ZJHttPRequset : NSObject//data用来保存下载的数据@property (nonatomic,copy) NSMutableData *data;//传人一个网站，下载完成之后，执行target中action的方法-(void)requestWithUrl:(NSString *)url target:(id)target action:(SEL)action;@end

#import "ZJHttpRequset.h"#import "AppModel.h"//消除performSelector的警告#pragma clang diagnostic ignored "-Warc-performSelector-leaks"//类扩展，有些实例变量内部使用，不想放在头文件，就可以放在类扩展里面。@interface ZJHttpRequset ()<NSURLConnectionDataDelegate>{    NSURLConnection *_connection;        //用来保存存进来的url  target action    NSString *_url;    id _target;    SEL _action;}@end@implementation ZJHttpRequset-(void)requestWithUrl:(NSString *)url target:(id)target action:(SEL)action{    //保存存进来的变量    _url=url;    _target=target;    _action=action;        //记住要初始化data！！！    _data=[[NSMutableData alloc]init];    //发起异步URL请求    _connection=[[NSURLConnection alloc]initWithRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:url]] delegate:self startImmediately:YES];}//NSURLConnection代理方法//接收数据-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{    [_data appendData:data];}//下载完成了，执行方法-(void)connectionDidFinishLoading:(NSURLConnection *)connection{    if (_target&&[_target respondsToSelector:_action]) {        [_target performSelector:_action withObject:self];    }    //这里面的Object就是这个类本身，目的是把接收到的data传递}

@implementation ViewController- (void)viewDidLoad{    [super viewDidLoad];    //数据接口    NSString *urlString=@"http://iappfree.candou.com:8080/free/applications/limited?currency=rmb&page=1&category_id=";    //初始化数组（tabelView的数据总数组)    _dataArray =[NSMutableArray array];    //初始化自封装好的NSURLConnection类    _request=[[ZJHttpRequset alloc]init];    [_request requestWithUrl:urlString target:self action:@selector(dealDownloadFinish:)];        //创建表视图    [self createTableView];}//接收完成之后会触发的方法（在自封装的URL类中 使用PerformSelector）-(void)dealDownloadFinish:(ZJHttpRequset *)request{    //JSON解析，（获得的是数组还是字典，需要在JASON软件中查看）    NSDictionary *dict=[NSJSONSerialization JSONObjectWithData:request.data options:NSJSONReadingMutableContainers error:nil];    NSArray *appList=dict[@"applications"];    //利用数据模型保存网络接口下的数据，然后把模型添加到tableView总数组    for (NSDictionary *appDict in appList) {                AppModel *model=[[AppModel alloc]initWithDict:appDict];                [_dataArray addObject:model];    }    //下载完数据，更新了总数组，一定要刷新tableview！！！    [_tableView reloadData];}

//第一步：初始化，从网络接口下载数据-(void)createScrollView{    _allData1=[NSMutableArray array];    //陈奕迅网络接口    NSString *urlString=@"http://mapi.damai.cn/hot201303/nindex.aspx?cityid=0&source=10099&version=30602";    _request1 =[[LCHttpRequest alloc]init];    [_request1 requestUrl:urlString withTarget:self andAction:@selector(scrollViewDownload:)];    }//第二步：下载完成后触发的方法，把下载好的data 存入总数组-(void)scrollViewDownload:(LCHttpRequest *)request{    NSArray *arr=[NSJSONSerialization JSONObjectWithData:request.data options:NSJSONReadingMutableContainers error:nil];    for (NSDictionary *dict in arr) {        NSString *str=dict[@"Pic"];        [_allData1 addObject:str];    }    [self loadImage];}//第三步:根据下载的总数组，改变ScrollView的contenSize 同时设置其imageView-(void)loadImage{    _scrollView.contentSize=CGSizeMake(320*_allData1.count, 0);    for (int i=0; i<_allData1.count; i++) {        UIImageView *imageView=[[UIImageView alloc]initWithFrame:CGRectMake(320*i, 0, 320, 165)];        NSString *str= _allData1[i];        [imageView setImageWithURL:[NSURL URLWithString:str]];        [_scrollView addSubview:imageView];    }    //设置pageControl     _pageControl.numberOfPages=_allData1.count;    _pageControl.enabled=NO;    [self.view bringSubviewToFront:_pageControl];    _pageControl.pageIndicatorTintColor=[UIColor redColor];    //启动定时器，让scroView滑动    [NSTimer scheduledTimerWithTimeInterval:3.0 target:self selector:@selector(scrollViewMove) userInfo:nil repeats:YES];}//定时器触发的方法-(void)scrollViewMove{    CGPoint pp=_scrollView.contentOffset;    if (pp.x==320*(_allData1.count-1)) {        pp.x=0;        _scrollView.contentOffset=pp;    }    else{        pp.x+=320;    [UIView animateWithDuration:2.0 animations:^{        _scrollView.contentOffset=pp;    }];    }}//<UIScrllViewDelegate> 代理方法让pageControl跟着移动-(void)scrollViewDidScroll:(UIScrollView *)scrollView{    int page =scrollView.contentOffset.x/320;    _pageControl.currentPage=page;}