objective-c最后一节笔记

objective-c最后一节笔记

 

 

// NSDate *date=[NSDate date];//这里的时间是GMT时间是。格林尼标准时间和北京时间相差8个小时，因为北京在东八区。

// NSDate *date1=[NSDate dateWithTimeInterval:60*60*8 sinceDate:date];//加8个小时

// 字典加数组操作

// NSArray *keys = [@"one two three" componentsSeparatedByString:@" "];

// NSArray *value = [@"two bravo a" componentsSeparatedByString:@" "];

// NSDictionary *dic = [[NSDictionary alloc]initWithObjects:value forKeys:keys];

// NSLog(@"%s",[[dic description] UTF8String]);//返回类型是NSString;

// NSLog(@"%@",[dic objectForKey:@"one"]);

// NSLog(@"%@",keys);

// [dic release];

// NSURL *url=[[NSURL alloc]initWithString:@"http://www.baidu.com"];

// NSString *astring = [[NSString alloc] initWithContentsOfURL:url];

// NSLog(@"astring:%@",astring);

// NSMutableArray *arry=[[NSMutableArray alloc ]initWithObjects:@"987",@"654",@"321",@"000", nil];

//

// for (NSString *element in arry ) {

// NSLog(@"element:%@",element);

// }

//创建文件管理器；

// NSFileManager *filem=[NSFileManager defaultManager];

// //指定要存档的路径

// NSString *path=[NSString stringWithFormat: @"/Users/ibokan/Desktop/a6.txt"];

// // NSString *path1=[NSString stringWithFormat:@"/Users/ibokan/Desktop/a1.txt"];

// //添加字符串信息；

// NSMutableString *str=[NSMutableString stringWithFormat:@"abc"];

// //2个属性间用-分割。

// [str appendFormat:@"\n"];

// [str appendFormat:@"%d",55];

// [str appendFormat:@"-"];

// [str appendFormat:@"%d",333];

// //将字符串对象转换为NSData类型的对象。

// NSData *data=[str dataUsingEncoding:NSUTF8StringEncoding];

//

// if ([filem fileExistsAtPath:path]) {

// NSLog(@"文件已经存在，不能再创建。");

// }

// else{

// [filem createFileAtPath:path contents:data attributes:nil];

// //[filem

// }

// NSString *s=[NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];

// NSArray *array=[s componentsSeparatedByString:@"\n"];

// NSString *a1=[array objectAtIndex:0];

// NSString *a2=[array objectAtIndex:1];

// NSLog(@"a1==%@,a2==%@",a1,a2);

//

// //[filem removeItemAtPath:@"/Users/ibokan/Desktop/a6.txt" error:nil];

// //获取指定路径的文件数据

// NSString *file=[NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];

// //添加指定的信息

// NSString *addFile=[file stringByAppendingFormat:@"hello"];

// //把添加的信息写入文件。

// [addFile writeToFile:path atomically:NO encoding:NSUTF8StringEncoding error:nil];

// NSLog(@"addFile==%@",addFile);

// //用NSData类型接受网络数据，可以提快速度。

// NSData *dt=[NSData dataWithContentsOfFile:path];

// //转换为NSString类型。

// NSString *dtString =[NSString stringWithCString:[dt bytes] encoding:NSUTF8StringEncoding];

// NSString *addt=[dtString stringByAppendingFormat:@"piaoliang"];

// [addt writeToFile:path atomically:NO encoding:NSUTF8StringEncoding error:nil];

// //新建一个url

// NSURL *url=[NSURL URLWithString:@"http://api.hudong.com/iphonexml.do?type=focus-c"];

// //新建一个请求

// NSURLRequest *request=[NSURLRequest requestWithURL:url];

// //新建连接

// [NSURLConnection connectionWithRequest:request delegate:self];

//

// NSLog(@"NSURLConnection完成");

 

 

注意到writeToFile:方法中的单词atomically了吗？这种调用有什么负面作用吗？没有。atomically:参数的值为BOOL类型，用于通知Cocoa是否应该首先将文件内容保存在临时文件中，当文件成功保存后，在将该临时文件和原始文件交换。这是一种安全机制：如果在保存过程中出现意外，不会破坏原始文件，但这种安全机制需要付出一定的代价：在保存过程中，由于原始文件仍然保存在磁盘中，所以需要使用双倍的磁盘空间。除非保存的文件非常大，将会占用用户硬盘的空间，否则应该自动保存文件。

 

 

 

 

 

#import "ViewController.h"

#import "GDataXMLNode.h"

#import "JSON.h"

@implementation ViewController

@synthesize finaldata=_finaldata;

- (void)didReceiveMemoryWarning

{

[superdidReceiveMemoryWarning];

// Release any cached data, images, etc that aren't in use.

}

 

#pragma mark - View lifecycle

-(void) connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{

NSLog(@"连接开始");

//初始化_finaldata

_finaldata=[[NSMutableDataalloc]initWithCapacity:1024];

}

-(void) connection:(NSURLConnection *)connection didReceiveData:(NSData *)data

{

NSLog(@"接受数据");

//每次回调函数将接受到的data附加到finaldata

[self.finaldata appendData:data];

}

-(void) connectionDidFinishLoading:(NSURLConnection *)connection{

//创建图片view

UIImageView *view=[[UIImageViewalloc]initWithFrame:CGRectMake(0, 100, 320, 320)];

//创建图片

UIImage *image=[UIImage imageWithData:self.finaldata];

//图片放入view

view.image=image;

[self.view addSubview:view];

 

//测试下载图片到本地

//下载的目录

NSString *path=[[NSBundlemainBundle]bundlePath];

NSString *urlname=@"http://best50.cn:8080/update/10/food/72.jpg";

// NSLog(@"%@",[urlname lastPathComponent]);

// NSLog(@"%@",path);

//具体路径

NSString *filepath=[path stringByAppendingPathComponent:[urlname lastPathComponent]];

NSFileManager *fm=[NSFileManagerdefaultManager];

if([fm createFileAtPath:filepath contents:self.finaldataattributes:nil]){

NSLog(@"下载成功");

}

}

-(void) loadImage:(id) sender{

//测试异步连接

//1创建url对象

//http://best50.cn:8080/update/10/food/72.jpg

NSURL *url=[NSURLURLWithString:@"http://image.baidu.com/i?ct=503316480&z=0&tn=baiduimagedetail&cl=2&cm=1&sc=0&lm=-1&fr=ala2&pn=2&rn=1&di=224720221900&ln=1978&word=%D5%C5%BA%AC%D4%CF#pn8&-1&di379336959350&objURLhttp%3A%2F%2Fmy.dili360.com%2Fattachments%2F2009%2F02%2F173376_20090218183959523el.jpg&fromURLhttp%3A%2F%2Fmy.dili360.com%2Fhome%2Fspace.php%3Fuid%3D173376%26do%3Dalbum%26picid%3D34195&W1022&H766&T8602&S116&TPjpg"];

//2创建请求对象

NSURLRequest *request=[NSURLRequestrequestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheDatatimeoutInterval:10];

//3发起异步请求,并设置代理

[NSURLConnectionconnectionWithRequest:request delegate:self];

}

-(void)showImage:(id)sender{

//测试异步连接

//创建url对象

NSURL *url1=[NSURLURLWithString:@"http://image.baidu.com/i?ct=503316480&z=0&tn=baiduimagedetail&cl=2&cm=1&sc=0&lm=-1&fr=ala2&pn=2&rn=1&di=224720221900&ln=1978&word=%D5%C5%BA%AC%D4%CF#pn8&-1&di379336959350&objURLhttp%3A%2F%2Fmy.dili360.com%2Fattachments%2F2009%2F02%2F173376_20090218183959523el.jpg&fromURLhttp%3A%2F%2Fmy.dili360.com%2Fhome%2Fspace.php%3Fuid%3D173376%26do%3Dalbum%26picid%3D34195&W1022&H766&T8602&S116&TPjpg"];

//这个路径不知道为什么不能用。

//创建请求对象。

NSURLRequest *request1=[NSURLRequestrequestWithURL:url1 cachePolicy:NSURLRequestReloadIgnoringLocalCacheDatatimeoutInterval:122];

//发起异步请求。并设置代理。

[NSURLConnectionconnectionWithRequest:request1 delegate:self];

 

}

 

- (void)viewDidLoad

{

[superviewDidLoad];

 

// UIButton *btn=[UIButton buttonWithType:1];

// btn.frame=CGRectMake(0, 0, 100, 80);

// [btn setTitle:@"piaoliang" forState:UIControlStateNormal];

// [btn addTarget:self action:@selector(showImage:) forControlEvents:UIControlEventTouchUpInside];

// [self.view addSubview:btn];

 

 

//1测试get同步连接

//1创建url对象

//http://api.hudong.com/iphonexml.do?type=focus-c

// NSURL *url=[NSURL URLWithString:@"http://api.hudong.com/iphonexml.do?type=focus-c"];

// //2创建请求对象

// NSURLRequest *request=[NSURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:10];

// //3创建响应和错误指针对象

// NSHTTPURLResponse *response=nil;

// NSError *error=nil;

// //4创建连接对象发起同步连接，并将返回数据存入data

// NSData *data=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

// //5打印请求status，和错误status

// NSLog(@"response=%@",[NSHTTPURLResponse localizedStringForStatusCode:[response statusCode]]);

// NSLog(@"error=%@",[error localizedDescription]);

// //6将内容打印输出

// NSLog(@"data=%@",[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding]);

 

//2测试post同步连接

//1创建url对象

//http://api.hudong.com/iphonexml.do?type=focus-c

// NSURL *url=[NSURL URLWithString:@"http://api.hudong.com/iphonexml.do?type=focus-c"];

// //2创建请求对象

// NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:url cachePolicy:NSURLRequestReloadIgnoringCacheData timeoutInterval:10];

// //2.5设置请求为post

// [request setHTTPMethod:@"post"];

// //3创建响应和错误指针对象

// NSHTTPURLResponse *response=nil;

// NSError *error=nil;

// //4创建连接对象发起同步连接，并将返回数据存入data

// NSData *data=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

// //5打印请求status，和错误status

// NSLog(@"response=%@",[NSHTTPURLResponse localizedStringForStatusCode:[response statusCode]]);

// NSLog(@"error=%@",[error localizedDescription]);

// //6将内容打印输出

// NSLog(@"data=%@",[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding]);

 

//3测试异步连接请求图片并下载到本地

UIButton *btn=[UIButtonbuttonWithType:1];

btn.frame=CGRectMake(0, 0, 100, 80);

[btn setTitle:@"点一点"forState:UIControlStateNormal];

[btn addTarget:selfaction:@selector(loadImage:) forControlEvents:UIControlEventTouchUpInside];

[self.view addSubview:btn];

 

//4测试xml本地文件解析

// NSString *path=[[NSBundle mainBundle]bundlePath];

// NSString *filepath=[path stringByAppendingPathComponent:@"Student.xml"];

// NSString *str1=[NSString stringWithContentsOfFile:filepath encoding:NSUTF8StringEncoding error:nil];

// NSLog(@"%@",str1);

// //解析文档

// //1创建要解析的XML文档对象

// GDataXMLDocument *doc=[[GDataXMLDocument alloc]initWithXMLString:str1 options:0 error:nil];

// //2获取要解析文档的root元素

// GDataXMLElement *root=doc.rootElement;

// //3从根元素获取元素

// NSArray *docList=[root elementsForName:@"student"];

// NSLog(@"docList==%@",docList);

// //4获取第一个student元素

// GDataXMLElement *de1=[docList objectAtIndex:0];

// NSLog(@"de1==%@",de1);

// //5获取子元素

// NSArray *stuAry1=[de1 children];

// NSLog(@"stuAry1==%@",stuAry1);

// //获取每个子元素

// for (GDataXMLElement *e in stuAry1) {

// NSLog(@"%@=%@",e.name,e.stringValue);

// }

 

//5json解析测试，测试读取本地JSON文件内容

// NSString *jpath=[path stringByAppendingPathComponent:@"student.json"];

// NSString * strJson = [NSString stringWithContentsOfFile:jpath encoding:NSUTF8StringEncoding error:nil];

// NSArray * arr= [strJson JSONValue];

// for (int i=0; i<2; i++) {

// NSDictionary * dic = [arr objectAtIndex:i];

// for(id s in dic)

// {

// NSLog(@"%@=%@",s,[dic objectForKey:s]);

// }

// }

 

}

 

- (void)viewDidUnload

{

[superviewDidUnload];

// Release any retained subviews of the main view.

// e.g. self.myOutlet = nil;

}

 

- (void)viewWillAppear:(BOOL)animated

{

[super viewWillAppear:animated];

}

 

- (void)viewDidAppear:(BOOL)animated

{

[super viewDidAppear:animated];

}

 

- (void)viewWillDisappear:(BOOL)animated

{

[superviewWillDisappear:animated];

}

 

- (void)viewDidDisappear:(BOOL)animated

{

[superviewDidDisappear:animated];

}

 

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation

{

// Return YES for supported orientations

return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);

}

 

@end