ios 学习笔记 7 之 protocol

   

   object-c中的protocol有点类似于c#中的委托和接口，下面用实例来说明：

   从远程下载图片到UIImage,然后再180度转换图片

#import <Foundation/Foundation.h>
#define TIMEOUT_SEC        20.0

@interface TSHttpClient : NSObject {
    NSURLConnection *connection;
    NSMutableData *recievedData;
    int statusCode;    
    BOOL contentTypeIsXml;
    
    int rate_limit;
    int rate_limit_remaining;
    NSDate *rate_limit_reset;
}

- (void)requestGET:(NSString*)url;
- (void)requestPOST:(NSString*)url body:(NSString*)body;
- (void)requestGET:(NSString*)url username:(NSString*)username password:(NSString*)password;
- (void)requestPOST:(NSString*)url body:(NSString*)body username:(NSString*)username password:(NSString*)password;

- (void)cancel;

- (void)requestSucceeded;
- (void)requestFailed:(NSError*)error;

- (void)reset;

@property (readonly) NSMutableData *recievedData;
@property (readonly) int statusCode;

@end

#import "TSHttpClient.h"

@implementation TSHttpClient

@synthesize recievedData, statusCode;

- (id)init {
    if (self = [super init]) {
        [self reset];
    }
    return self;
}

- (void)dealloc {
    NSLog(@"NTLNHttpClient#dealloc");
    [connection release];
    [recievedData release];
    [rate_limit_reset release];
    [super dealloc];
}

+ (NSString*)stringEncodedWithBase64:(NSString*)str
{
    static const char *tbl = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    
    const char *s = [str UTF8String];
    int length = [str length];
    char *tmp = malloc(length * 4 / 3 + 4);
    
    int i = 0;
    int n = 0;
    char *p = tmp;
    
    while (i < length) {
        n = s[i++];
        n *= 256;
        if (i < length) n += s[i];
        i++;
        n *= 256;
        if (i < length) n += s[i];
        i++;
        
        p[0] = tbl[((n & 0x00fc0000) >> 18)];
        p[1] = tbl[((n & 0x0003f000) >> 12)];
        p[2] = tbl[((n & 0x00000fc0) >>  6)];
        p[3] = tbl[((n & 0x0000003f) >>  0)];
        
        if (i > length) p[3] = '=';
        if (i > length + 1) p[2] = '=';
        
        p += 4;
    }
    
    *p = '\0';
    
    NSString *ret = [NSString stringWithCString:tmp];
    free(tmp);
    
    return ret;
}

+ (NSString*) stringOfAuthorizationHeaderWithUsername:(NSString*)username password:(NSString*)password {
    return [@"Basic " stringByAppendingString:[TSHttpClient stringEncodedWithBase64:
                                               [NSString stringWithFormat:@"%@:%@", username, password]]];
}

- (NSMutableURLRequest*)makeRequest:(NSString*)url {
    NSString *encodedUrl = (NSString*)CFURLCreateStringByAddingPercentEscapes(
                                                                              NULL, (CFStringRef)url, NULL, NULL, kCFStringEncodingUTF8);
    NSMutableURLRequest *request = [[[NSMutableURLRequest alloc] init] autorelease];
    [request setURL:[NSURL URLWithString:encodedUrl]];
    [request setCachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData];
    [request setTimeoutInterval:TIMEOUT_SEC];
    [request setHTTPShouldHandleCookies:FALSE];
    [encodedUrl release];
    return request;
}

- (NSMutableURLRequest*)makeRequest:(NSString*)url username:(NSString*)username password:(NSString*)password {
    NSMutableURLRequest *request = [self makeRequest:url];
    [request setValue:[TSHttpClient stringOfAuthorizationHeaderWithUsername:username password:password]
   forHTTPHeaderField:@"Authorization"];
    return request;
}

- (void)reset {
    [recievedData release];
    recievedData = [[NSMutableData alloc] init];
    [connection release];
    connection = nil;
    [rate_limit_reset release];
    rate_limit_reset = nil;
    
    statusCode = 0;    
    contentTypeIsXml = NO;
    
    rate_limit = 0;
    rate_limit_remaining = 0;
}

- (void)prepareWithRequest:(NSMutableURLRequest*)request {
    // do nothing (for OAuthHttpClient)
}

- (void)requestGET:(NSString*)url {
    [self reset];
    NSMutableURLRequest *request = [self makeRequest:url];
    [self prepareWithRequest:request];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
}

- (void)requestPOST:(NSString*)url body:(NSString*)body {
    [self reset];
    NSMutableURLRequest *request = [self makeRequest:url];
    [request setHTTPMethod:@"POST"];
    if (body) {
        [request setHTTPBody:[body dataUsingEncoding:NSUTF8StringEncoding]];
    }
    [self prepareWithRequest:request];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

- (void)requestGET:(NSString*)url username:(NSString*)username password:(NSString*)password {
    [self reset];
    NSMutableURLRequest *request = [self makeRequest:url username:username password:password];
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self startImmediately:YES];
}

- (void)requestPOST:(NSString*)url body:(NSString*)body username:(NSString*)username password:(NSString*)password {
    [self reset];
    NSMutableURLRequest *request = [self makeRequest:url username:username password:password];
    [request setHTTPMethod:@"POST"];
    if (body) {
        [request setHTTPBody:[body dataUsingEncoding:NSUTF8StringEncoding]];
    }
    connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];
}

- (void)cancel {
    [connection cancel];
    [self reset];
    [self requestFailed:nil];
}

- (void)requestSucceeded {
    // implement by subclass
}

- (void)requestFailed:(NSError*)error {
    // implement by subclass
}
/*
 -(void)connection:(NSURLConnection*)connection didReceiveAuthenticationChallenge:(NSURLAuthenticationChallenge*)challenge { 
 [[challenge sender] cancelAuthenticationChallenge:challenge]; 
 }    
 */

- (NSCachedURLResponse *)connection:(NSURLConnection *)connection willCacheResponse:(NSCachedURLResponse *)cachedResponse {
    return nil;
}

- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
        NSLog(@"didReceiveResponse");
    
    statusCode = [(NSHTTPURLResponse*)response statusCode];
    NSDictionary *header = [(NSHTTPURLResponse*)response allHeaderFields];
    
    contentTypeIsXml = NO;
    NSString *content_type = [header objectForKey:@"Content-Type"];
    if (content_type) {
        NSRange r = [content_type rangeOfString:@"xml"];
        if (r.location != NSNotFound) {
            contentTypeIsXml = YES;
        }
    }
    
    for (NSString *s in [header allKeys]) {
     NSLog(@"header: %@", s);
     }
         
    NSString *rateLimit = [header objectForKey:@"X-Ratelimit-Limit"];
    NSString *rateLimitRemaining = [header objectForKey:@"X-Ratelimit-Remaining"];
    NSString *rateLimitReset = [header objectForKey:@"X-Ratelimit-Reset"];
    if (rateLimit && rateLimitRemaining) {
        rate_limit = [rateLimit intValue];
        rate_limit_remaining = [rateLimitRemaining intValue];
        rate_limit_reset = [[NSDate dateWithTimeIntervalSince1970:[rateLimitReset intValue]] retain];
        NSLog(@"rate_limit: %d rate_limit_remaining:%d",rate_limit, rate_limit_remaining);
    }
}

- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
    NSLog(@"didReceiveData");
    [recievedData appendData:data];
}

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
    NSLog(@"connectionDidFinishLoading");
    [self requestSucceeded];
    [self reset];
}

- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError*) error {
    NSLog(@"didFailWithError");
    [self requestFailed:error];
    [self reset];
}

@end

#import <Foundation/Foundation.h>
#import "TSHttpClient.h"

@class TSMallClient;

@protocol TSClientDelegate
//请求开始
- (void)tsClientBegin:(TSMallClient*)sender;
//请求结束
- (void)tsClientEnd:(TSMallClient*)sender;
//请求成功
- (void)tsClientSucceeded:(TSMallClient*)sender messages:(NSArray*)messages;
//请求失败
- (void)tsClientFailed:(TSMallClient*)sender;
@end

@interface TSMallClient : TSHttpClient
{
    //委托
    NSObject<TSClientDelegate> *delegate;
}

@property (readwrite, retain) NSObject<TSClientDelegate> *delegate;

@end


@property (readwrite, retain) NSObject<TSClientDelegate> *delegate;


@end

#import "TSMallClient.h"

@implementation TSMallClient
@synthesize delegate;

- (void)requestSucceeded {
    if (statusCode == 200) {
        [delegate tsClientSucceeded:self messages:nil];
    }
}

-(void) dealloc
{
    [delegate release];
    [super dealloc];
}

@end

#import <UIKit/UIKit.h>
#import "TSMallClient.h"

@interface TSImg : UIView
{
    UIImage *img;
    UIImageView *imgviews;
    //下载指示器
    UIActivityIndicatorView  *indicator;
}

@end

#import "TSImg.h"

@implementation TSImg
#define SizeAcitivityIndicator        20.0

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        img=[UIImage imageNamed:@"none.gif"];
        
        UILabel *lb=[[UILabel alloc]init];
        [lb setText:@"加载图片"];
        [lb setFrame:CGRectMake(50, 10, 100, 50)];
        imgviews=[[UIImageView alloc]initWithFrame:[[UIScreen mainScreen]applicationFrame]];
        imgviews.image=img;
        imgviews.bounds=CGRectMake(0, 150, 320, 320);
        
        indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
        //位于imgviews中间
        indicator.frame = CGRectMake((imgviews.frame.size.width - SizeAcitivityIndicator) / 2.0, (imgviews.frame.size.height - SizeAcitivityIndicator) / 2.0+150, SizeAcitivityIndicator, SizeAcitivityIndicator);
        indicator.hidesWhenStopped = YES;
        
        [imgviews addSubview:indicator];
        [indicator startAnimating];
        
        [self addSubview:imgviews];
        [self addSubview:lb];
        [lb release];
        [self downloadImg];
    }
    return self;
}

//下载图片
-(void) downloadImg
{
    TSMallClient *tmc=[[[TSMallClient alloc]init]autorelease];
    tmc.delegate=(NSObject<TSClientDelegate>*)self;
    [tmc requestGET:@"http://www.yishimai.com/ios/protocol/mountain.jpg"];
   
    
}

//下载完成后水平转180度
- (void)tsClientSucceeded:(TSHttpClient*)sender messages:(NSArray*)messages
{
    
    [img release];
    img = [[UIImage alloc] initWithData:sender.recievedData]; 
    imgviews.image=img;
    [indicator performSelector:@selector(stopAnimating)];
    
    UIViewAnimationTransition trans = UIViewAnimationTransitionFlipFromRight;
    
    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:1.0f];
    [UIView setAnimationTransition:trans forView:imgviews cache:YES];
    [imgviews exchangeSubviewAtIndex:0 withSubviewAtIndex:1];
    [UIView commitAnimations];
}

-(void) dealloc
{
    [indicator release];
    [imgviews release];
    [img release];
    [super dealloc];
}

@end