Iphone 自定义委托的问题

这是我第一次尝试编写自己的代理。我正在使用iOS5 Beta 7并编写委托函数

它应该做的是一个表（

MyTableController

）加载一个电视频道列表。这是一个包含键“logotype”的字典，该键是指向图像标识的URL。 我创建了名为“

Channel

”的类和名为“

ChannelDelegate

”的委托。现在，当我的表执行

cellforrowatinexpath

时，它将启动我的通道类并调用函数

getChannelImageForChannelId:externalreference:indexPath

。到目前为止还不错，现在我的channel类检查文件是否存在于本地，如果不存在，它将下载它（使用

ASIHttpRequest

）。而且，到目前为止还不错。现在，当ASIHttpRequest在requestDidFinish上返回时，它会在几个结果之后消失。我注意到文件确实被下载了，因为经过几次尝试后，它就像一个符咒一样工作，因此我的委托似乎工作正常

这是我的代码：
CellForRowAtIndexPath：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"CurrentChannelInfoCell";

    CurrentChannelInfoCell *cell = (CurrentChannelInfoCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil){
        NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:CellIdentifier owner:nil options:nil];

        for(id currentObject in topLevelObjects)
        {
            if([currentObject isKindOfClass:[CurrentChannelInfoCell class]])
            {
                cell = (CurrentChannelInfoCell *)currentObject;
                break;
            }
        }
    }


    NSArray *keys = [self.content allKeys];
    id channelId = [keys objectAtIndex:indexPath.row];
    NSDictionary *channel = [self.content objectForKey:channelId];

    int cId = [(NSString*)channelId intValue];

    [cell.textLabel setText:[channel objectForKey:@"name"]];
    [cell.channelImage setHidden:YES];

    Channel *theChannel = [[Channel alloc] init];
    [theChannel setDelegate:self];
    [theChannel getChannelImageForChannelId:cId externalRefference:[channel objectForKey:@"logotype"] indexPath:indexPath];

    return cell;
}

- (void)didRecieveImageForChannel:(NSString*)imagePath indexPath:(NSIndexPath*)indexPath
{
    NSLog(@"Did recieve the it.!");
}

我的委托，

ChannelDelegate.h

：

#import <Foundation/Foundation.h>

@class Channel;

@protocol ChannelDelegate <NSObject>

@optional
- (void)didRecieveImageForChannel:(NSString*)imagePath indexPath:(NSIndexPath*)indexPath;

@end

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

#import "Reachability.h"
#import "ASIHTTPRequest.h"
#import "ASINetworkQueue.h"
#import "ASIFormDataRequest.h"

@interface Channel : NSOperation <NSObject, ASIHTTPRequestDelegate>
{   
    ASINetworkQueue *networkQueue;

    // Called on the delegate (if implemented) when the request completes successfully.
    id <ChannelDelegate> delegate;

    SEL didRecieveImageForChannelSelector;
}

@property (strong, nonatomic) id delegate;
@property (assign) SEL didRecieveImageForChannelSelector;

- (void)getChannelImageForChannelId:(int)channelId externalRefference:(NSString*)url indexPath:(NSIndexPath*)indexPath;
- (id)delegate;

@end

Channel.m

：

#import "Channel.h"
#import <objc/runtime.h>

@implementation Channel

static char kAssociationKey;

@synthesize didRecieveImageForChannelSelector;
@synthesize delegate;

- (void)getChannelImageForChannelId:(int)channelId externalRefference:(NSString*)url indexPath:(NSIndexPath*)indexPath
{
    [self setDidRecieveImageForChannelSelector:@selector(didRecieveImageForChannel:indexPath:)];

    NSString *documentsPath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0];

    NSString *imagePath = [documentsPath stringByAppendingPathComponent:[NSString stringWithFormat:@"%d.gif", channelId]];
    BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:imagePath];

    if (fileExists)
    {
        NSLog(@"Downloaded image!");
        [[self delegate] performSelector:[self didRecieveImageForChannelSelector] withObject:imagePath withObject:indexPath];
    }
    else {
        NSLog(@"Need to fetch it.!");

        NSURL *theUrl = [NSURL URLWithString:url];

        ASINetworkQueue *newQueue = [[ASINetworkQueue alloc] init];
        [newQueue setRequestDidFinishSelector:@selector(channelImageFetched:)];
        [newQueue setRequestDidFailSelector:@selector(processFailed:)];
        [newQueue setDelegate:self];

        ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:theUrl];
        [request setTimeOutSeconds:60];
        [request setDownloadDestinationPath:imagePath];
        [newQueue addOperation:request];

        objc_setAssociatedObject(request, &kAssociationKey, indexPath, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

        [newQueue go];
    }
}

- (id)delegate
{
    id d = delegate;
    return d;
}

- (void)setDelegate:(id)newDelegate
{
    delegate = newDelegate;
}

// Handle process two
- (void)channelImageFetched:(ASIHTTPRequest *)request 
{
    NSLog(@"channelImageFetched!");


    NSIndexPath *indexPath = objc_getAssociatedObject(request, &kAssociationKey);
    NSString *imagePath = request.downloadDestinationPath;

    [[self delegate] performSelector:[self didRecieveImageForChannelSelector] withObject:imagePath withObject:indexPath];    

    NSLog(@"File downloaded!");
}

- (void) processFailed:(ASIHTTPRequest *)request
{   
    NSError *error = [request error];

    UIAlertView *errorView;

    errorView = [[UIAlertView alloc]
                 initWithTitle: NSLocalizedString(@"Whoops!", @"Errors")
                 //              message: NSLocalizedString(@"An error occured while preforming the request. Please try again.", @"Network error")
                 message: [error localizedDescription]
                 delegate: self
                 cancelButtonTitle: NSLocalizedString(@"Close", @"Errors") otherButtonTitles: nil];

    [errorView show];

    /*  NSDictionary *dictionary = [NSDictionary dictionaryWithObjectsAndKeys:
     [request error], @"Error",
     [request url], @"URL",
     [[NSDate alloc] init], @"timestamp", nil];

     [FlurryAPI logEvent:@"APNS-Could not fetch data." withParameters:dictionary timed:YES];
     */
}

@end

#导入“Channel.h”
#进口
@实施渠道
静态字符关联键；
@为通道选择器合成DID接收图像；
@综合代表；
-（void）getChannelImageForChannelId:（int）channelId外部引用：（NSString*）url索引XPath:（NSIndexPath*）索引XPath
{
[self-SetDidReceiveImageForChannel选择器：@selector（DidReceiveImageForChannel:indexPath:）]；
NSString*documentsPath=[NSSearchPathForDirectoriesInDomains（NSDocumentDirectory，NSUserDomainMask，YES）对象索引：0]；
NSString*imagePath=[documentsPath stringByAppendingPathComponent:[NSString stringWithFormat:@“%d.gif”，channelId]]；
BOOL fileExists=[[NSFileManager defaultManager]fileExistsAtPath:imagePath]；
如果（文件存在）
{
NSLog（@“下载的图像！”）；
[[self-delegate]性能选择器：[self-DiReceiveImageForChannelSelector]带对象：imagePath带对象：indexPath]；
}
否则{
NSLog（@“需要获取它！”；
NSURL*theUrl=[NSURL-URLWithString:url]；
ASINetworkQueue*newQueue=[[ASINetworkQueue alloc]init]；
[newQueue setRequestDidFinishSelector:@selector（channelImageFetched:）]；
[newQueue setRequestDidFailSelector:@selector（processFailed:）]；
[newQueue setDelegate:self]；
ASIHTTPRequest*request=[AsiHttpRequestWithURL:theUrl]；
[请求setTimeOutSeconds:60]；
[请求setDownloadDestinationPath:imagePath]；
[newQueue addOperation:request]；
objc_setAssociatedObject（请求、kAssociationKey、indexPath、objc_关联、保留、非原子）；
[newQueue go]；
}
}
-（id）代表
{
id d=代表；
返回d；
}
-（void）setDelegate:（id）newDelegate
{
delegate=newDelegate；
}
//处理流程二
-（void）channelImageFetched:（ASIHTTPRequest*）请求
{
NSLog（@“channelImageFetched！”）；
NSIndexPath*indexPath=objc_getAssociatedObject（请求和kAssociationKey）；
NSString*imagePath=request.downloadDestinationPath；
[[self-delegate]性能选择器：[self-DiReceiveImageForChannelSelector]带对象：imagePath带对象：indexPath]；
NSLog（@“文件已下载！”）；
}
-（void）processFailed:（ASIHTTPRequest*）请求失败
{   
n错误*错误=[请求错误]；
UIAlertView*错误视图；
errorView=[[UIAlertView alloc]
initWithTitle:NSLocalizedString（@“哎哟！”，@“错误”）
//消息：NSLocalizedString（@“执行请求时出错。请重试。”，@“网络错误”）
消息：[错误本地化描述]
代表：赛尔夫
取消按钮提示：NSLocalizedString（@“Close”，@“Errors”）其他按钮提示：nil]；
[错误视图显示]；
/*NSDictionary*dictionary=[NSDictionary dictionary WithObjectsAndKeys:
[请求错误]，@“错误”，
[请求url]，@“url”，
[[NSDate alloc]init]，@“timestamp”，nil]；
[FlurryAPI logEvent:@“APNS无法获取数据。”参数：dictionary timed:YES]；
*/
}
@结束

我收到的错误似乎不时不同，但这些似乎是我得到的错误：

2011-09-26 13:11:57.605电视体育【4541:ef03】完成
2011-09-26 13:11:57.609电视体育[4541:ef03]下载图片
2011-09-26 13:11:57.610电视体育[4541:ef03]确实收到了它
2011-09-26 13:11:57.613电视体育[4541:ef03]需要取回 如果
2011-09-26 13:11:57.616电视体育[4541:ef03]需要 把钥匙拿来
2011-09-26 13:11:57.618电视体育[4541:ef03] 我需要把它拿回来
2011-09-26 13:11:57.621 TVSOPERTS[4541:ef03]需要把它拿回来
2011-09-26 13:11:57.624电视体育[4541:ef03]需要取回它
2011-09-26 13:11:57.629电视体育[4541:ef03]需要取回 它
2011-09-26 13:11:57.633电视体育[4541:ef03]需要 把钥匙拿来
2011-09-26 13:11:57.663电视体育[4541:ef03] 我需要把它拿回来
2011-09-26 13:11:57.669 TVSOPERTS[4541:ef03]需要把它拿回来
2011-09-26 13:11:57.846电视体育[4541:ef03]-[UIDeviceWhiteColor channelImageFetched:：发送到实例的选择器无法识别 0x65a1e30
2011-09-26 13:11:57.847电视体育[4541:ef03]* 由于未捕获异常而终止应用程序 “NSInvalidArgumentException”，原因：“-[UIDeviceWhiteColor channelImageFetched:：发送到实例的选择器无法识别 0x65a1e30'
*第一次抛出调用堆栈：
（0x15da272 0x1769ce6 0x15dbf0d 0x1540e2f 0x1540c12 0x15dc092 0x3adf8 0x15dc092 0x24c43 0x15dc092 0xef9fac 0x15aec0f 0x15118c3 0x15111a4 0x1510b04 0x1510a1b 0x1ce6f67 0x1ce702c 0x608cf2 0x2718 0x2675 0x1）
终止调用的抛出 异常（gdb）

或者我在ASIHTTPRequest中的一行上获得了EXC_BAD_访问权限（我无法复制最后10次尝试）

谁能看出我做错了什么？Whe

[...]
    if (fileExists)
    {
        NSLog(@"Downloaded image!");
        [[self delegate] performSelector:[self didRecieveImageForChannelSelector] withObject:imagePath withObject:indexPath];
    }
    else {
        NSLog(@"Need to fetch the image!");

        NSURL *theUrl = [NSURL URLWithString:url];

        ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:theUrl];
        [request setDidFinishSelector:@selector(channelImageFetched:)];
        [request setDidFailSelector:@selector(processFailed:)];
        [request setTimeOutSeconds:60];
        [request setDownloadDestinationPath:imagePath];

        objc_setAssociatedObject(request, &kAssociationKey, indexPath, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

        [request startAsynchronous];
    }
[...]