自定义委托不工作
自定义委托不工作
提问于 2011-08-26 13:05:35
正如我提出的另一个问题所建议的那样，我已开始更多地与代表合作。现在，我制作了一个名为UIViewController的ProfileViewController，我想在其中加载Facebook上的新闻提要。我还有一个名为NSObject的子类FBFeed。这个子类加载Facebook并将其传递回视图控制器。我对Facebook的所有请求都是通过一个名为FBRequestWrapper的单例发送的，它(在本例中)应该将结果传递给FBFeed。
我在getFBRequestWithGraphPath:andDelegate:中调用FBRequestWrapper，它将调用Facebook iOS SDK中的一个方法，该方法接受委托作为参数。如果我输入了self (这将是FBRequestWrapper)，它就会工作得很好。如果我输入_delegate (这是FBFeed的一个实例)，应用程序就会与EXC_BAD_ACCESS崩溃。
我有个解释它会崩溃的原因。我读过
@property (nonatomic, retain) id <FBFeedDelegate> delegate;应该是
@property (nonatomic, assign) id <FBFeedDelegate> delegate;但是，当这样做时，我会得到以下错误：
现有的unsafe_unretained属性‘委托’的ivar‘委托’必须是__unsafe_unretained
而且，我不知道这是否足以使应用程序崩溃。
这是我的密码。
ProfileViewController.h
#import <UIKit/UIKit.h>
#import "FeedTableView.h"
#import "FBFeed.h"
@interface ProfileViewController : UIViewController <FBFeedDelegate>
{
FeedTableView *tableView;
}
- (void)loadFeed;
@endProfileViewController.m
@implementation ProfileViewController
- (void)loadFeed
{
FBFeed *feed = [[FBFeed alloc] init];
[feed loadNewsFeedWithDelegate:self];
}
#pragma mark -
#pragma FBFeedDelegate
- (void)finishedLoadingFeed:(FBFeed *)_feed
{
NSLog(@"ProfileViewController: FBFeed Finished.");
}
- (void)failedToLoadFeed:(FBFeed *)_feed
{
NSLog(@"ProfileViewController: FBFeed Failed.");
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Load feed
[self loadFeed];
}
@endFBFeed.h
#import <Foundation/Foundation.h>
#import "FBRequestWrapper.h"
@protocol FBFeedDelegate;
@interface FBFeed : NSObject <FBRequestDelegate>
{
id <FBFeedDelegate> delegate;
}
@property (nonatomic, retain) id <FBFeedDelegate> delegate;
- (void)loadNewsFeedWithDelegate:(id)_delegate;
@end
@protocol FBFeedDelegate <NSObject>
@required
- (void)finishedLoadingFeed:(FBFeed *)_feed;
- (void)failedToLoadFeed:(FBFeed *)_feed;
@endFBFeed.m
#import "FBFeed.h"
@implementation FBFeed
@synthesize delegate;
- (void)loadNewsFeedWithDelegate:(id)_delegate
{
self.delegate = _delegate;
[[FBRequestWrapper defaultManager] getFBRequestWithGraphPath:@"me" andDelegate:self];
}
#pragma mark -
#pragma mark FBRequest Delegate
- (void)request:(FBRequest *)request didLoad:(id)result
{
NSLog(@"FBFeed: FBRequest Did Load.");
NSLog(@"%@", result);
}
- (void)request:(FBRequest *)request didFailWithError:(NSError *)error
{
NSLog(@"FBFeed: FBRequest Failed.");
NSLog(@"%@", error);
}
@endFBRequestWrapper.h
#import <Foundation/Foundation.h>
#import "FBConnect.h"
@interface FBRequestWrapper : NSObject <FBRequestDelegate, FBSessionDelegate>
{
Facebook *facebook;
BOOL isLoggedIn;
}
@property (nonatomic, assign) BOOL isLoggedIn;
+ (id)defaultManager;
- (void)setIsLoggedIn:(BOOL)_loggedIn;
- (void)FBSessionBegin:(id<FBSessionDelegate>)_delegate;
- (void)FBLogout;
- (void)getFBRequestWithGraphPath:(NSString *)_path andDelegate:(id)_delegate;
- (void)getFBRequestWithMethodName:(NSString *)_methodName andParams:(NSMutableDictionary *)_params andDelegate:(id)_delegate;
@endFBRequestWrapper.m
#import "FBRequestWrapper.h"
static FBRequestWrapper *defaultWrapper = nil;
@implementation FBRequestWrapper
@synthesize isLoggedIn;
+ (id)defaultManager
{
if(!defaultWrapper)
{
defaultWrapper = [[FBRequestWrapper alloc] init];
}
return defaultWrapper;
}
- (void)getFBRequestWithGraphPath:(NSString *)_path andDelegate:(id)_delegate
{
if (_path != nil)
{
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
if (_delegate == nil)
{
_delegate = self;
}
[facebook requestWithGraphPath:_path andDelegate:_delegate];
}
}
#pragma mark -
#pragma mark FBRequestDelegate
- (void)request:(FBRequest *)request didLoad:(id)result
{
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
NSLog(@"%@", result);
}
- (void)request:(FBRequest *)request didFailWithError:(NSError *)error
{
[[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
NSLog(@"FBRequest Failed: %@", error);
}
@endStack Overflow用户
发布于 2012-01-04 14:15:56
我认为你有两种方法：
- 不使用ARC并保留代码，因为如果您想使用
- ，请注意，通常不应该保留委托。但是当使用ARC时，一个像这样的ivar声明：
id <FBFeedDelegate> delegate
默认为
id <FBFeedDelegate> __strong delegate所以当你声明这样的财产时：
@property (readwrite, unsafe_unretained) id <FBFeedDelegate> delegate象牙应该是这样的：
id <FBFeedDelegate> __unsafe_unretained delegate页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/7205064
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