在 iOS 上使用 Facebook Graph API

Question

这是我在 StackOverflow 上的第一篇文章，但我使用它很长一段时间...

我的问题基本上很简单，我想在用户墙上分享 UITextView(mShareText) 的内容，而不提示任何内容对话。基本上，用户必须在 UITextView 上填写消息，然后单击“post”UIButton。很简单不是吗？

我已经下载了 Facebook iOS SDK 并将其复制到我的项目中。我已在控制器的头文件中包含“FBConnect.h”和“Facebook.h”，并创建了一个 var ： Facebook* facebook; ，控制器还实现了以下委托：FBSessionDelegate、FBRequestDelegate。

在我的控制器的实现文件中，当用户单击“post”UIButton 时，我会触发 IBAction。

- (IBAction)onShareByFBPressed:(id)sender {
NSLog(@"onShareByFBPressed");

// Facebook settings
NSMutableDictionary* params = [[NSMutableDictionary alloc] initWithCapacity:3];

[params setObject:mShareText.text forKey:@"message"];
[params setObject:@"http://www.example.com" forKey:@"link"];
[params setObject:@"https://www.example.com/myImg.jpg" forKey:@"picture"];

[facebook requestWithGraphPath:@"me/feed" 
                         andParams:params
                     andHttpMethod:@"POST"
                       andDelegate:self];
    [params release];
}

我已经在我的 viewdidload 上实现了这个：

- (void)viewDidLoad
{
    NSLog(@"viewDidLoad");
    [super viewDidLoad];

(...)

    // Test facebook
    facebook = [[Facebook alloc] initWithAppId:@"XXXXXXXXXXX" andDelegate:self];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    if ([defaults objectForKey:@"FBAccessTokenKey"] && [defaults objectForKey:@"FBExpirationDateKey"]) {
        facebook.accessToken = [defaults objectForKey:@"FBAccessTokenKey"];
        facebook.expirationDate = [defaults objectForKey:@"FBExpirationDateKey"];
        NSLog(@"AccessToken: %@ ExpirationDate: %@", facebook.accessToken, facebook.expirationDate);
    }else{
        NSLog(@"No AccessToken or ExpirationDate");
    }
    if (![facebook isSessionValid]) {
        [facebook authorize:[NSArray arrayWithObjects:@"publish_stream", nil]];
    }
}

由于委托，我必须实现以下不同的方法：

// Pre 4.2 support
- (BOOL)application:(UIApplication *)application handleOpenURL:(NSURL *)url {
    return [facebook handleOpenURL:url]; 
}

// For 4.2+ support
- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation {
    return [facebook handleOpenURL:url]; 
}

- (void)fbDidLogin {
    NSLog(@"fbDidLogin");
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    [defaults setObject:[facebook accessToken] forKey:@"FBAccessTokenKey"];
    [defaults setObject:[facebook expirationDate] forKey:@"FBExpirationDateKey"];
    [defaults synchronize];
}

- (void)fbSessionInvalidated{
    NSLog(@"fbSessionInvalidated");
}

- (void)fbDidLogout{
    NSLog(@"fbDidLogout");
}

- (void)fbDidExtendToken:(NSString*)accessToken expiresAt:(NSDate*)expiresAt{
    NSLog(@"fbDidExtendToken");
}

- (void)fbDidNotLogin:(BOOL)cancelled{
    NSLog(@"fbDidNotLogin");
}

- (void)request:(FBRequest *)request didReceiveResponse:(NSURLResponse *)response{
    NSLog(@"didReceiveResponse: %@", response);
}

- (void)request:(FBRequest *)request didFailWithError:(NSError *)error{
    NSLog(@"didFailWithError: %@", [error description]);
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Share on Facebook" 
                                                message:@"An error occured" 
                                               delegate:nil 
                                      cancelButtonTitle:@"OK"
                                      otherButtonTitles:nil];
    [alert show];
    [alert release];
}

不幸的是，每次我尝试触发我的“onShareByFBPressed”方法时，我都会在日志中收到以下错误：

2012-02-17 13:02:06.401 Mixtapes[935:707] didFailWithError: Error Domain=facebookErrDomain     Code=10000 "The operation couldn’t be completed. (facebookErrDomain error 10000.)"     UserInfo=0x1f6f60 {error=<CFBasicHash 0x1f6660 [0x3ec6d630]>{type = mutable dict, count = 3,
entries =>
    2 : <CFString 0x1f64a0 [0x3ec6d630]>{contents = "type"} = <CFString 0x1f6b10     [0x3ec6d630]>{contents = "OAuthException"}
    3 : <CFString 0x1f6ab0 [0x3ec6d630]>{contents = "message"} = <CFString 0x1f6a10     [0x3ec6d630]>{contents = "An active access token must be used to query information about the     current user."}
    6 : <CFString 0x1f6e60 [0x3ec6d630]>{contents = "code"} = 2500
}
}

任何人都可以告诉我出了什么问题吗？与我的实施？

多谢。

此致。

编辑： @Adil

感谢您的建议。它有时确实有效。

有时我会收到以下错误：

didFailWithError: Error Domain=facebookErrDomain Code=10000 "The operation couldn’t be     completed. (facebookErrDomain error 10000.)" UserInfo=0xa17e0d0 {error=<CFBasicHash 0xa171e10     [0x3ec6d630]>{type = mutable dict, count = 3,
entries =>
    2 : <CFString 0xa179d10 [0x3ec6d630]>{contents = "type"} = <CFString 0xa17a280     [0x3ec6d630]>{contents = "OAuthException"}
    3 : <CFString 0x6127710 [0x3ec6d630]>{contents = "message"} = <CFString 0xa178db0     [0x3ec6d630]>{contents = "Error validating access token: Session is invalid. This could be     because the application was uninstalled after the session was created."}
    6 : <CFString 0xa17e020 [0x3ec6d630]>{contents = "code"} = 190
}
}

感谢您的帮助

Answer 1

这里的问题是：

被授权的facebook是AppDelegate的facebook对象，而不是你的ViewController的facebook。

解决方案：

而是为每个 ViewController 或您需要的地方分配新的 Facebook 对象。
您应该为您的应用程序创建一个属性delegate。像这样：

在 appDelegate.h 中

@property(nonatomic, retain) Facebook *facebook;

并在 appDelegate.m 中综合它，现在将 Facebook 的初始化放在

- (BOOL)application:(UIApplication *)ap didFinishLaunchingWithOptions:(NSDictionary *)op
{
// other code.... 

    facebook = [[Facebook alloc] initWithAppId:@"XXXXXXXXXXX" andDelegate:self];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    if ([defaults objectForKey:@"FBAccessTokenKey"] && [defaults objectForKey:@"FBExpirationDateKey"]) {
        facebook.accessToken = [defaults objectForKey:@"FBAccessTokenKey"];
        facebook.expirationDate = [defaults objectForKey:@"FBExpirationDateKey"];
        NSLog(@"AccessToken: %@ ExpirationDate: %@", facebook.accessToken, facebook.expirationDate);
    }else{
        NSLog(@"No AccessToken or ExpirationDate");
    }
    return true;
}

现在你想使用它的地方，编写如下内容：

- (void)viewDidLoad
{
    [super viewDidLoad];

    //...
    AppDelegate *app = (AppDelegate *)[[UIApplication sharedApplication] delegate];     
    facebook = app.facebook;    
    if (![facebook isSessionValid]) {
        [facebook authorize:[NSArray arrayWithObjects:@"publish_stream", nil]];
    }
}

Answer 2

尝试取消对您的应用程序的授权，然后再次授权