iphone - 使用 FBGraph 登录 Facebook

Question

我是 iOS 开发的新手。我想从我的 iPhone 应用程序连接到 Facebook。我按照FBGraph API来了解我们如何在我们的应用程序中使用 Facebook，例如：

打印登录用户的信息：

FbGraphResponse *fb_graph_response = [fbGraph doGraphGet:@"me" withGetVars:nil];
NSLog(@"getMeButtonPressed:  %@", fb_graph_response.htmlResponse);

或好友列表：

FbGraphResponse *fb_graph_response = [fbGraph doGraphGet:@"me/friends" withGetVars:nil];
NSLog(@"getMeFriendsButtonPressed:  %@", fb_graph_response.htmlResponse);

这是doGraphGet方法FbGraph.m：

- (FbGraphResponse *)doGraphGet:(NSString *)action withGetVars:(NSDictionary *)get_vars {

    NSString *url_string = [NSString stringWithFormat:@"https://graph.facebook.com/%@?", action];

    //tack on any get vars we have...
    if ( (get_vars != nil) && ([get_vars count] > 0) ) {

        NSEnumerator *enumerator = [get_vars keyEnumerator];
        NSString *key;
        NSString *value;
        while ((key = (NSString *)[enumerator nextObject])) {

            value = (NSString *)[get_vars objectForKey:key];
            url_string = [NSString stringWithFormat:@"%@%@=%@&", url_string, key, value];

        }//end while    
    }//end if

    if (accessToken != nil) {
        //now that any variables have been appended, let's attach the access token....
        url_string = [NSString stringWithFormat:@"%@access_token=%@", url_string, self.accessToken];
    }

首先我们需要登录到 Facebook，如下所示：

我猜它在 FbGraph.m 中使用了这段代码（使用UIWebView）：

self.redirectUri = @"http://www.facebook.com/connect/login_success.html";

- (void)authenticateUserWithCallbackObject:(id)anObject andSelector:(SEL)selector andExtendedPermissions:(NSString *)extended_permissions andSuperView:(UIView *)super_view {

    self.callbackObject = anObject;
    self.callbackSelector = selector;

    NSString *url_string = [NSString stringWithFormat:@"https://graph.facebook.com/oauth/authorize?client_id=%@&redirect_uri=%@&scope=%@&type=user_agent&display=touch", facebookClientID, redirectUri, extended_permissions];
    NSURL *url = [NSURL URLWithString:url_string];
    NSURLRequest *request = [NSURLRequest requestWithURL:url];

    CGRect webFrame = [super_view frame];

    webFrame.origin.y = 0;
    UIWebView *aWebView = [[UIWebView alloc] initWithFrame:webFrame];
    [aWebView setDelegate:self];    
    self.webView = aWebView;

    [aWebView release];

    [webView loadRequest:request];  
    [super_view addSubview:webView];
}

我的问题是关于一种可能性。我可以自己有一个机制从用户那里获取电子邮件和密码然后登录（就像其他方法一样，例如在控制台中打印身份验证失败或成功登录）？

Answer 1

On click of button and its event is say fbLogin then add this code for login

-(void)fbLogin
{
   if(!self.fbGraph.accesstoken) // doesnot have access token. So needed to login
   {
    NSString *client_id = @"130902823636657"; //get your own client id from facebook

    //alloc and initalize our FbGraph instance
    self.fbGraph = [[FbGraph alloc] initWithFbClientID:client_id];

    //begin the authentication process.....
    [self.fbGraph authenticateUserWithCallbackObject:self andSelector:@selector(fbGraphCallback:) andExtendedPermissions:@"user_photos,user_videos,publish_stream,offline_access,user_checkins,friends_checkins"];
   }
   else
   {
      // Add UIAlert as user is logged in already
      //pop a message letting them know most of the info will be dumped in the log
      UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Note" message:@"user is logged in already" delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
      [alert show];
      [alert release];
   }
}

Now when user is authebticated this method below is called. So add this method in your .h file.

#pragma mark -
#pragma mark FbGraph Callback Function
/**
* This function is called by FbGraph after it's finished the authentication process
**/
- (void)fbGraphCallback:(id)sender 
{

 if ( (self.fbGraph.accessToken == nil) || ([self.fbGraph.accessToken length] == 0) ) 
 {

  UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Note" message:@"Try Again" delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
  [alert show];
  [alert release];

  //restart the authentication process.....
  //[self.fbGraph authenticateUserWithCallbackObject:self andSelector:@selector(fbGraphCallback:) andExtendedPermissions:@"user_photos,user_videos,publish_stream,offline_access,user_checkins,friends_checkins"];

 } 
 else 
 {
  //pop a message letting them know most of the info will be dumped in the log
  UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Note" message:@"Logged In Successfully" delegate:nil cancelButtonTitle:@"Ok" otherButtonTitles:nil];
  [alert show];
  [alert release];
  NSLog(@"------------>CONGRATULATIONS<------------, You're logged into Facebook... Your oAuth token is: %@", self.fbGraph.accessToken);
 }
}