使用 FBGraph 登录 Facebook

我是 iOS 开发新手。我想从我的 iPhone 应用程序连接到 Facebook。我跟着FBGraph API https://github.com/reallylongaddress/iPhone-Facebook-Graph-API/tree/59e639922c4bf6953162ea81998f2ff951cd1769看看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中的方法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 Facebook，如图所示：

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。我是否可以拥有一种自己的机制来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）？

单击按钮及其事件是 fbLogin 然后添加此代码进行登录

-(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];
   }
}

现在，当用户通过身份验证时，将调用下面的方法。因此，请将此方法添加到您的 .h 文件中。

#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);
 }
}