問題描述
如何在打開 Facebook 登錄對話框之前告訴 iPhone 應用用戶會發生什麼 (How to tell an iphone app user what will happen before opening Facebook login dialogue)
Apps that allow users to log in over a 3rd party authentication provider (e.g. Facebook, Google, Twoitter,...) should open a browser window to let the user authenticate against the provider. That means, at some point, an app is backgrounded and the user interacts with a browser window. Just before the browser opens, it's a recommended pratctice to inform the user about what will happen (see e.g. Getting Started with OAuth 2.0 ‑ O'Reilly), let's say an alert window with something like "you will leave now the XYZ app and a browser window will open where you can enter your credentials safely".
My question: How can that be done if I use the facebook SDK for ios? Looking at the SDK, there seem to be no notifications and no designated states that would allow me to detect that the sdk is about to background my app and about to opening either Safari or the Facebook app.
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參考解法
方法 1:
Use a simple alert that explains what will happen when pressing the button (or however you choose to do it). And when the user has pressed the OK on the alert sign them in.
However I'm quite certain that in Facebook terms of service you have to have some sort of Facebook trademark before interacting with facebook and it seems like standard practice to mention facebook in some way on a button and then log‑in the user without mentioning it, since it plays on the user expectation.
Especially when using iOS 6.0 and Facebook SDK 3.1 for iOS, then Facebooks SDK takes care of most of that in it's own.
(by docno、Joakim Engstrom)