调用contentsOfUrl构造函数时，NSData返回nil

Question

let myProfilePictureURL = NSURL(string: "http://graph.facebook.com/bobdylan/picture")
let imageData           = NSData(contentsOfURL: myProfilePictureURL!)

In the above code, imageData is nil after execution. Any idea, what could be wrong here?

Answer 1

The issue is actually you don't have any data in that specified url. If you paste that on the browser, it redirects to some other url and loads the image/data. That's why you are getting nil there.

Answer 2

Facebook always provides a absolute URL to your profile image. You can paste that url in any browser and will display that image. Please check the image url that you are getting from Facebook.

Answer 3

You're not getting data because you're not trying to laod the image but the "page". Using your link, I can see the image, and considering what's in the url i suggest you replace

let myProfilePictureURL = NSURL(string:"http://graph.facebook.com/bobdylan/picture")

with this

let myProfilePictureURL = NSURL(string:"https://fbcdn-profile-a.akamaihd.net/hprofile-ak-xpa1/v/t1.0-1/p50x50/63781_10154869387235696_5558117780840742364_n.jpg?oh=92218e0caca2cbaa28266ef30757d4e2&oe=55780E74&__gda__=1434574503_cdb40e50a7c5770845fbbb6098bf073a")

I got this URL by either copying what's in the browser navigation bar (on the top of the screen) or simply by right cliking and then clicking " Copy URL of Image ".