[ricardobeat]

The latch is only obvious in retrospect; it involves the emulation of physical constraints that most non-engineers couldn't even describe succesfully (springy handle, locking at the end) and great resilience to unintended input.

If another manufacturer had made the iPhone, you would probably unlock it by pressing a sequence of keys. That's the most obvious design.

[rustynails]

I respectfully disagree. My thought process was 1. Passcode (alpha or numeric) 2. If I don't want a passcode, I need something else, and a single button won't do. Ok, drag something.

The conclusion is obvious. You could argue that I am biased, and it would be impossible for me to counter. However, IMHO, sliding something was the obvious answer.

[ricardobeat]

"drag something" was not a common interaction at the time, especially because there weren't any other products with touchscreens accurate enough for it (try to unlock a chinese %pad knockoff. they are 10x better than what existed in 2007). Remember, actually touching the screen was novelty.

[taligent]

Except that a single button WILL do. Because you still need to press it in order to wake the screen up on pretty much every phone on the market today.

Which begs the question why you wouldn't either go straight to the home screen or show a single continue button. Slide to unlock is not what most people would do in that situation.

[Blara]

I agree the latch is not a good comparison, but I did have "slide" to unlock on my walkman back in the day. (lock/unlock buttons)