GoldenJoe GoldenJoe - 4 years ago 161
iOS Question

Detecting iOS orientation change instantly

I have a game in which the orientation of the device affects the state of the game. The user must quickly switch between Landscape, Portrait, and Reverse Landscape orientations. So far I've been registering the game for orientation notifications via:

[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];

But it is far too slow - there seems to be about a second delay between rotating the phone and the notification actually being fired. I need a way to INSTANTLY detect changes in the device's orientation. I have tried experimenting with the gyroscope, but am not yet familiar enough with it to know whether or not it is the solution I am looking for.

Answer Source

That delay you're talking about is actually a filter to prevent false (unwanted) orientation change notifications.

For instant recognition of device orientation change you're just gonna have to monitor the accelerometer yourself.

Accelerometer measures acceleration (gravity included) in all 3 axes so you shouldn't have any problems in figuring out the actual orientation.

Some code to start working with accelerometer can be found here:

How to make an iPhone App – Part 5: The Accelerometer

And this nice blog covers the math part:

Using the Accelerometer

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