Detecting the device upside down

Question

what are the correct values for detecting the device upside down?

I have the following and it starts detecting when the user has titled the device on its back.

I use the following values

float xx = -[acceleration x];
    float yy = [acceleration y];
    float angle = atan2(yy, xx);

    if(angle >= 0.75 && angle <= 2.25)
    {
        NSLog(@"Upside down");
    }

Don't try to reinvent the wheel here. This is documented in the UIDevice API. — W Dyson, Sep 29 '11 at 00:45

score 7 · Accepted Answer · answered Sep 29 '11 at 00:48

7

Start listening for orientation events by using:

UIDevice *currDevice = [UIDevice currentDevice];
[currDevice beginGeneratingDeviceOrientationNotifications];

Then, get the orientation using:

currDevice.orientation

These are the values that are returned:

{'1' : 'Portrait', '2' : 'PortraitUpsideDown', '3' : 'LandscapeLeft', '4' : 'LandscapeRight', '5' : 'FaceUp', '6' : 'FaceDown'}

answered Sep 29 '11 at 00:48

JCox

86
2

so in your case, you'd want to listen for when currDevice.orientation is 6 – JCox Sep 29 '11 at 00:48
I had to get the orientation == 2. Thanks, this helped me solve it. – user773578 Sep 29 '11 at 11:47

score 1 · Answer 2 · answered Sep 29 '11 at 00:40

1

UIDevice Class Reference

See 'Getting the Device Orientation' part.

answered Sep 29 '11 at 00:40

ChangUZ

5,380
10
46
64

score 0 · Answer 3 · answered Sep 29 '11 at 03:07

0

this is my approach (with code) to implement device orientations handling on iOS, and you can use it if you like:

How to handle UIDeviceOrientation for manage views layouts

answered Sep 29 '11 at 03:07

Detecting the device upside down

3 Answers3