检查当前方向是否受支持

Question

In my property list file, I have mentioned all the supported orientations. I have many applications which support different orientations. In order to handle all the UI related stuff with all these applications, I have a common project. So, I cannot do any app specific stuff in this common project as it would affect other apps too. In one of files in this common project, I need to check if the device orientation is supported or not.

I have retrieved the supported orientations in an array using

NSArray *supportedOrientations = [[[NSBundle mainBundle] infoDictionary]     objectForKey:@"UISupportedInterfaceOrientations"]; 

my method has signature

-(BOOL) isInvalidOrientation: (UIDeviceOrientation) orientation 

I need to check if current orientation is supported or not, ie I nee to check if current orientation is there in supportedOrientations array or not.

I am unable to do that because when I use

[supportedOrientations containsObject:self.currentOrientation];

I get an error saying Implicit conversion of UIDeviceOrientation to id is disallowed with ARC.

It is because they are incompatible types. How do I check it ?

Answer 1

The problem is that the UISupportedInterfaceOrientations info key gives you an array of strings. While self.currentOrientation gives you an enum value from UIDeviceOrientation . You need a way to map the enum values to the string values. Also note that you are dealing with device orientations and interface orientations.

- (NSString *)deviceOrientationString:(UIDeviceOrientation)orientation {
    switch (orientation) (
        case UIDeviceOrientationPortrait:
            return @"UIInterfaceOrientationPortrait";
        case UIDeviceOrientationPortraitUpsideDown:
            return @"UIInterfaceOrientationPortraitUpsideDown";
        case UIDeviceOrientationLandscapeLeft:
            return @"UIInterfaceOrientationLandscapeLeft";
        case UIDeviceOrientationLandscapeRight:
            return @"UIInterfaceOrientationLandscapeRight";
        default:
            return @"Invalid Interface Orientation";
    }
}

NSString *name = [self deviceOrientationString:self.currentOrientation];

BOOL res = [supportedOrientations containsObject:name];

Answer 2

I have a similar need to determine the app supported orientations in order to pre cache some resources. But I only need to know if the app supports portrait, landscape or both. This thread led me to the following solution so I thought I might post it.

// get supported screen orientations
NSArray *supportedOrientations = [[[NSBundle mainBundle] infoDictionary]
                                  objectForKey:@"UISupportedInterfaceOrientations"];
NSString *supportedOrientationsStr = [supportedOrientations componentsJoinedByString:@" "];
NSRange range = [supportedOrientationsStr rangeOfString:@"Portrait"];
if ( range.location != NSNotFound )
{
    NSLog(@"supports portrait");
}
range = [supportedOrientationsStr rangeOfString:@"Landscape"];
if ( range.location != NSNotFound )
{
    NSLog(@"supports landscape");
}