00. Call the Macro definition of Objective-C in Swift

(Updated: )
Swift › 08. Hybrid Programming
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It will take about 3 minutes to finish reading this article.

There are usually lots of macro definitions in Objective-C projects, as follows:

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#define kScreenScale [UIScreen mainScreen].scale
#define kOnePixelPointValue (1.0f / kScreenScale)
#define kScreenWidth  [[UIScreen mainScreen] bounds].size.width
#define kScreenHeight [[UIScreen mainScreen] bounds].size.height
#define kApplicationWidth  MIN([[UIScreen mainScreen] bounds].size.width, [[UIScreen mainScreen] bounds].size.height)
#define kApplicationHeight MAX([[UIScreen mainScreen] bounds].size.width, [[UIScreen mainScreen] bounds].size.height)
#define kScreenCenterX kScreenWidth / 2.0
#define kScreenCenterY kScreenHeight / 2.0

Actually, Swift cannot directly use the macro definitions of OC. We need to do some conversions For Swift.

1. Overwrite them with Swift language entirely

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public struct SizeDefault {
    public static let screenScale = UIScreen.main.scale
    public static let onePixelPointValue = (1.0 / screenScale)
    public static let screenWidth = UIScreen.main.bounds.size.width
    public static let screenHeight = UIScreen.main.bounds.size.height
    public static let applicationWidth = min(screenWidth, screenHeight)
    public static let applicationHeight = max(screenWidth, screenHeight)
    public static let screenCenterX = screenWidth / 2.0
    public static let screenCenterY = screenHeight / 2.0
    ...
}
extension UIDevice {
    public static let ako = SizeDefault.self
}

I overwrited all the code and wrapped them in the UIDevice extension, then I can use them as follows:

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let height = UIDevice.ako.applicationHeight
print(height)

This is what I recommend if you have enough time.

2. Convert them with inline function simply

In fact, there are some macros that comprise complicated logic code and you don not have enough time or confidence to overwrite them. Therefore, there is a compromise method to meet our requirement quickly and safely.

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#define isIPhoneXSeries ({  \
    BOOL iPhoneXSeries = NO;  \
    if ([UIDevice currentDevice].userInterfaceIdiom != UIUserInterfaceIdiomPhone) { \
        return iPhoneXSeries; \
    } \
    if (@available(iOS 11.0, *)) { \
        UIWindow *mainWindow = [[[UIApplication sharedApplication] delegate] window]; \
        if (mainWindow.safeAreaInsets.bottom > 0.0) { \
            iPhoneXSeries = YES; \
        } \
    } \
    iPhoneXSeries; \
})

We can just convert it with incline function like that:

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static inline BOOL isIPhoneXSeries()
{
    BOOL iPhoneXSeries = NO;
    if ([UIDevice currentDevice].userInterfaceIdiom != UIUserInterfaceIdiomPhone) {
        return iPhoneXSeries;
    }
    if (@available(iOS 11.0, *)) {
        UIWindow *mainWindow = [[[UIApplication sharedApplication] delegate] window];
        if (mainWindow.safeAreaInsets.bottom > 0.0) {
            iPhoneXSeries = YES;
        }
    }
    return iPhoneXSeries;
}

or like this:

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static inline CGFloat AKOApplicationWidth()
{
    return kApplicationWidth;
}

static inline CGFloat AKOApplicationHeight()
{
    return kApplicationHeight;
}

It is very convenient. And then We can use it in our Project like this:

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isIPhoneXSeries()

We can also add it to UIDevice extension like as below:

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public struct SizeDefault {
  ...
  public static let isIPhoneXSeries = AKOISIPhoneXSeries()
  ...