iOS判断设备圆角（SafeArea）

遇见的问题

随着2018年秋季发布会的新款iPhone以及iPad的发布，我们适配圆角的场景越来越多，曾经只需要针对iPhone X的适配，而现在要面对的圆角机型已经包含四款iPhone和两款iPad以及iWatch。判断是否有圆角，一种是判断机型，另一种是通过window的safeAreaInsets.bottom来判断。

不同方案

• 方案一

  通过获取具体机型来判断

// 需要#import 
- (NSString*)deviceModelName
{
    struct utsname systemInfo;
    uname(&systemInfo);
    NSString *deviceModel = [NSString stringWithCString:systemInfo.machine encoding:NSUTF8StringEncoding];
    
    if ([deviceModel isEqualToString:@"iPhone3,1"])    return @"iPhone 4";
    if ([deviceModel isEqualToString:@"iPhone3,2"])    return @"iPhone 4";
    if ([deviceModel isEqualToString:@"iPhone3,3"])    return @"iPhone 4";
    if ([deviceModel isEqualToString:@"iPhone4,1"])    return @"iPhone 4S";
    if ([deviceModel isEqualToString:@"iPhone5,1"])    return @"iPhone 5";
    if ([deviceModel isEqualToString:@"iPhone5,2"])    return @"iPhone 5 (GSM+CDMA)";
    if ([deviceModel isEqualToString:@"iPhone5,3"])    return @"iPhone 5c (GSM)";
    if ([deviceModel isEqualToString:@"iPhone5,4"])    return @"iPhone 5c (GSM+CDMA)";
    if ([deviceModel isEqualToString:@"iPhone6,1"])    return @"iPhone 5s (GSM)";
    if ([deviceModel isEqualToString:@"iPhone6,2"])    return @"iPhone 5s (GSM+CDMA)";
    if ([deviceModel isEqualToString:@"iPhone7,1"])    return @"iPhone 6 Plus";
    if ([deviceModel isEqualToString:@"iPhone7,2"])    return @"iPhone 6";
    if ([deviceModel isEqualToString:@"iPhone8,1"])    return @"iPhone 6s";
    if ([deviceModel isEqualToString:@"iPhone8,2"])    return @"iPhone 6s Plus";
    if ([deviceModel isEqualToString:@"iPhone8,4"])    return @"iPhone SE";
    // 日行两款手机型号均为日本独占，可能使用索尼FeliCa支付方案而不是苹果支付
    if ([deviceModel isEqualToString:@"iPhone9,1"])    return @"国行、日版、港行iPhone 7";
    if ([deviceModel isEqualToString:@"iPhone9,2"])    return @"港行、国行iPhone 7 Plus";
    if ([deviceModel isEqualToString:@"iPhone9,3"])    return @"美版、台版iPhone 7";
    if ([deviceModel isEqualToString:@"iPhone9,4"])    return @"美版、台版iPhone 7 Plus";
    if ([deviceModel isEqualToString:@"iPhone10,1"])   return @"iPhone_8";
    if ([deviceModel isEqualToString:@"iPhone10,4"])   return @"iPhone_8";
    if ([deviceModel isEqualToString:@"iPhone10,2"])   return @"iPhone_8_Plus";
    if ([deviceModel isEqualToString:@"iPhone10,5"])   return @"iPhone_8_Plus";
    if ([deviceModel isEqualToString:@"iPhone10,3"])   return @"iPhone_X";
    if ([deviceModel isEqualToString:@"iPhone10,6"])   return @"iPhone_X";
    if ([deviceModel isEqualToString:@"iPhone11,2"])   return @"iPhone XS";
    if ([deviceModel isEqualToString:@"iPhone11,4"])   return @"iPhone XS Max";
    if ([deviceModel isEqualToString:@"iPhone11,6"])   return @"iPhone XS Max";
    if ([deviceModel isEqualToString:@"iPhone11,8"])   return @"iPhone XR";
    
    if ([deviceModel isEqualToString:@"iPod1,1"])      return @"iPod Touch 1G";
    if ([deviceModel isEqualToString:@"iPod2,1"])      return @"iPod Touch 2G";
    if ([deviceModel isEqualToString:@"iPod3,1"])      return @"iPod Touch 3G";
    if ([deviceModel isEqualToString:@"iPod4,1"])      return @"iPod Touch 4G";
    if ([deviceModel isEqualToString:@"iPod5,1"])      return @"iPod Touch (5 Gen)";
    
    if ([deviceModel isEqualToString:@"iPad1,1"])      return @"iPad";
    if ([deviceModel isEqualToString:@"iPad1,2"])      return @"iPad 3G";
    if ([deviceModel isEqualToString:@"iPad2,1"])      return @"iPad 2 (WiFi)";
    if ([deviceModel isEqualToString:@"iPad2,2"])      return @"iPad 2";
    if ([deviceModel isEqualToString:@"iPad2,3"])      return @"iPad 2 (CDMA)";
    if ([deviceModel isEqualToString:@"iPad2,4"])      return @"iPad 2";
    if ([deviceModel isEqualToString:@"iPad2,5"])      return @"iPad Mini (WiFi)";
    if ([deviceModel isEqualToString:@"iPad2,6"])      return @"iPad Mini";
    if ([deviceModel isEqualToString:@"iPad2,7"])      return @"iPad Mini (GSM+CDMA)";
    if ([deviceModel isEqualToString:@"iPad3,1"])      return @"iPad 3 (WiFi)";
    if ([deviceModel isEqualToString:@"iPad3,2"])      return @"iPad 3 (GSM+CDMA)";
    if ([deviceModel isEqualToString:@"iPad3,3"])      return @"iPad 3";
    if ([deviceModel isEqualToString:@"iPad3,4"])      return @"iPad 4 (WiFi)";
    if ([deviceModel isEqualToString:@"iPad3,5"])      return @"iPad 4";
    if ([deviceModel isEqualToString:@"iPad3,6"])      return @"iPad 4 (GSM+CDMA)";
    if ([deviceModel isEqualToString:@"iPad4,1"])      return @"iPad Air (WiFi)";
    if ([deviceModel isEqualToString:@"iPad4,2"])      return @"iPad Air (Cellular)";
    if ([deviceModel isEqualToString:@"iPad4,4"])      return @"iPad Mini 2 (WiFi)";
    if ([deviceModel isEqualToString:@"iPad4,5"])      return @"iPad Mini 2 (Cellular)";
    if ([deviceModel isEqualToString:@"iPad4,6"])      return @"iPad Mini 2";
    if ([deviceModel isEqualToString:@"iPad4,7"])      return @"iPad Mini 3";
    if ([deviceModel isEqualToString:@"iPad4,8"])      return @"iPad Mini 3";
    if ([deviceModel isEqualToString:@"iPad4,9"])      return @"iPad Mini 3";
    if ([deviceModel isEqualToString:@"iPad5,1"])      return @"iPad Mini 4 (WiFi)";
    if ([deviceModel isEqualToString:@"iPad5,2"])      return @"iPad Mini 4 (LTE)";
    if ([deviceModel isEqualToString:@"iPad5,3"])      return @"iPad Air 2";
    if ([deviceModel isEqualToString:@"iPad5,4"])      return @"iPad Air 2";
    if ([deviceModel isEqualToString:@"iPad6,3"])      return @"iPad Pro 9.7";
    if ([deviceModel isEqualToString:@"iPad6,4"])      return @"iPad Pro 9.7";
    if ([deviceModel isEqualToString:@"iPad6,7"])      return @"iPad Pro 12.9";
    if ([deviceModel isEqualToString:@"iPad6,8"])      return @"iPad Pro 12.9";
    if ([deviceModel isEqualToString:@"iPad7,1"])     return @"iPad Pro 12.9 inch 2nd gen (WiFi)";
    if ([deviceModel isEqualToString:@"iPad7,2"])     return @"iPad Pro 12.9 inch 2nd gen (Cellular)";
    if ([deviceModel isEqualToString:@"iPad7,3"])     return @"iPad Pro 10.5 inch (WiFi)";
    if ([deviceModel isEqualToString:@"iPad7,4"])     return @"iPad Pro 10.5 inch (Cellular)";
    
    if ([deviceModel isEqualToString:@"AppleTV2,1"])      return @"Apple TV 2";
    if ([deviceModel isEqualToString:@"AppleTV3,1"])      return @"Apple TV 3";
    if ([deviceModel isEqualToString:@"AppleTV3,2"])      return @"Apple TV 3";
    if ([deviceModel isEqualToString:@"AppleTV5,3"])      return @"Apple TV 4";
    
    if ([deviceModel isEqualToString:@"i386"])         return @"Simulator";
    if ([deviceModel isEqualToString:@"x86_64"])       return @"Simulator";
    
    return deviceModel;
}

• 方案二

通过获取window的safeAreaInsets.bottom来判断是否有SafeArea。

获取window的方法很多，但是通过UIApplication的一系列方法获取的window可能为nil或者因为尺寸不是全屏大小导致safeAreaInsets.bottom的值为0，所以我选择自己创建一个window来判断。但是还是有特殊情况，即UIApplication未初始化时是无法获取到正确safeAreaInsets.bottom的值的,这种情况下，可以通过设备型号去判断，我这里直接返回了NO。

ps：这种情况在+load方法里调用这个判断会出现，一但UIApplication实例化后就能正确判断，所以这个方法能满足99%的判断场景。

• 比较
  方案一比较准确，但是需要随着新机型的出现需要维护机型列表；
  方案二在极端情况下不适用，正常声明周期中使用无问题，且在新机型发布时不需要做额外适配。
  如果不仅仅需要判断是否有圆角，还需要获取屏幕相对安全区域的高度，那么方案一就不适用了，可以通过方案二的思路来获取。

代码

方法二的实现在AZCategory项目中

或者直接使用下面的宏

#define AZ_HAS_SAFEAREA ({\
    static dispatch_once_t onceToken;\
    static BOOL hasSafeArea = NO;\
    if (![UIApplication sharedApplication].windows) {\
        (NO);\
    }else {\
        dispatch_once(&onceToken, ^{\
            if (@available(iOS 11.0, *)) {\
                UIWindow *window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];\
                hasSafeArea = window.safeAreaInsets.bottom > 0;\
            }\
        });\
    }\
    (hasSafeArea);\
})