我正在iOS 8上使用自适应布局,我希望得到viewDidLoad
上的大小类。关于那个的任何想法?
从iOS 8开始,UIViewController采用UITraitEnvironment协议。此协议声明了一个名为traitCollection的属性,该属性的类型为UITraitCollection。您可以通过使用self.traitCollection
来访问traitCollection属性
UITraitCollection有两个要访问的属性,名为horizontalSizeClass和verticalSizeClass访问这些属性会返回一个NSInteger。定义返回值的枚举在官方文档中声明如下 - (这可能会在将来添加!)
typedef NS_ENUM (NSInteger, UIUserInterfaceSizeClass {
UIUserInterfaceSizeClassUnspecified = 0,
UIUserInterfaceSizeClassCompact = 1,
UIUserInterfaceSizeClassRegular = 2,
};
所以你可以得到这个类并使用一个开关来确定你的代码方向。一个例子可能是 -
NSInteger horizontalClass = self.traitCollection.horizontalSizeClass;
NSInteger verticalCass = self.traitCollection.verticalSizeClass;
switch (horizontalClass) {
case UIUserInterfaceSizeClassCompact :
// horizontal is compact class.. do stuff...
break;
case UIUserInterfaceSizeClassRegular :
// horizontal is regular class.. do stuff...
break;
default :
// horizontal is unknown..
break;
}
// continue similarly for verticalClass etc.
Swift 4的一些有用的东西:
UIViewController扩展以将类作为元组返回。
extension UIViewController {
func sizeClass() -> (UIUserInterfaceSizeClass, UIUserInterfaceSizeClass) {
return (self.traitCollection.horizontalSizeClass, self.traitCollection.verticalSizeClass)
}
}
使用函数的示例Switch语句:
switch self.sizeClass() {
case (UIUserInterfaceSizeClass.unspecified, UIUserInterfaceSizeClass.unspecified):
print("Unknown")
case (UIUserInterfaceSizeClass.unspecified, UIUserInterfaceSizeClass.compact):
print("Unknown width, compact height")
case (UIUserInterfaceSizeClass.unspecified, UIUserInterfaceSizeClass.regular):
print("Unknown width, regular height")
case (UIUserInterfaceSizeClass.compact, UIUserInterfaceSizeClass.unspecified):
print("Compact width, unknown height")
case (UIUserInterfaceSizeClass.regular, UIUserInterfaceSizeClass.unspecified):
print("Regular width, unknown height")
case (UIUserInterfaceSizeClass.regular, UIUserInterfaceSizeClass.compact):
print("Regular width, compact height")
case (UIUserInterfaceSizeClass.compact, UIUserInterfaceSizeClass.compact):
print("Compact width, compact height")
case (UIUserInterfaceSizeClass.regular, UIUserInterfaceSizeClass.regular):
print("Regualr width, regular height")
case (UIUserInterfaceSizeClass.compact, UIUserInterfaceSizeClass.regular):
print("Compact width, regular height")
}
编辑/添加:
如果你试图在UIViewController
的生命周期早期访问特征集合,他们可能都是UIUserInterfaceSizeClass.unspecified
。
如果碰巧在代码中做约束,这可能会很痛苦。
我建议从.traitCollection
共享对象访问UIScreen
。
UIScreen.main.traitCollection
甚至更有用:
UIScreen.main.traitCollection.userInterfaceIdiom
这对测试/调试很有用:
let sizeClasses = ["Unspecified", "Compact", "Regular"]
print("SizeClass w:\(sizeClasses[traitCollection.horizontalSizeClass.rawValue]) h:\(sizeClasses[traitCollection.verticalSizeClass.rawValue])")
你也可以在Swift 5中这样做
enum DeviceTraitStatus {
///IPAD and others: Width: Regular, Height: Regular
case wRhR
///Any IPHONE Portrait Width: Compact, Height: Regular
case wChR
///IPHONE Plus/Max Landscape Width: Regular, Height: Compact
case wRhC
///IPHONE landscape Width: Compact, Height: Compact
case wChC
static var current:DeviceTraitStatus{
switch (UIScreen.main.traitCollection.horizontalSizeClass, UIScreen.main.traitCollection.verticalSizeClass){
case (UIUserInterfaceSizeClass.regular, UIUserInterfaceSizeClass.regular):
return .wRhR
case (UIUserInterfaceSizeClass.compact, UIUserInterfaceSizeClass.regular):
return .wChR
case (UIUserInterfaceSizeClass.regular, UIUserInterfaceSizeClass.compact):
return .wRhC
case (UIUserInterfaceSizeClass.compact, UIUserInterfaceSizeClass.compact):
return .wChC
default:
return .wChR
}
}
}
主要优点是不仅可以使用UIViewController类,而且静态方法可以进入Helper类。所以你可以在代码中的某个地方做:
let textSize:CGFloat = DeviceTraitStatus.current == .wRhR ? 18:14
因此,对于自动布局,您可以根据每个不同大小的类设计应用程序的UI。操作系统完成了确定所使用设备以及应使用的大小类的所有工作。但是,如果您有办法找出正在使用的设备。我不确定你是否可以决定使用什么大小的类,因为这是由OS动态处理的。
获取设备的代码:
NSString *device = [[UIDevice currentDevice]model ] ;
NSLog(@"%@",device);