iOS-在viewDidLoad上检测当前大小类
我正在使用iOS 8上的自适应布局，我想确切地了解viewDidLoad上的大小类。对此有什么想法吗？
回答 5
Stack Overflow用户
发布于 2015-04-09 03:57:09
从UIViewController 8开始，iOS采用了UITraitEnvironment协议。此协议声明一个名为traitCollection的属性，该属性的类型为UITraitCollection.。因此，只需使用traitCollection就可以访问self.traitCollection属性。
UITraitCollection有两个要访问的属性，名为horizontalSizeClass，而访问这些属性的verticalSizeClass则返回NSInteger。定义返回值的枚举在正式文档中声明如下(这可能会在将来添加到！)
typedef NS_ENUM (NSInteger, UIUserInterfaceSizeClass {
UIUserInterfaceSizeClassUnspecified = 0,
UIUserInterfaceSizeClassCompact = 1,
UIUserInterfaceSizeClassRegular = 2,
};这样您就可以得到类并使用一个开关来确定您的代码方向。一个例子可以是-
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.Stack Overflow用户
发布于 2017-04-10 17:26:40
Swift 4的一些有用的东西：
UIViewController扩展，使类返回为元组。
extension UIViewController {
func sizeClass() -> (UIUserInterfaceSizeClass, UIUserInterfaceSizeClass) {
return (self.traitCollection.horizontalSizeClass, self.traitCollection.verticalSizeClass)
}
}示例Switch语句来使用该函数：
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：
如果您试图在UIViewController生命周期的早期访问特性集合，那么它们都可能是UIUserInterfaceSizeClass.unspecified。
如果您碰巧在代码中执行约束，这可能会很痛苦。
我建议从.traitCollection共享对象访问UIScreen。
UIScreen.main.traitCollection或者更有用：
UIScreen.main.traitCollection.userInterfaceIdiomStack Overflow用户
发布于 2018-10-26 10:38:03
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
}
}
}主要的优点是不仅可以从UIViewController类依赖者中使用，而且静态方法可以进入一个即帮助类。因此，您可以在代码中的某个位置执行以下操作：
let textSize:CGFloat = DeviceTraitStatus.current == .wRhR ? 18:14https://stackoverflow.com/questions/29528661
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