功能用法:
1.常规:
enum PrinterType : String , CaseIterable {
case receipt = "Receipt"
case kitchen = "Kitchen"
case bar = "Bar"
case packing = "Packing"
case label = "Label"
}
print(PrinterType.allCases)
//------------------
PrinterType.receipt
PrinterType.kitchen
PrinterType.bar
PrinterType.packing
PrinterType.label
//------------------
2.如果枚举中某一元素不想被列出来,我们这就需要自定义了
enum PrinterType : String , CaseIterable {
static var allCases:[PrinterType]{
return [.receipt,.kitchen, .bar, .packing]
}
case receipt = "Receipt"
case kitchen = "Kitchen"
case bar = "Bar"
case packing = "Packing"
case label = "Label"
}
print(PrinterType.allCases)
//------------------
PrinterType.receipt
PrinterType.kitchen
PrinterType.bar
PrinterType.packing
//------------------
这个时候我们写不写,遵不遵守CaseIterable这个协议都无所谓了,因为没有这个协议的时候我们就是这么写来拿到枚举中的各个元素的。