Swift 枚舉

Swift枚舉也被稱為Swift Enum。愛掏網(wǎng) - it200.com它是由一組相關(guān)的值組成的數(shù)據(jù)類型。愛掏網(wǎng) - it200.com它在類中聲明，并且可以通過該類的實例成員訪問其值。愛掏網(wǎng) - it200.com

語法

enum enum_name
{
// values are described here
}

示例

讓我們舉一個示例來更好地理解。愛掏網(wǎng) - it200.com在這里，我們將使用一個名為“連接狀態(tài)”的枚舉，使用switch語句來查看可能的條件。愛掏網(wǎng) - it200.com

enum ConnectionStatus
{
    case Unknown
    case Disconnected
    case Connecting
    case Connected

}
var connectionStatus = ConnectionStatus.Connecting
connectionStatus = .Connected

switch connectionStatus {

    case .Disconnected:
    print("Disconnected")

    case .Connecting:
    print("Connecting")

    case .Connected:
    print("Connected")

    default:
    print("Unknown Status")
}

輸出：

Connected 

在上面的示例中，有4種情況：未知、斷開連接、連接中和已連接。愛掏網(wǎng) - it200.com輸出顯示為”Connected”，因為它被設置為已連接。愛掏網(wǎng) - it200.com如果將其設置為”Disconnected”，輸出將顯示為”Disconnected”。愛掏網(wǎng) - it200.com

enum ConnectionStatus
{
    case Unknown
    case Disconnected
    case Connecting
    case Connected

}
var connectionStatus = ConnectionStatus.Connecting
connectionStatus = .Disconnected

switch connectionStatus {

    case .Disconnected:
    print("Disconnected")

    case .Connecting:
    print("Connecting")

    case .Connected:
    print("Connected")

    default:
    print("Unknown Status")
}

輸出：

Disconnected

這是我們在Swift中使用枚舉的方式。愛掏網(wǎng) - it200.com