Java枚舉可以添加一個返回方法嗎？

Question

是否可以像這樣在Android中使用Enum？

public enum EventAction 
{ 
    SDCARD_MOUNTED 
    { 
    public String toString() { 
     return "External SDCard was mounted"; 
    } 

    public int getCode() { 
     return 25; 
    } 
    } 
} 

從外部的代碼我只有EventAction.SDCARD_MOUNTED.toString（），但.getCode（）的訪問是不可見的。我看到的例子展示瞭如何從代碼中使用getCode（）。

Answer 1

申報getCode()作爲abstract方法：

public enum EventAction 
{ 
    SDCARD_MOUNTED 
    { 
    @Override 
    public String toString() { 
     return "External SDCard was mounted"; 
    } 
    @Override 
    public int getCode() { 
     return 25; 
    } 
    }; 

    public abstract int getCode(); 

} 

如果每個值將被實施以同樣的方式，它更清晰做到這一點：

public enum EventAction { 
    SDCARD_MOUNTED(25, "External SDCard was mounted"); 
    private final int code; 
    private final String message; 
    private EventAction(int code, String message) { 
    this.code = code; 
    this.message = message; 
    } 
    @Override 
    public String toString() { return message; } 
    public int getCode() { return code; } 
} 

Answer 2

您需要在申報的方法枚舉級別：

public enum EventAction 
{ 
    SDCARD_MOUNTED 
    { 
    public String toString() { 
     return "External SDCard was mounted"; 
    } 

    public int getCode() { 
     return 25; 
    } 
    }; 

    public abstract int getCode(); 

} 

Answer 3

public enum EventAction 
{ 
    SDCARD_MOUNTED("External SDCard was mounted",25), 
    SDCARD_MOUNTED_1("External SDCard was mounted 111111111",50); 

    private String details; 
    private int code; 

    private EventAction(String details,int code){ 
     this.code = code; 
     this.details = details; 
    } 

    public String toString() { 
     return this.details; 
    } 

    public int getCode() { 
     return this.code; 
    } 
} 

在主

System.out.println(EventAction.SDCARD_MOUNTED.toString()); 
System.out.println(EventAction.SDCARD_MOUNTED.getCode()); 

OUTPUT：

External SDCard was mounted 
25 
External SDCard was mounted 111111111 
50