Question

这样可以在Android中使用Enum吗？

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

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

从外部代码我只能访问EventAction.SDCARD_MOUNTED.toString（），但.getCode（）不可见。我看到的示例显示了如何从代码内部使用getCode（）。

Answer 1

将getCode()声明为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();

}

如果每个值都以相同的方式实现，那么这样做更清楚：

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

您需要在枚举级别声明方法：

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;
    }
}

主

中的

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

输出：

External SDCard was mounted
25
External SDCard was mounted 111111111
50

我可以在Java枚举中添加一个返回方法吗？

3 个答案: