如何从财产中获得枚举值 [英] How to get enum value from property

问题描述

我有一个值为 VALID 和 INVALID 的枚举，它们具有与之关联的布尔属性.我想根据我提供的布尔值获取枚举值.

I have an enum with values VALID and INVALID, which have a boolean property associated with them. I would like to get the enum value based on a boolean value I provide.

如果它是 true ，我应该得到 VALID ，如果它是 false ，我应该得到 INVALID .我想根据成员变量的值，在如下所示的getter方法中这样做

If it is true I should get VALID, if it is false I should get INVALID. I would like to do so in a getter method like the below, based on the value of the member variable

public boolean getCardValidityStatus() {
    return CardValidationStatus status = CardValidationStatus(this.mCardValidityStatus));
}

我的代码:

private enum CardValidationStatus {
    VALID(true),
    INVALID(false);

    private boolean isValid;
    CardValidationStatus(boolean isValid) {
        this.isValid = isValid;
    }
    public boolean getValidityStatus() {
        return this.isValid;
    }
}

推荐答案

您可以使用枚举本身中的静态查找方法来实现这一目标:

You're able to achieve that using a static lookup method in the enum itself:

private enum CardValidationStatus {
    VALID(true),
    INVALID(false);

    //...

    public static CardValidationStatus forBoolean(boolean status) {

        //this is simplistic given that it's a boolean-based lookup
        //but it can get complex, such as using a loop...
        return status ? VALID : INVALID; 
    }
}

可以使用以下方法检索适当的状态:

And the appropriate status can be retrieved using:

public CardValidationStatus getCardValidityStatus() {
    return CardValidationStatus.forBoolean(this.mCardValidityStatus));
}

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