检查会员/财产类型 [英] Check type of member/property

问题描述

假设我有任何一门课，像这样一课:

Let's say i have any class, like this one:

class SomeClass(val aThing: String, val otherThing: Double)

然后，我使用反射来分析此类的字段:

Then I use reflection to analyze the fields of this class:

for(field in SomeClass.declaredMemberProperties){

}

如何检查每个字段的类型?

How can I check the type of each field?

推荐答案

由于Kotlin没有字段，而只有带有支持字段的属性，因此应检查该属性的返回类型.

Since Kotlin does not have fields but only properties with backing fields, you should check the return type of the property.

尝试一下:

    class SomeClass(val aThing: String, val otherThing: Double)

    for(property in SomeClass::class.declaredMemberProperties) {
        println("${property.name} ${property.returnType}")
    }

更新:

如果该类在没有后备字段的情况下不使用自定义getter和/或setter，则可以这样获取后备字段的类型:

If the class does not use custom getters and/or setters without backing fields, you can get the type of the backing field like this:

property.javaField?.type

作为一个完整的示例，这是您的类，带有一个名为foo的附加val属性，该属性带有自定义getter(因此不会创建任何后备字段).您将看到该属性的getJavaField()将返回null.

As a complete example, here is your class with an additional val property called foo with a custom getter (so no backing field is created). You will see that getJavaField() of that property will return null.

    class SomeClass(val aThing: String, val otherThing: Double) {
        val foo : String
            get() = "foo"
    }

    for(property in SomeClass::class.declaredMemberProperties) {
        println("${property.name} ${property.returnType} ${property.javaField?.type}")
    }

UPDATE2:

使用String::class.createType()将为每个KClass返回KType，因此您可以使用例如property.returnType == String::class.createType()查明它是否是(kotlin)字符串.

Using String::class.createType() will return the KType for every KClass, so you can use e.g. property.returnType == String::class.createType() to find out if it's a (kotlin) String.

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