我认为这将是把一个包的所有常量放在同一个文件中的最好方法，正如在其他答案中提到的，这避免了创建伴侣对象，这使得这个性能和非常类似于Java constants类。

class Constants {
    object Analytics {
        const val PROJECT_OPEN = "project_open"
        const val PROJECT_CLOSE = "project_close"
    }

    object HTTP {
        const val BASE_URL = "x.y.com"
    }

    object DBConst {
        const val TABLE_NAME = "abc"
    }
}

这可以从这样的代码中引用，使其非常结构化。

Constants.Analytics.PROJECT_OPEN
Constants.HTTP.BASE_URL
Constants.DBConst.TABLE_NAME

避免使用伴随对象。在底层，为可访问的字段创建了getter和setter实例方法。从技术上讲，调用实例方法比调用静态方法代价更大。

public class DbConstants {
    companion object {
        val TABLE_USER_ATTRIBUTE_EMPID = "_id"
        val TABLE_USER_ATTRIBUTE_DATA = "data"
    }

而是在object中定义常量。

推荐的做法:

object DbConstants {
    const val TABLE_USER_ATTRIBUTE_EMPID = "_id"
    const val TABLE_USER_ATTRIBUTE_DATA = "data"
}

并像这样全局访问它们: DbConstants。TABLE_USER_ATTRIBUTE_EMPID

在Kotlin中声明常量不需要类、对象或伴生对象。您可以声明一个包含所有常量的文件(例如constants。或者你也可以把它们放在任何现有的Kotlin文件中)，并直接在文件中声明常量。编译时已知的常量必须用const标记。

所以，在这种情况下，它应该是:

const val MY_CONST = "something"

然后你可以导入常量使用:

import package_name.MY_CONST

你可以参考这个链接

Something that isn't mentioned in any of the answers is the overhead of using companion objects. As you can read here, companion objects are in fact objects and creating them consumes resources. In addition, you may need to go through more than one getter function every time you use your constant. If all that you need is a few primitive constants on a few instances of your class, you'll probably just be better off using val to get a better performance and avoid the companion object. The trade off is higher memory consumption if you have many instances of your class so everyone should make their own decision.

TL,博士;文章:

使用伴侣对象实际上会将以下Kotlin代码:

class MyClass {

    companion object {
        private val TAG = "TAG"
    }

    fun helloWorld() {
        println(TAG)
    }
}

在这段Java代码中:

public final class MyClass {
    private static final String TAG = "TAG";
    public static final Companion companion = new Companion();

    // synthetic
    public static final String access$getTAG$cp() {
        return TAG;
    }

    public static final class Companion {
        private final String getTAG() {
            return MyClass.access$getTAG$cp();
        }

        // synthetic
        public static final String access$getTAG$p(Companion c) {
            return c.getTAG();
        }
    }

    public final void helloWorld() {
        System.out.println(Companion.access$getTAG$p(companion));
    }
}

我认为这将是把一个包的所有常量放在同一个文件中的最好方法，正如在其他答案中提到的，这避免了创建伴侣对象，这使得这个性能和非常类似于Java constants类。

class Constants {
    object Analytics {
        const val PROJECT_OPEN = "project_open"
        const val PROJECT_CLOSE = "project_close"
    }

    object HTTP {
        const val BASE_URL = "x.y.com"
    }

    object DBConst {
        const val TABLE_NAME = "abc"
    }
}

这可以从这样的代码中引用，使其非常结构化。

Constants.Analytics.PROJECT_OPEN
Constants.HTTP.BASE_URL
Constants.DBConst.TABLE_NAME

Kotlin静态和常量值&方法声明

object MyConstant {

@JvmField   // for access in java code 
val PI: Double = 3.14

@JvmStatic // JvmStatic annotation for access in java code
fun sumValue(v1: Int, v2: Int): Int {
    return v1 + v2
}

}

在任何地方访问值

val value = MyConstant.PI
val value = MyConstant.sumValue(10,5)