Kotlin 中类和对象的区别

问题描述

我是 Kotlin 的新手，最近将一个简单的文件从 Java 转换为 Kotlin.我想知道为什么 Android 转换器将我的 java 类更改为 Kotlin 对象.

I'm new to Kotlin and have recently converted a simple file from java to Kotlin. I am wondering why the Android converter changed my java class to a Kotlin object.

Java:

public class MyClass {
    static public int GenerateChecksumCrc16(byte bytes[]) {

        int crc = 0xFFFF;
        int temp;
        int crc_byte;

        for (byte aByte : bytes) {

            crc_byte = aByte;

            for (int bit_index = 0; bit_index < 8; bit_index++) {

                temp = ((crc >> 15)) ^ ((crc_byte >> 7));

                crc <<= 1;
                crc &= 0xFFFF;

                if (temp > 0) {
                    crc ^= 0x1021;
                    crc &= 0xFFFF;
                }

                crc_byte <<= 1;
                crc_byte &= 0xFF;

            }
        }

        return crc;
    }
}

转换后的 Kotlin:

Converted Kotlin:

object MyClass {
    fun GenerateChecksumCrc16(bytes: ByteArray): Int {

        var crc = 0xFFFF
        var temp: Int
        var crc_byte: Int

        for (aByte in bytes) {

            crc_byte = aByte.toInt()

            for (bit_index in 0..7) {

                temp = crc shr 15 xor (crc_byte shr 7)

                crc = crc shl 1
                crc = crc and 0xFFFF

                if (temp > 0) {
                    crc = crc xor 0x1021
                    crc = crc and 0xFFFF
                }

                crc_byte = crc_byte shl 1
                crc_byte = crc_byte and 0xFF

            }
        }

        return crc
    }
}

为什么不是:

class MyClass {
    ... etc ...
}

非常感谢任何帮助.

推荐答案

Kotlin 对象就像一个无法实例化的类，因此必须按名称调用它.(一个静态类本身)

A Kotlin object is like a class that can't be instantiated so it must be called by name. (a static class per se)

android 转换器看到您的类仅包含一个静态方法，因此将其转换为 Kotlin 对象.

The android converter saw that your class contained only a static method, so it converted it to a Kotlin object.

在此处阅读更多相关信息:http://petersommerhoff.com/dev/kotlin/kotlin-for-java-devs/#objects

Read more about it here: http://petersommerhoff.com/dev/kotlin/kotlin-for-java-devs/#objects

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