Kotlin 中的压缩字节 []。 Java 代码到 Kotlin

Question

I'm trying to use this Java code but converting it to Kotlin in Android Studio, but I don't find a equivalent in kotlin for setSize(..) and .length in Kotlin. Could anyone help me?

public static byte[] zipBytes(String filename, byte[] input) throws IOException {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    ZipOutputStream zos = new ZipOutputStream(baos);
    ZipEntry entry = new ZipEntry(filename);
    entry.setSize(input.length);
    zos.putNextEntry(entry);
    zos.write(input);
    zos.closeEntry();
    zos.close();
    return baos.toByteArray();
}

Answer 1

Array in Kotlin has size field instead of Java array length and size field is Int in Kotlin, but ZipEntry.setSize(long size) accepts only long . So you can do something like this:

entry.setSize(input.size.toLong())

Or in more Kotlin idiomatic way:

entry.size = input.size.toLong()

Answer 2

Try to use this code:

Import:

import java.io.IOException
import java.text.DecimalFormat
import java.util.zip.ZipEntry
import java.util.zip.ZipOutputStream

And you code in kotlin:

@Throws(IOException::class)
fun zipBytes(filename: String?, input: ByteArray): ByteArray? {
    val baos = ByteArrayOutputStream()
    val zos = ZipOutputStream(baos)
    val entry = ZipEntry(filename)
    entry.size = input.size.toLong()
    zos.putNextEntry(entry)
    zos.write(input)
    zos.closeEntry()
    zos.close()
    return baos.toByteArray()
}

Answer 3

when you write a byteArray in kotlin like this :

 val byteArray = ByteArray(1024)
 var length = byteArray.size

documentation says

An array of bytes. When targeting the JVM, instances of this class are represented as byte[] . @constructor Creates a new array of the specified [size], with all elements initialized to zero.

to prove it, checking the byte code created is this:

 byte[] byteArray = new byte[1024];
 int test = byteArray.length;

therefor in your case a can code like this.

entry.size = byteArray.size

but type of size is int and entry.size needs a long value, just add .toLong() to size for fixing this issue.