Best way to use BufferedReader in Kotlin

Question

So I've just started using Kotlin for Android, and converted my Android Java codes into Kotlin.

In one of the conversions, I stumbled upon a BufferedReader, which I would usually write in Java as the following:

String result = ""; String line = ""; BufferedReader reader = new BufferedReader(someStream); while ( (line = reader.readLine()) != null ) {     result += line; } 

But in Kotlin, it seems that Kotlin doesn't allow me to assign values to variables in while conditions.

Currently, I've written the code as the following:

val reader = BufferedReader(someStream) var line : String? = "" while (line != null) {     line = reader.readLine()     result += line } 

which I don't find so elegant and feels prev-gen, despite using Kotlin.

What would be the best way to use BufferedReader in Kotlin?

Answer 1

If you still wanted to read it line by line you could use some extension functions from std lib and do it as follows:

val reader = someStream.bufferedReader() val iterator = reader.linesSequences().iterator() while(iterator.hasNext()) {     val line = iterator.next()     // do something with line... } reader.close() 

or alternatively, using a "functional" approach:

val reader = someStream.bufferedReader() reader.useLines {     it.map { line -> // do something with line } } 

by using useLines, you don't need to explicitly call close on the reader, the useLines extensions function will do it for you!

Just adding those for reference.. cheers

Answer 2

You can use bufferedReader like so

val allText = inputStream.bufferedReader().use(BufferedReader::readText)