PlatformFile

Cross-platform file representation for Kotlin Multiplatform

Supported on Android, iOS, macOS, JVM, JS and WASM targets

Introduction

PlatformFile is the core class in FileKit that provides a unified representation of files across all platforms. It abstracts away platform-specific file implementations and provides a consistent API for working with files in your Kotlin Multiplatform project.

Creating a PlatformFile

You can create a PlatformFile instance in several ways:

// From a path string
val file = PlatformFile("/path/to/file.txt")

// From a kotlinx.io.files.Path
val path = Path("/path/to/file.txt")
val file = PlatformFile(path)

// From a parent file and child path
val parentDir = PlatformFile("/path/to")
val file = PlatformFile(parentDir, "file.txt")
// or using the convenient / operator
val file = parentDir / "file.txt"

Platform-specific constructors

Each platform also provides specific constructors:

Android

// From a Java File
val javaFile = File("/path/to/file.txt")
val file = PlatformFile(javaFile)

// From an Android Uri
val uri = Uri.parse("content://...")
val file = PlatformFile(uri)

Properties

PlatformFile provides several properties to access file information:

val file = PlatformFile("/path/to/document.pdf")

// Get the file name with extension
val name: String = file.name // "document.pdf"

// Get just the file extension
val extension: String = file.extension // "pdf"

// Get the file name without extension
val nameWithoutExtension: String = file.nameWithoutExtension // "document"

// Get the file path
val path: String = file.path // "/path/to/document.pdf"

// Get the file size in bytes
val size: Long = file.size()

// Get the parent directory
val parent: PlatformFile? = file.parent()

// Get the absolute path string
val absolutePath: String = file.absolutePath()

// Get the absolute file
val absoluteFile: PlatformFile = file.absoluteFile()

File operations

PlatformFile provides methods for common file operations:

// Check if the file exists
val exists: Boolean = file.exists()

// Check if it's a regular file
val isFile: Boolean = file.isRegularFile()

// Check if it's a directory
val isDirectory: Boolean = file.isDirectory()

// Check if it's an absolute path
val isAbsolute: Boolean = file.isAbsolute()

// Create directories
file.createDirectories()

// Copy the file to a new location
file.copyTo(newFile)

// Move the file to a new location
file.atomicMove(newFile)

// Delete the file
file.delete()

// List files in the directory
val files: List<PlatformFile> = file.list()

// Get input stream as a source
val source: RawSource = file.source()

// Get output stream as a sink
val sink: RawSink = file.sink(append = false)

// Read bytes from the file
val bytes: ByteArray = file.readBytes()

// Read string from the file
val content: String = file.readString()

// Write bytes to the file
file.write(bytes)

// Write string to the file
file.writeString(content)

Working with directories

You can use the resolve method or the / operator to navigate through directories:

val baseDir = PlatformFile("/path/to/base")

// Create a reference to a subdirectory or file
val subDir = baseDir / "subdirectory"
val file = subDir / "file.txt"

// Alternative using resolve
val file2 = baseDir.resolve("subdirectory/file.txt")

// Get the absolute path from a relative path
val relativeDir = PlatformFile("/path/to/relative")
val absoluteDir: PlatformFile = relativeDir.absoluteFile()

Converting to kotlinx-io

PlatformFile provides built-in integration with kotlinx-io.

// Convert to kotlinx.io.files.Path
val path: Path = file.toKotlinxIoPath()

// Convert to kotlinx.io.RawSource
val source: RawSource = file.source()

// Convert to kotlinx.io.RawSink
val sink: RawSink = file.sink()

Example usage

// Create a file reference
val file = PlatformFile(FileKit.filesDir, "document.txt")

// Check if it exists
if (!file.exists()) {
    // Write content to the file
    file.writeString("Hello, FileKit!")
}

// Read the file content
val content = file.readString()
println(content) // "Hello, FileKit!"

Next steps

Read File

Read files as bytes, strings, or streams across platforms.

Write File

Write data to files with atomic operations and appending.

Image Utils

Compress, resize and save images with platform-specific optimizations.

File Utils

Access standard directories and common file operations.

Assistant

Responses are generated using AI and may contain mistakes.