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Use External Dependencies

How It works

On completion with the basic configuration, it's possible to use external dependency with your bridge.

The plug-in uses the Swift Packages features to gather all dependency inside the bridge.

Note

If your package doesn't work with the plugin, please create an issue.

Automatic Dependency Build Inclusion

The plugin will automatically include the dependency requirement in your application, if possible.

Also, it can detect if the dependency must be included in your Xcode project, BUT the detection is not 100% accurate.

I have a build error or runtime crash from my native dependency

If you encounter during the compilation an error like Undefined symbol: ... or a dependency crash during the runtime please follow the steps below.

  • Run your application on Xcode and check for errors

    • If you have a Undefined symbol build error, you MUST add your dependency to Xcode
    • If you have objc/C++/C runtime crash , you MUST add your dependency to Xcode

  • You have two choices:

    • Use the includeProduct option to generate a local package to include in your Xcode project
      • Your Xcode project will be automatically synched with the required dependency
    • Manually add the dependency to your Xcode project

Use Dependencies In Your Application

By default, the dependencies are not available from your application, but if you need them, you can add them inside the includeProduct configuration, and then the dependency will be included inside a local package.

Local Package

If the dependencies must be declared on the Xcode side; in that case, you will see the following message during the build: 

Spm4Kmp: The following dependencies [some_dependency_name] need to be added to your xcode project
A local Swift package has been generated at
/path/to/the/local/package
Please add it to your xcode project as a local package dependency; it will add the missing content.
****You can ignore this messaging if you have already added these dependencies to your Xcode project****

Example

Gradle

The following configuration imports the package CryptoSwift which is a pure Swift library, that can't be used directly in Kotlin.

build.gradle.kts
swiftPackageConfig {
    create("[cinteropName]") {
        dependency {
            remotePackageVersion(
                url = uri("https://github.com/krzyzanowskim/CryptoSwift.git"),
                products = {
                    add("CryptoSwift")
                },
                version = "1.8.4",
            )
            // Another SwiftDependency
            // ...
        }
    }
}

Bridge

Make your Swift code compatible with Kotlin.

Your Swift code needs to be marked as @objc/@objcMembers and the visibility set as public or it won't be exported and available from your Kotlin code.

src/swift/[cinteropname]/mySwiftFile.swift
import Foundation
import CryptoSwift

@objcMembers public class MySwiftBridge: NSObject {
    public func toMD5(value: String) -> String {
        return value.md5()
    }
}
iosMain/kotlin/com/example/myKotlinFile.kt
import [cinteropname].MySwiftBridge

val contentFromSwift = MySwiftBridge().toMD5(value = "someString")

Supported Dependency Sources

The plugin supports the following configurations :

remotePackageVersion(
    url = uri("https://github.com/krzyzanowskim/CryptoSwift.git"),
    version = "1.8.4",
    products = {
        add("CryptoSwift")
    },
)

remotePackageCommit(
    url = uri("https://github.com/krzyzanowskim/CryptoSwift.git"),
    revision = "729e01bc9b9dab466ac85f21fb9ee2bc1c61b258",
    products = {
        add("CryptoSwift")
    },
)

remotePackageBranch(
    url = uri("https://github.com/krzyzanowskim/CryptoSwift.git"),
    branch = "main",
    products = {
        add("CryptoSwift")
    },
),

localPackage(
    path = "Absolute path to the local package folder",
    packageName = "LocalSourceDummyFramework",
    products = {
        add("LocalSourceDummyFramework")
    },
),

localBinary(
    path = "/path/to/LocalFramework.xcframework",
    packageName = "LocalFramework"
),

remoteBinary(
    url = uri("https://.../RemoteBinaryFramework.xcframework.zip"),
    checksum = "[checksum]",
    packageName = "RemoteBinaryFramework",
)

SwiftDependency reference

XCFramework

The XCFrameworks are used for Local/Remote Binary and protecting source code distribution, learn more.

An example is available.