KMPCharts/samples/ios/ChartRealtimeDemo

ChartRealtime iOS Demo

SwiftUI app consuming ChartRealtime.xcframework via Swift Package Manager.

Build

Prerequisites:

• Xcode 15+
• macOS on Apple Silicon (Intel Mac simulators are NOT supported since v0.5.0)
• Local ChartRealtime.xcframework built via Gradle

From the repo root:

./gradlew :chart-realtime:assembleChartRealtimeDebugXCFramework

This produces:

chart-realtime/build/XCFrameworks/debug/ChartRealtime.xcframework

The Package.swift references it via a local binaryTarget:

.binaryTarget(
    name: "ChartRealtime",
    path: "../../../chart-realtime/build/XCFrameworks/debug/ChartRealtime.xcframework"
)

Then resolve + build the SPM package:

cd samples/ios/ChartRealtimeDemo
swift package resolve
swift build

To run the app, open the package in Xcode (File > Open... > Package.swift) or wrap it in a thin app target. A standalone xcodeproj is intentionally NOT shipped in this scaffold.

Current limitation

chart-realtime exposes the @Composable fun RealtimeChart composable, but it does NOT yet export a ComposeUIViewController factory wrapping it into a plain UIViewController suitable for SwiftUI hosting.

Until that bridge ships (planned for v1.0.0 T1), this demo:

• Verifies the XCFramework is consumable from Swift via SPM binaryTarget
• Instantiates the full Kotlin-side public API (RealtimeChartState, ChartConfig, DataConfig, AxisConfig, RenderConfig, MinMaxLttbLodStrategy, TimeAxisFormatter, DecimalAxisFormatter, YRange.Auto, T0.FirstSample, FrameRate.Display, LineSignalRenderer, SignalConfig, ChartTheme) from SwiftUI
• Registers a signal via state.addSignal(name:signalConfig:)
• Does NOT render the actual chart

Enabling the full demo (post-v1.0.0 T1)

In chart-realtime/src/iosMain/:

import androidx.compose.ui.window.ComposeUIViewController
import platform.UIKit.UIViewController

public fun RealtimeChartViewController(
    state: RealtimeChartState,
    xWindowSeconds: Float = state.config.data.xWindowSeconds,
): UIViewController = ComposeUIViewController {
    RealtimeChart(state = state, xWindowSeconds = xWindowSeconds)
}

Then in SwiftUI:

import SwiftUI
import ChartRealtime
import UIKit

struct ChartHost: UIViewControllerRepresentable {
    let state: RealtimeChartState

    func makeUIViewController(context: Context) -> UIViewController {
        // Kotlin top-level functions are exposed under the Kt-suffixed class
        // in the auto-generated ObjC header; exact symbol depends on file name.
        return RealtimeChartViewControllerKt.RealtimeChartViewController(
            state: state,
            xWindowSeconds: 10.0
        )
    }

    func updateUIViewController(_ uiViewController: UIViewController, context: Context) {}
}

ObjC bridge gotchas observed while authoring this demo

• All Kotlin data-class constructors lose default arguments when crossing the ObjC bridge — callers must pass every constructor argument explicitly.
• Sealed-class objects (YRange.Auto, T0.FirstSample, FrameRate.Display) are exposed as classes with no-arg init(). Use YRange.Auto(), etc.
• Compose Color is bridged as uint64_t (Kotlin ULong) — pass raw ARGB packed values: 0xFF00FF88 for opaque mint green.
• LineSignalRenderer is a Kotlin object (singleton) — both LineSignalRenderer() and LineSignalRenderer.shared work in Swift.
• dataVersion is currently not exposed as a Swift-visible property of RealtimeChartState (it is a Compose MutableState<Int> not flattened by Kotlin/Native ObjC export). A var dataVersionInt: Int getter would help.

Files

• Package.swift — SPM manifest, links ChartRealtime.xcframework via local binaryTarget
• Sources/ChartRealtimeDemo/DemoApp.swift — SwiftUI @main entry point
• Sources/ChartRealtimeDemo/DemoView.swift — placeholder view + Kotlin smoke test