feat: add data binding lists support

Adds ViewModelListProperty for dynamic list management at runtime.

Closes #11

Author: mfazekas

android/src/main/java/com/margelo/nitro/rive/HybridViewModelInstance.kt

@@ -73,4 +73,13 @@ class HybridViewModelInstance(val viewModelInstance: ViewModelInstance) : Hybrid
       return null
     }
   }
+
+  override fun listProperty(path: String): HybridViewModelListPropertySpec? {
+    try {
+      val listProperty = viewModelInstance.getListProperty(path)
+      return HybridViewModelListProperty(listProperty)
+    } catch (e: ViewModelException) {
+      return null
+    }
+  }
 }

android/src/main/java/com/margelo/nitro/rive/HybridViewModelListProperty.kt

@@ -0,0 +1,51 @@
+package com.margelo.nitro.rive
+
+import androidx.annotation.Keep
+import app.rive.runtime.kotlin.core.ViewModelListProperty
+import com.facebook.proguard.annotations.DoNotStrip
+import kotlinx.coroutines.flow.map
+
+@Keep
+@DoNotStrip
+class HybridViewModelListProperty(private val listProperty: ViewModelListProperty) :
+  HybridViewModelListPropertySpec(),
+  BaseHybridViewModelProperty<Unit> by BaseHybridViewModelPropertyImpl() {
+  override val length: Double
+    get() = listProperty.size.toDouble()
+
+  override fun instanceAt(index: Double): HybridViewModelInstanceSpec? {
+    return try {
+      HybridViewModelInstance(listProperty.elementAt(index.toInt()))
+    } catch (e: IndexOutOfBoundsException) {
+      null
+    }
+  }
+
+  override fun addInstance(instance: HybridViewModelInstanceSpec) {
+    val hybridInstance = instance as? HybridViewModelInstance ?: return
+    listProperty.add(hybridInstance.viewModelInstance)
+  }
+
+  override fun insertInstance(instance: HybridViewModelInstanceSpec, index: Double) {
+    val hybridInstance = instance as? HybridViewModelInstance ?: return
+    listProperty.add(index.toInt(), hybridInstance.viewModelInstance)
+  }
+
+  override fun removeInstance(instance: HybridViewModelInstanceSpec) {
+    val hybridInstance = instance as? HybridViewModelInstance ?: return
+    listProperty.remove(hybridInstance.viewModelInstance)
+  }
+
+  override fun removeInstanceAt(index: Double) {
+    listProperty.removeAt(index.toInt())
+  }
+
+  override fun swap(index1: Double, index2: Double) {
+    listProperty.swap(index1.toInt(), index2.toInt())
+  }
+
+  override fun addListener(onChanged: () -> Unit) {
+    listeners.add { onChanged() }
+    ensureValueListenerJob(listProperty.valueFlow.map { })
+  }
+}

ios/BaseHybridViewModelProperty.swift

@@ -23,6 +23,7 @@ typealias EnumPropertyType = RiveDataBindingViewModel.Instance.EnumProperty
 typealias ColorPropertyType = RiveDataBindingViewModel.Instance.ColorProperty
 typealias TriggerPropertyType = RiveDataBindingViewModel.Instance.TriggerProperty
 typealias ImagePropertyType = RiveDataBindingViewModel.Instance.ImageProperty
+typealias ListPropertyType = RiveDataBindingViewModel.Instance.ListProperty
 
 // Make all Rive property types conform to the protocol
 extension BooleanPropertyType: RivePropertyWithListeners {
@@ -56,6 +57,14 @@ extension ImagePropertyType: RivePropertyWithListeners {
   }
 }
 
+extension ListPropertyType: RivePropertyWithListeners {
+  typealias ListenerValueType = Void
+
+  func addListener(_ callback: @escaping ListenerType) -> UUID {
+    addListener { callback(()) }
+  }
+}
+
 /// Helper class for managing ViewModel property listeners
 class PropertyListenerHelper<PropertyType: RivePropertyWithListeners> {
   private var listenerIds: [UUID] = []

ios/HybridViewModelInstance.swift

@@ -48,4 +48,9 @@ class HybridViewModelInstance: HybridViewModelInstanceSpec {
     guard let property = viewModelInstance?.imageProperty(fromPath: path) else { return nil }
     return HybridViewModelImageProperty(property: property)
   }
+
+  func listProperty(path: String) throws -> (any HybridViewModelListPropertySpec)? {
+    guard let property = viewModelInstance?.listProperty(fromPath: path) else { return nil }
+    return HybridViewModelListProperty(property: property)
+  }
 }

ios/HybridViewModelListProperty.swift

@@ -0,0 +1,54 @@
+import RiveRuntime
+
+class HybridViewModelListProperty: HybridViewModelListPropertySpec, ValuedPropertyProtocol {
+  var property: ListPropertyType!
+  lazy var helper = PropertyListenerHelper(property: property!)
+
+  init(property: ListPropertyType) {
+    self.property = property
+    super.init()
+  }
+
+  override init() {
+    super.init()
+  }
+
+  var length: Double {
+    Double(property.count)
+  }
+
+  func instanceAt(index: Double) throws -> (any HybridViewModelInstanceSpec)? {
+    guard let instance = property.instance(at: Int(index)) else { return nil }
+    return HybridViewModelInstance(viewModelInstance: instance)
+  }
+
+  func addInstance(instance: any HybridViewModelInstanceSpec) throws {
+    guard let hybridInstance = instance as? HybridViewModelInstance,
+          let viewModelInstance = hybridInstance.viewModelInstance else { return }
+    property.addInstance(viewModelInstance)
+  }
+
+  func insertInstance(instance: any HybridViewModelInstanceSpec, index: Double) throws {
+    guard let hybridInstance = instance as? HybridViewModelInstance,
+          let viewModelInstance = hybridInstance.viewModelInstance else { return }
+    _ = property.insertInstance(viewModelInstance, at: Int(index))
+  }
+
+  func removeInstance(instance: any HybridViewModelInstanceSpec) throws {
+    guard let hybridInstance = instance as? HybridViewModelInstance,
+          let viewModelInstance = hybridInstance.viewModelInstance else { return }
+    property.removeInstance(viewModelInstance)
+  }
+
+  func removeInstanceAt(index: Double) throws {
+    property.removeInstance(at: Int(index))
+  }
+
+  func swap(index1: Double, index2: Double) throws {
+    property.swapInstance(at: Int(index1), withInstanceAt: Int(index2))
+  }
+
+  func addListener(onChanged: @escaping () -> Void) throws {
+    try addListener(onChanged: { _ in onChanged() })
+  }
+}