KONFeature · June 28, 2022 21:34 · Jun 28, 2022
diff --git a/ComposeOverlayViewService.kt b/ComposeOverlayViewService.kt
@@ -0,0 +1,105 @@
+import android.content.Intent
+import android.graphics.PixelFormat
+import android.os.IBinder
+import android.view.Gravity
+import android.view.WindowManager
+import androidx.compose.foundation.gestures.detectDragGestures
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.BoxScope
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.input.pointer.consumeAllChanges
+import androidx.compose.ui.input.pointer.pointerInput
+import androidx.compose.ui.platform.ComposeView
+import androidx.lifecycle.ViewTreeLifecycleOwner
+import androidx.lifecycle.ViewTreeViewModelStoreOwner
+import androidx.savedstate.setViewTreeSavedStateRegistryOwner
+import kotlin.math.roundToInt
+
+/**
+ * Service that is ready to display compose overlay view
+ * @author Quentin Nivelais
+ */
+abstract class ComposeOverlayViewService : ViewReadyService() {
+
+    // Build the layout param for our popup
+    private val layoutParams by lazy {
+        WindowManager.LayoutParams(
+            WindowManager.LayoutParams.WRAP_CONTENT,
+            WindowManager.LayoutParams.WRAP_CONTENT,
+            WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY,
+            WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
+            PixelFormat.TRANSLUCENT
+        ).apply {
+            gravity = Gravity.TOP or Gravity.CENTER_HORIZONTAL
+        }
+    }
+
+    // The current offset of our overlay composable
+    private var overlayOffset by mutableStateOf(Offset.Zero)
+
+    // Access our window manager
+    private val windowManager by lazy {
+        overlayContext.getSystemService(WindowManager::class.java)
+    }
+
+    // Build our compose view
+    private val composeView by lazy {
+        ComposeView(overlayContext)
+    }
+
+    override fun onBind(intent: Intent): IBinder? = null
+
+    override fun onCreate() {
+        super.onCreate()
+
+        // Bound the compose lifecycle, view model and view tree saved state, into our view service
+        ViewTreeLifecycleOwner.set(composeView, this)
+        ViewTreeViewModelStoreOwner.set(composeView) { viewModelStore }
+        composeView.setViewTreeSavedStateRegistryOwner(this)
+
+        // Set the content of our compose view
+        composeView.setContent { Content() }
+
+        // Push the compose view into our window manager
+        windowManager.addView(composeView, layoutParams)
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        // Remove our compose view from the window manager
+        windowManager.removeView(composeView)
+    }
+
+    @Composable
+    abstract fun Content()
+
+    /**
+     * Draggable box container (not used by default, since not every overlay should be draggable)
+     */
+    @Composable
+    internal fun OverlayDraggableContainer(modifier: Modifier = Modifier, content: @Composable BoxScope.() -> Unit) =
+        Box(
+            modifier = modifier.pointerInput(Unit) {
+                detectDragGestures { change, dragAmount ->
+                    change.consumeAllChanges()
+
+                    // Update our current offset
+                    val newOffset = overlayOffset + dragAmount
+                    overlayOffset = newOffset
+
+                    // Update the layout params, and then the view
+                    layoutParams.apply {
+                        x = overlayOffset.x.roundToInt()
+                        y = overlayOffset.y.roundToInt()
+                    }
+                    windowManager.updateViewLayout(composeView, layoutParams)
+                }
+            },
+            content = content
+        )
+}
diff --git a/MyComposeDraggableOverlayService.kt b/MyComposeDraggableOverlayService.kt
@@ -0,0 +1,9 @@
+class MyComposeOverlayService : ComposeOverlayViewService() {
+
+    override fun onBind(intent: Intent): IBinder? = null
+
+    @Composable
+    override fun Content() = OverlayDraggableContainer {
+        Text("My super component")
+    }
+}
diff --git a/ViewReadyService.kt b/ViewReadyService.kt
@@ -0,0 +1,57 @@
+import android.content.Context
+import android.hardware.display.DisplayManager
+import android.view.Display
+import android.view.WindowManager
+import androidx.lifecycle.LifecycleService
+import androidx.lifecycle.ViewModelStore
+import androidx.lifecycle.ViewModelStoreOwner
+import androidx.savedstate.SavedStateRegistry
+import androidx.savedstate.SavedStateRegistryController
+import androidx.savedstate.SavedStateRegistryOwner
+
+/**
+ * Service that is ready to display view, provide a ui context on the primary screen, and all the tools needed to built a view with state managment, view model etc
+ * @author Quentin Nivelais
+ */
+abstract class ViewReadyService : LifecycleService(), SavedStateRegistryOwner, ViewModelStoreOwner {
+
+    /**
+     * Build our saved state registry controller
+     */
+    private val savedStateRegistryController: SavedStateRegistryController by lazy(LazyThreadSafetyMode.NONE) {
+        SavedStateRegistryController.create(this)
+    }
+
+    /**
+     * Build our view model store
+     */
+    private val internalViewModelStore: ViewModelStore by lazy {
+        ViewModelStore()
+    }
+
+    /**
+     * Context dedicated to the view
+     */
+    internal val overlayContext: Context by lazy {
+        // Get the default display
+        val defaultDisplay: Display = getSystemService(DisplayManager::class.java).getDisplay(Display.DEFAULT_DISPLAY)
+        // Create a display context, and then the window context
+        createDisplayContext(defaultDisplay)
+            .createWindowContext(WindowManager.LayoutParams.TYPE_APPLICATION_OVERLAY, null)
+    }
+
+    override fun onCreate() {
+        super.onCreate()
+        // Restore the last saved state registry
+        savedStateRegistryController.performRestore(null)
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+    }
+
+    override val savedStateRegistry: SavedStateRegistry
+        get() = savedStateRegistryController.savedStateRegistry
+
+    override fun getViewModelStore(): ViewModelStore = internalViewModelStore
+}
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