1 files changed, 95 insertions, 0 deletions
diff --git a/src/com/android/launcher3/util/WallpaperColorHints.kt b/src/com/android/launcher3/util/WallpaperColorHints.kt
new file mode 100644
index 0000000000..1361c1ed21
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+++ b/src/com/android/launcher3/util/WallpaperColorHints.kt
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.launcher3.util
+
+import android.app.WallpaperColors
+import android.app.WallpaperManager
+import android.app.WallpaperManager.FLAG_SYSTEM
+import android.app.WallpaperManager.OnColorsChangedListener
+import android.content.Context
+import androidx.annotation.MainThread
+import androidx.annotation.VisibleForTesting
+import com.android.launcher3.Utilities
+import com.android.launcher3.util.Executors.MAIN_EXECUTOR
+import com.android.launcher3.util.Executors.UI_HELPER_EXECUTOR
+
+/**
+ * This class caches the system's wallpaper color hints for use by other classes as a performance
+ * enhancer. It also centralizes all the WallpaperManager color hint code in one location.
+ */
+class WallpaperColorHints(private val context: Context) : SafeCloseable {
+    var hints: Int = 0
+        private set
+    private val wallpaperManager
+        get() = context.getSystemService(WallpaperManager::class.java)!!
+    private val onColorHintsChangedListeners = mutableListOf<OnColorHintListener>()
+    private val onClose: SafeCloseable
+
+    init {
+        if (Utilities.ATLEAST_S) {
+            hints = wallpaperManager.getWallpaperColors(FLAG_SYSTEM)?.colorHints ?: 0
+            val onColorsChangedListener = OnColorsChangedListener { colors, which ->
+                onColorsChanged(colors, which)
+            }
+            UI_HELPER_EXECUTOR.execute {
+                wallpaperManager.addOnColorsChangedListener(
+                    onColorsChangedListener,
+                    MAIN_EXECUTOR.handler
+                )
+            }
+            onClose = SafeCloseable {
+                UI_HELPER_EXECUTOR.execute {
+                    wallpaperManager.removeOnColorsChangedListener(onColorsChangedListener)
+                }
+            }
+        } else {
+            onClose = SafeCloseable {}
+        }
+    }
+
+    @MainThread
+    private fun onColorsChanged(colors: WallpaperColors?, which: Int) {
+        if ((which and FLAG_SYSTEM) != 0 && Utilities.ATLEAST_S) {
+            val newHints = colors?.colorHints ?: 0
+            if (newHints != hints) {
+                hints = newHints
+                onColorHintsChangedListeners.forEach { it.onColorHintsChanged(newHints) }
+            }
+        }
+    }
+
+    override fun close() = onClose.close()
+
+    fun registerOnColorHintsChangedListener(listener: OnColorHintListener) {
+        onColorHintsChangedListeners.add(listener)
+    }
+
+    fun unregisterOnColorsChangedListener(listener: OnColorHintListener) {
+        onColorHintsChangedListeners.remove(listener)
+    }
+
+    companion object {
+        @VisibleForTesting
+        @JvmField
+        val INSTANCE = MainThreadInitializedObject { WallpaperColorHints(it) }
+        @JvmStatic fun get(context: Context): WallpaperColorHints = INSTANCE.get(context)
+    }
+}
+
+interface OnColorHintListener {
+    fun onColorHintsChanged(colorHints: Int)
+}