Merge "[PreferenceGraph] Introduce PreferenceScreenProvider" into main

packages/SettingsLib/Graph/Android.bp

+package {
+    default_applicable_licenses: ["frameworks_base_license"],
+}
+
+filegroup {
+    name: "SettingsLibGraph-srcs",
+    srcs: ["src/**/*"],
+}
+
+android_library {
+    name: "SettingsLibGraph",
+    defaults: [
+        "SettingsLintDefaults",
+    ],
+    srcs: [":SettingsLibGraph-srcs"],
+    static_libs: [
+        "androidx.annotation_annotation",
+        "androidx.preference_preference",
+    ],
+    kotlincflags: ["-Xjvm-default=all"],
+}

packages/SettingsLib/Graph/AndroidManifest.xml

+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.android.settingslib.graph">
+
+  <uses-sdk android:minSdkVersion="21" />
+</manifest>

packages/SettingsLib/Graph/src/com/android/settingslib/graph/PreferenceScreenManager.kt

+package com.android.settingslib.graph
+
+import androidx.annotation.StringRes
+import androidx.annotation.XmlRes
+import androidx.preference.Preference
+import androidx.preference.PreferenceManager
+import androidx.preference.PreferenceScreen
+
+/** Manager to create and initialize preference screen. */
+class PreferenceScreenManager(private val preferenceManager: PreferenceManager) {
+    private val context = preferenceManager.context
+    // the map will preserve order
+    private val updaters = mutableMapOf<String, PreferenceUpdater>()
+    private val screenUpdaters = mutableListOf<PreferenceScreenUpdater>()
+
+    /** Creates an empty [PreferenceScreen]. */
+    fun createPreferenceScreen(): PreferenceScreen =
+        preferenceManager.createPreferenceScreen(context)
+
+    /** Creates [PreferenceScreen] from resource. */
+    fun createPreferenceScreen(@XmlRes xmlRes: Int): PreferenceScreen =
+        preferenceManager.inflateFromResource(context, xmlRes, null)
+
+    /** Adds updater for given preference. */
+    fun addPreferenceUpdater(@StringRes key: Int, updater: PreferenceUpdater) =
+        addPreferenceUpdater(context.getString(key), updater)
+
+    /** Adds updater for given preference. */
+    fun addPreferenceUpdater(
+        key: String,
+        updater: PreferenceUpdater,
+    ): PreferenceScreenManager {
+        updaters.put(key, updater)?.let { if (it != updater) throw IllegalArgumentException() }
+        return this
+    }
+
+    /** Adds updater for preference screen. */
+    fun addPreferenceScreenUpdater(updater: PreferenceScreenUpdater): PreferenceScreenManager {
+        screenUpdaters.add(updater)
+        return this
+    }
+
+    /** Adds a list of updaters for preference screen. */
+    fun addPreferenceScreenUpdater(
+        vararg updaters: PreferenceScreenUpdater,
+    ): PreferenceScreenManager {
+        screenUpdaters.addAll(updaters)
+        return this
+    }
+
+    /** Updates preference screen with registered updaters. */
+    fun updatePreferenceScreen(preferenceScreen: PreferenceScreen) {
+        for ((key, updater) in updaters) {
+            preferenceScreen.findPreference<Preference>(key)?.let { updater.updatePreference(it) }
+        }
+        for (updater in screenUpdaters) {
+            updater.updatePreferenceScreen(preferenceScreen)
+        }
+    }
+}
+
+/** Updater of [Preference]. */
+interface PreferenceUpdater {
+    fun updatePreference(preference: Preference)
+}
+
+/** Updater of [PreferenceScreen]. */
+interface PreferenceScreenUpdater {
+    fun updatePreferenceScreen(preferenceScreen: PreferenceScreen)
+}

packages/SettingsLib/Graph/src/com/android/settingslib/graph/PreferenceScreenProvider.kt

+package com.android.settingslib.graph
+
+import android.content.Context
+import androidx.preference.PreferenceScreen
+
+/**
+ * Interface to provide [PreferenceScreen].
+ *
+ * It is expected to be implemented by Activity/Fragment and the implementation needs to use
+ * [Context] APIs (e.g. `getContext()`, `getActivity()`) with caution: preference screen creation
+ * could happen in background service, where the Activity/Fragment lifecycle callbacks (`onCreate`,
+ * `onDestroy`, etc.) are not invoked.
+ */
+interface PreferenceScreenProvider {
+
+    /**
+     * Creates [PreferenceScreen].
+     *
+     * Preference screen creation could happen in background service. The implementation MUST use
+     * given [context] instead of APIs like `getContext()`, `getActivity()`, etc.
+     */
+    fun createPreferenceScreen(
+        context: Context,
+        preferenceScreenManager: PreferenceScreenManager,
+    ): PreferenceScreen?
+}