migrate custom widgets in comply with plugin framework

Bug: 139888225
Change-Id: I8a3d0fe2689ad5ba24b19309728bbad0b6287f71
diff --git a/res/values/attrs.xml b/res/values/attrs.xml
index 69b8c8a..2b265fa 100644
--- a/res/values/attrs.xml
+++ b/res/values/attrs.xml
@@ -152,21 +152,6 @@
         <attr name="canThumbDetach" format="boolean" />
     </declare-styleable>
 
-    <declare-styleable name="CustomAppWidgetProviderInfo">
-        <attr name="providerId" format="integer" />
-
-        <attr name="android:label" />
-        <attr name="android:initialLayout" />
-        <attr name="android:icon" />
-        <attr name="android:previewImage" />
-        <attr name="android:resizeMode" />
-
-        <attr name="numRows" />
-        <attr name="numColumns" />
-        <attr name="numMinRows" format="integer" />
-        <attr name="numMinColumns" format="integer" />
-    </declare-styleable>
-
     <declare-styleable name="PreviewFragment">
         <attr name="android:name" />
         <attr name="android:id" />
diff --git a/res/xml/custom_widgets.xml b/res/xml/custom_widgets.xml
deleted file mode 100644
index 4b54386..0000000
--- a/res/xml/custom_widgets.xml
+++ /dev/null
@@ -1,31 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!--
-     Copyright (C) 2017 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.
--->
-
-<widgets>
-    <!-- Sample widget definition
-        <widget
-            android:label="My custom widget"
-            android:initialLayout="@layout/sample_widget_layout"
-            android:icon="@drawable/ic_launcher_home"
-            android:resizeMode="horizontal|vertical"
-            launcher:numRows="2"
-            launcher:numColumns="3"
-            launcher:numMinRows="1"
-            launcher:numMinColumns="2"
-            launcher:providerId="1" />
-    -->
-</widgets>
\ No newline at end of file
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index aa02441..ea58687 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -147,7 +147,7 @@
 import com.android.launcher3.widget.WidgetHostViewLoader;
 import com.android.launcher3.widget.WidgetListRowEntry;
 import com.android.launcher3.widget.WidgetsFullSheet;
-import com.android.launcher3.widget.custom.CustomWidgetParser;
+import com.android.launcher3.widget.custom.CustomWidgetManager;
 
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
@@ -1657,10 +1657,9 @@
         } else {
             // In this case, we either need to start an activity to get permission to bind
             // the widget, or we need to start an activity to configure the widget, or both.
-            if (FeatureFlags.ENABLE_CUSTOM_WIDGETS &&
-                    info.itemType == LauncherSettings.Favorites.ITEM_TYPE_CUSTOM_APPWIDGET) {
-                appWidgetId = CustomWidgetParser.getWidgetIdForCustomProvider(
-                        this, info.componentName);
+            if (info.itemType == LauncherSettings.Favorites.ITEM_TYPE_CUSTOM_APPWIDGET) {
+                appWidgetId = CustomWidgetManager.INSTANCE.get(this).getWidgetIdForCustomProvider(
+                        info.componentName);
             } else {
                 appWidgetId = getAppWidgetHost().allocateAppWidgetId();
             }
diff --git a/src/com/android/launcher3/LauncherAppState.java b/src/com/android/launcher3/LauncherAppState.java
index 2a801d6..82b1ea7 100644
--- a/src/com/android/launcher3/LauncherAppState.java
+++ b/src/com/android/launcher3/LauncherAppState.java
@@ -37,6 +37,7 @@
 import com.android.launcher3.util.MainThreadInitializedObject;
 import com.android.launcher3.util.Preconditions;
 import com.android.launcher3.util.SecureSettingsObserver;
+import com.android.launcher3.widget.custom.CustomWidgetManager;
 
 public class LauncherAppState {
 
@@ -148,6 +149,8 @@
     LauncherModel setLauncher(Launcher launcher) {
         getLocalProvider(mContext).setLauncherProviderChangeListener(launcher);
         mModel.initialize(launcher);
+        CustomWidgetManager.INSTANCE.get(launcher)
+                .setWidgetRefreshCallback(mModel::refreshAndBindWidgetsAndShortcuts);
         return mModel;
     }
 
diff --git a/src/com/android/launcher3/LauncherAppWidgetHost.java b/src/com/android/launcher3/LauncherAppWidgetHost.java
index 7f5ac52..1139f29 100644
--- a/src/com/android/launcher3/LauncherAppWidgetHost.java
+++ b/src/com/android/launcher3/LauncherAppWidgetHost.java
@@ -27,12 +27,12 @@
 import android.content.Intent;
 import android.os.Handler;
 import android.util.SparseArray;
-import android.view.LayoutInflater;
 import android.widget.Toast;
 
 import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.widget.DeferredAppWidgetHostView;
 import com.android.launcher3.widget.LauncherAppWidgetHostView;
+import com.android.launcher3.widget.custom.CustomWidgetManager;
 
 import java.util.ArrayList;
 
@@ -180,10 +180,8 @@
             LauncherAppWidgetProviderInfo appWidget) {
         if (appWidget.isCustomWidget()) {
             LauncherAppWidgetHostView lahv = new LauncherAppWidgetHostView(context);
-            LayoutInflater inflater = (LayoutInflater)
-                    context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
-            inflater.inflate(appWidget.initialLayout, lahv);
             lahv.setAppWidget(0, appWidget);
+            CustomWidgetManager.INSTANCE.get(context).onViewCreated(lahv);
             return lahv;
         } else if ((mFlags & FLAG_LISTENING) == 0) {
             DeferredAppWidgetHostView view = new DeferredAppWidgetHostView(context);
diff --git a/src/com/android/launcher3/LauncherModel.java b/src/com/android/launcher3/LauncherModel.java
index da9617a..8433a91 100644
--- a/src/com/android/launcher3/LauncherModel.java
+++ b/src/com/android/launcher3/LauncherModel.java
@@ -523,5 +523,4 @@
     public Callbacks getCallback() {
         return mCallbacks != null ? mCallbacks.get() : null;
     }
-
 }
diff --git a/src/com/android/launcher3/compat/AppWidgetManagerCompat.java b/src/com/android/launcher3/compat/AppWidgetManagerCompat.java
index 3243256..fc5d11c 100644
--- a/src/com/android/launcher3/compat/AppWidgetManagerCompat.java
+++ b/src/com/android/launcher3/compat/AppWidgetManagerCompat.java
@@ -23,19 +23,18 @@
 import android.os.Bundle;
 import android.os.UserHandle;
 
+import androidx.annotation.Nullable;
+
 import com.android.launcher3.LauncherAppWidgetInfo;
 import com.android.launcher3.LauncherAppWidgetProviderInfo;
 import com.android.launcher3.Utilities;
-import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.util.ComponentKey;
 import com.android.launcher3.util.PackageUserKey;
-import com.android.launcher3.widget.custom.CustomWidgetParser;
+import com.android.launcher3.widget.custom.CustomWidgetManager;
 
 import java.util.HashMap;
 import java.util.List;
 
-import androidx.annotation.Nullable;
-
 public abstract class AppWidgetManagerCompat {
 
     private static final Object sInstanceLock = new Object();
@@ -63,11 +62,9 @@
     }
 
     public LauncherAppWidgetProviderInfo getLauncherAppWidgetInfo(int appWidgetId) {
-        if (FeatureFlags.ENABLE_CUSTOM_WIDGETS
-                && appWidgetId <= LauncherAppWidgetInfo.CUSTOM_WIDGET_ID) {
-            return CustomWidgetParser.getWidgetProvider(mContext, appWidgetId);
+        if (appWidgetId <= LauncherAppWidgetInfo.CUSTOM_WIDGET_ID) {
+            return CustomWidgetManager.INSTANCE.get(mContext).getWidgetProvider(appWidgetId);
         }
-
         AppWidgetProviderInfo info = mAppWidgetManager.getAppWidgetInfo(appWidgetId);
         return info == null ? null : LauncherAppWidgetProviderInfo.fromProviderInfo(mContext, info);
     }
diff --git a/src/com/android/launcher3/compat/AppWidgetManagerCompatVL.java b/src/com/android/launcher3/compat/AppWidgetManagerCompatVL.java
index 1065748..c8b1f67 100644
--- a/src/com/android/launcher3/compat/AppWidgetManagerCompatVL.java
+++ b/src/com/android/launcher3/compat/AppWidgetManagerCompatVL.java
@@ -24,12 +24,15 @@
 import android.os.UserHandle;
 import android.os.UserManager;
 
+import androidx.annotation.Nullable;
+
 import com.android.launcher3.LauncherAppWidgetInfo;
 import com.android.launcher3.LauncherAppWidgetProviderInfo;
 import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.util.ComponentKey;
 import com.android.launcher3.util.PackageUserKey;
-import com.android.launcher3.widget.custom.CustomWidgetParser;
+import com.android.launcher3.widget.custom.CustomAppWidgetProviderInfo;
+import com.android.launcher3.widget.custom.CustomWidgetManager;
 
 import java.util.ArrayList;
 import java.util.Collections;
@@ -37,8 +40,6 @@
 import java.util.Iterator;
 import java.util.List;
 
-import androidx.annotation.Nullable;
-
 class AppWidgetManagerCompatVL extends AppWidgetManagerCompat {
 
     private final UserManager mUserManager;
@@ -54,14 +55,11 @@
             return Collections.emptyList();
         }
         if (packageUser == null) {
-            ArrayList<AppWidgetProviderInfo> providers = new ArrayList<AppWidgetProviderInfo>();
+            ArrayList<AppWidgetProviderInfo> providers = new ArrayList<>();
             for (UserHandle user : mUserManager.getUserProfiles()) {
                 providers.addAll(mAppWidgetManager.getInstalledProvidersForProfile(user));
             }
-
-            if (FeatureFlags.ENABLE_CUSTOM_WIDGETS) {
-                providers.addAll(CustomWidgetParser.getCustomWidgets(mContext));
-            }
+            providers.addAll(getCustomWidgets());
             return providers;
         }
         // Only get providers for the given package/user.
@@ -74,9 +72,9 @@
             }
         }
 
-        if (FeatureFlags.ENABLE_CUSTOM_WIDGETS && Process.myUserHandle().equals(packageUser.mUser)
+        if (Process.myUserHandle().equals(packageUser.mUser)
                 && mContext.getPackageName().equals(packageUser.mPackageName)) {
-            providers.addAll(CustomWidgetParser.getCustomWidgets(mContext));
+            providers.addAll(getCustomWidgets());
         }
         return providers;
     }
@@ -87,9 +85,7 @@
         if (FeatureFlags.GO_DISABLE_WIDGETS) {
             return false;
         }
-
-        if (FeatureFlags.ENABLE_CUSTOM_WIDGETS
-                && appWidgetId <= LauncherAppWidgetInfo.CUSTOM_WIDGET_ID) {
+        if (appWidgetId <= LauncherAppWidgetInfo.CUSTOM_WIDGET_ID) {
             return true;
         }
         return mAppWidgetManager.bindAppWidgetIdIfAllowed(
@@ -108,9 +104,8 @@
             }
         }
 
-        if (FeatureFlags.ENABLE_CUSTOM_WIDGETS && Process.myUserHandle().equals(user)) {
-            for (LauncherAppWidgetProviderInfo info :
-                    CustomWidgetParser.getCustomWidgets(mContext)) {
+        if (Process.myUserHandle().equals(user)) {
+            for (LauncherAppWidgetProviderInfo info : getCustomWidgets()) {
                 if (info.provider.equals(provider)) {
                     return info;
                 }
@@ -131,13 +126,13 @@
                 result.put(new ComponentKey(info.provider, user), info);
             }
         }
-
-        if (FeatureFlags.ENABLE_CUSTOM_WIDGETS) {
-            for (LauncherAppWidgetProviderInfo info :
-                    CustomWidgetParser.getCustomWidgets(mContext)) {
-                result.put(new ComponentKey(info.provider, info.getProfile()), info);
-            }
+        for (LauncherAppWidgetProviderInfo info : getCustomWidgets()) {
+            result.put(new ComponentKey(info.provider, info.getProfile()), info);
         }
         return result;
     }
+
+    List<CustomAppWidgetProviderInfo> getCustomWidgets() {
+        return CustomWidgetManager.INSTANCE.get(mContext).getCustomWidgets();
+    }
 }
diff --git a/src/com/android/launcher3/compat/AppWidgetManagerCompatVO.java b/src/com/android/launcher3/compat/AppWidgetManagerCompatVO.java
index b7b0563..11ec333 100644
--- a/src/com/android/launcher3/compat/AppWidgetManagerCompatVO.java
+++ b/src/com/android/launcher3/compat/AppWidgetManagerCompatVO.java
@@ -19,14 +19,14 @@
 import android.appwidget.AppWidgetProviderInfo;
 import android.content.Context;
 
+import androidx.annotation.Nullable;
+
 import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.util.PackageUserKey;
 
 import java.util.Collections;
 import java.util.List;
 
-import androidx.annotation.Nullable;
-
 class AppWidgetManagerCompatVO extends AppWidgetManagerCompatVL {
 
     AppWidgetManagerCompatVO(Context context) {
diff --git a/src/com/android/launcher3/config/BaseFlags.java b/src/com/android/launcher3/config/BaseFlags.java
index 1523278..46243f7 100644
--- a/src/com/android/launcher3/config/BaseFlags.java
+++ b/src/com/android/launcher3/config/BaseFlags.java
@@ -23,11 +23,11 @@
 
 import androidx.annotation.GuardedBy;
 import androidx.annotation.Keep;
-
 import androidx.annotation.VisibleForTesting;
-import com.android.launcher3.Utilities;
 
+import com.android.launcher3.Utilities;
 import com.android.launcher3.uioverrides.TogglableFlag;
+
 import java.util.ArrayList;
 import java.util.List;
 import java.util.SortedMap;
@@ -74,9 +74,6 @@
     //Feature flag to enable pulling down navigation shade from workspace.
     public static final boolean PULL_DOWN_STATUS_BAR = true;
 
-    // When true, custom widgets are loaded using CustomWidgetParser.
-    public static final boolean ENABLE_CUSTOM_WIDGETS = false;
-
     // Features to control Launcher3Go behavior
     public static final boolean GO_DISABLE_WIDGETS = false;
 
diff --git a/src/com/android/launcher3/widget/custom/CustomWidgetManager.java b/src/com/android/launcher3/widget/custom/CustomWidgetManager.java
new file mode 100644
index 0000000..cf3e26d
--- /dev/null
+++ b/src/com/android/launcher3/widget/custom/CustomWidgetManager.java
@@ -0,0 +1,163 @@
+/*
+ * Copyright (C) 2019 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.widget.custom;
+
+import static com.android.launcher3.LauncherAppWidgetProviderInfo.CLS_CUSTOM_WIDGET_PREFIX;
+
+import android.appwidget.AppWidgetManager;
+import android.appwidget.AppWidgetProviderInfo;
+import android.content.ComponentName;
+import android.content.Context;
+import android.os.Parcel;
+import android.os.Process;
+import android.util.SparseArray;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import com.android.launcher3.LauncherAppWidgetInfo;
+import com.android.launcher3.LauncherAppWidgetProviderInfo;
+import com.android.launcher3.uioverrides.plugins.PluginManagerWrapper;
+import com.android.launcher3.util.MainThreadInitializedObject;
+import com.android.launcher3.util.PackageUserKey;
+import com.android.launcher3.widget.LauncherAppWidgetHostView;
+import com.android.systemui.plugins.CustomWidgetPlugin;
+import com.android.systemui.plugins.PluginListener;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Consumer;
+
+/**
+ * CustomWidgetManager handles custom widgets implemented as a plugin.
+ */
+public class CustomWidgetManager implements PluginListener<CustomWidgetPlugin> {
+
+    public static final MainThreadInitializedObject<CustomWidgetManager> INSTANCE =
+            new MainThreadInitializedObject<>(CustomWidgetManager::new);
+
+    private final List<CustomWidgetPlugin> mPlugins;
+    private final List<CustomAppWidgetProviderInfo> mCustomWidgets;
+    private final SparseArray<ComponentName> mWidgetsIdMap;
+    private Consumer<PackageUserKey> mWidgetRefreshCallback;
+
+    private CustomWidgetManager(Context context) {
+        mPlugins = new ArrayList<>();
+        mCustomWidgets = new ArrayList<>();
+        mWidgetsIdMap = new SparseArray<>();
+        PluginManagerWrapper.INSTANCE.get(context)
+                .addPluginListener(this, CustomWidgetPlugin.class, true);
+    }
+
+    @Override
+    public void onPluginConnected(CustomWidgetPlugin plugin, Context context) {
+        mPlugins.add(plugin);
+        List<AppWidgetProviderInfo> providers = AppWidgetManager.getInstance(context)
+                .getInstalledProvidersForProfile(Process.myUserHandle());
+        if (providers.isEmpty()) return;
+        Parcel parcel = Parcel.obtain();
+        providers.get(0).writeToParcel(parcel, 0);
+        parcel.setDataPosition(0);
+        CustomAppWidgetProviderInfo info = newInfo(plugin, parcel, context);
+        parcel.recycle();
+        mCustomWidgets.add(info);
+        mWidgetsIdMap.put(plugin.getProviderId(), info.provider);
+        mWidgetRefreshCallback.accept(null);
+    }
+
+    @Override
+    public void onPluginDisconnected(CustomWidgetPlugin plugin) {
+        mPlugins.remove(plugin);
+        mCustomWidgets.remove(getWidgetProvider(plugin.getProviderId()));
+        mWidgetsIdMap.remove(plugin.getProviderId());
+    }
+
+    /**
+     * Inject a callback function to refresh the widgets.
+     */
+    public void setWidgetRefreshCallback(Consumer<PackageUserKey> cb) {
+        mWidgetRefreshCallback = cb;
+    }
+
+    /**
+     * Callback method to inform a plugin it's corresponding widget has been created.
+     */
+    public void onViewCreated(LauncherAppWidgetHostView view) {
+        CustomAppWidgetProviderInfo info = (CustomAppWidgetProviderInfo) view.getAppWidgetInfo();
+        CustomWidgetPlugin plugin = findPlugin(info.providerId);
+        if (plugin == null) return;
+        plugin.onViewCreated(view);
+    }
+
+    /**
+     * Returns the list of custom widgets.
+     */
+    @NonNull
+    public List<CustomAppWidgetProviderInfo> getCustomWidgets() {
+        return mCustomWidgets;
+    }
+
+    /**
+     * Returns the widget id for a specific provider.
+     */
+    public int getWidgetIdForCustomProvider(@NonNull ComponentName provider) {
+        int index = mWidgetsIdMap.indexOfValue(provider);
+        if (index >= 0) {
+            return LauncherAppWidgetInfo.CUSTOM_WIDGET_ID - mWidgetsIdMap.keyAt(index);
+        } else {
+            return AppWidgetManager.INVALID_APPWIDGET_ID;
+        }
+    }
+
+    /**
+     * Returns the widget provider in respect to given widget id.
+     */
+    @Nullable
+    public LauncherAppWidgetProviderInfo getWidgetProvider(int widgetId) {
+        ComponentName cn = mWidgetsIdMap.get(LauncherAppWidgetInfo.CUSTOM_WIDGET_ID - widgetId);
+        for (LauncherAppWidgetProviderInfo info : mCustomWidgets) {
+            if (info.provider.equals(cn)) return info;
+        }
+        return null;
+    }
+
+    private static CustomAppWidgetProviderInfo newInfo(
+            CustomWidgetPlugin plugin, Parcel parcel, Context context) {
+        int providerId = plugin.getProviderId();
+        CustomAppWidgetProviderInfo info = new CustomAppWidgetProviderInfo(
+                parcel, false, providerId);
+        info.provider = new ComponentName(
+                context.getPackageName(), CLS_CUSTOM_WIDGET_PREFIX + providerId);
+
+        info.label = plugin.getLabel();
+        info.icon = plugin.getIcon();
+        info.previewImage = plugin.getPreviewImage();
+        info.resizeMode = plugin.getResizeMode();
+
+        info.spanX = plugin.getSpanX();
+        info.spanY = plugin.getSpanY();
+        info.minSpanX = plugin.getMinSpanX();
+        info.minSpanY = plugin.getMinSpanY();
+        return info;
+    }
+
+    @Nullable
+    private CustomWidgetPlugin findPlugin(int providerId) {
+        return mPlugins.stream().filter((p) -> p.getProviderId() == providerId).findFirst()
+                .orElse(null);
+    }
+}
diff --git a/src/com/android/launcher3/widget/custom/CustomWidgetParser.java b/src/com/android/launcher3/widget/custom/CustomWidgetParser.java
deleted file mode 100644
index 00720c4..0000000
--- a/src/com/android/launcher3/widget/custom/CustomWidgetParser.java
+++ /dev/null
@@ -1,142 +0,0 @@
-/*
- * Copyright (C) 2017 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.widget.custom;
-
-import android.appwidget.AppWidgetManager;
-import android.appwidget.AppWidgetProviderInfo;
-import android.content.ComponentName;
-import android.content.Context;
-import android.content.res.TypedArray;
-import android.content.res.XmlResourceParser;
-import android.os.Parcel;
-import android.os.Process;
-import android.util.SparseArray;
-import android.util.Xml;
-
-import com.android.launcher3.LauncherAppWidgetInfo;
-import com.android.launcher3.LauncherAppWidgetProviderInfo;
-import com.android.launcher3.R;
-
-import org.xmlpull.v1.XmlPullParser;
-import org.xmlpull.v1.XmlPullParserException;
-
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.List;
-
-import static com.android.launcher3.LauncherAppWidgetProviderInfo.CLS_CUSTOM_WIDGET_PREFIX;
-
-/**
- * Utility class to parse {@ink CustomAppWidgetProviderInfo} definitions from xml
- */
-public class CustomWidgetParser {
-
-    private static List<LauncherAppWidgetProviderInfo> sCustomWidgets;
-    private static SparseArray<ComponentName> sWidgetsIdMap;
-
-    public static List<LauncherAppWidgetProviderInfo> getCustomWidgets(Context context) {
-        if (sCustomWidgets == null) {
-            // Synchronization not needed as it it safe to load multiple times
-            parseCustomWidgets(context);
-        }
-
-        return sCustomWidgets;
-    }
-
-    public static int getWidgetIdForCustomProvider(Context context, ComponentName provider) {
-        if (sWidgetsIdMap == null) {
-            parseCustomWidgets(context);
-        }
-        int index = sWidgetsIdMap.indexOfValue(provider);
-        if (index >= 0) {
-            return LauncherAppWidgetInfo.CUSTOM_WIDGET_ID - sWidgetsIdMap.keyAt(index);
-        } else {
-            return AppWidgetManager.INVALID_APPWIDGET_ID;
-        }
-    }
-
-    public static LauncherAppWidgetProviderInfo getWidgetProvider(Context context, int widgetId) {
-        if (sWidgetsIdMap == null || sCustomWidgets == null) {
-            parseCustomWidgets(context);
-        }
-        ComponentName cn = sWidgetsIdMap.get(LauncherAppWidgetInfo.CUSTOM_WIDGET_ID - widgetId);
-        for (LauncherAppWidgetProviderInfo info : sCustomWidgets) {
-            if (info.provider.equals(cn)) {
-                return info;
-            }
-        }
-        return null;
-    }
-
-    private static void parseCustomWidgets(Context context) {
-        ArrayList<LauncherAppWidgetProviderInfo> widgets = new ArrayList<>();
-        SparseArray<ComponentName> idMap = new SparseArray<>();
-
-        List<AppWidgetProviderInfo> providers = AppWidgetManager.getInstance(context)
-                .getInstalledProvidersForProfile(Process.myUserHandle());
-        if (providers.isEmpty()) {
-            sCustomWidgets = widgets;
-            sWidgetsIdMap = idMap;
-            return;
-        }
-
-        Parcel parcel = Parcel.obtain();
-        providers.get(0).writeToParcel(parcel, 0);
-
-        try (XmlResourceParser parser = context.getResources().getXml(R.xml.custom_widgets)) {
-            final int depth = parser.getDepth();
-            int type;
-
-            while (((type = parser.next()) != XmlPullParser.END_TAG ||
-                    parser.getDepth() > depth) && type != XmlPullParser.END_DOCUMENT) {
-                if ((type == XmlPullParser.START_TAG) && "widget".equals(parser.getName())) {
-                    TypedArray a = context.obtainStyledAttributes(
-                            Xml.asAttributeSet(parser), R.styleable.CustomAppWidgetProviderInfo);
-
-                    parcel.setDataPosition(0);
-                    CustomAppWidgetProviderInfo info = newInfo(a, parcel, context);
-                    widgets.add(info);
-                    a.recycle();
-
-                    idMap.put(info.providerId, info.provider);
-                }
-            }
-        } catch (IOException | XmlPullParserException e) {
-            throw new RuntimeException(e);
-        }
-        parcel.recycle();
-        sCustomWidgets = widgets;
-        sWidgetsIdMap = idMap;
-    }
-
-    private static CustomAppWidgetProviderInfo newInfo(TypedArray a, Parcel parcel, Context context) {
-        int providerId = a.getInt(R.styleable.CustomAppWidgetProviderInfo_providerId, 0);
-        CustomAppWidgetProviderInfo info = new CustomAppWidgetProviderInfo(parcel, false, providerId);
-        info.provider = new ComponentName(context.getPackageName(), CLS_CUSTOM_WIDGET_PREFIX + providerId);
-
-        info.label = a.getString(R.styleable.CustomAppWidgetProviderInfo_android_label);
-        info.initialLayout = a.getResourceId(R.styleable.CustomAppWidgetProviderInfo_android_initialLayout, 0);
-        info.icon = a.getResourceId(R.styleable.CustomAppWidgetProviderInfo_android_icon, 0);
-        info.previewImage = a.getResourceId(R.styleable.CustomAppWidgetProviderInfo_android_previewImage, 0);
-        info.resizeMode = a.getInt(R.styleable.CustomAppWidgetProviderInfo_android_resizeMode, 0);
-
-        info.spanX = a.getInt(R.styleable.CustomAppWidgetProviderInfo_numColumns, 1);
-        info.spanY = a.getInt(R.styleable.CustomAppWidgetProviderInfo_numRows, 1);
-        info.minSpanX = a.getInt(R.styleable.CustomAppWidgetProviderInfo_numMinColumns, 1);
-        info.minSpanY = a.getInt(R.styleable.CustomAppWidgetProviderInfo_numMinRows, 1);
-        return info;
-    }
-}
diff --git a/src_plugins/com/android/systemui/plugins/CustomWidgetPlugin.java b/src_plugins/com/android/systemui/plugins/CustomWidgetPlugin.java
new file mode 100644
index 0000000..77ad7ea
--- /dev/null
+++ b/src_plugins/com/android/systemui/plugins/CustomWidgetPlugin.java
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2019 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.systemui.plugins;
+
+import android.appwidget.AppWidgetHostView;
+
+import com.android.systemui.plugins.annotations.ProvidesInterface;
+
+/**
+ * Implement this plugin interface to add a custom widget.
+ */
+@ProvidesInterface(action = CustomWidgetPlugin.ACTION, version = CustomWidgetPlugin.VERSION)
+public interface CustomWidgetPlugin extends Plugin {
+
+    String ACTION = "com.android.systemui.action.PLUGIN_CUSTOM_WIDGET";
+    int VERSION = 1;
+
+    /**
+     * An unique identifier for this widget. Must be a non-negative integer.
+     */
+    int getProviderId();
+
+    /**
+     * The label to display to the user in the AppWidget picker.
+     */
+    String getLabel();
+
+    /**
+     * A preview of what the AppWidget will look like after it's configured.
+     * If not supplied, the AppWidget's icon will be used.
+     */
+    int getPreviewImage();
+
+    /**
+     * The icon to display for this AppWidget in the AppWidget picker. If not supplied in the
+     * xml, the application icon will be used.
+     */
+    int getIcon();
+
+    /**
+     * The default width of the widget when added to a host, in dp. The widget will get
+     * at least this width, and will often be given more, depending on the host.
+     */
+    int getSpanX();
+
+    /**
+     * The default height of the widget when added to a host, in dp. The widget will get
+     * at least this height, and will often be given more, depending on the host.
+     */
+    int getSpanY();
+
+    /**
+     * Minimum width (in dp) which the widget can be resized to. This field has no effect if it
+     * is greater than minWidth or if horizontal resizing isn't enabled.
+     */
+    int getMinSpanX();
+
+    /**
+     * Minimum height (in dp) which the widget can be resized to. This field has no effect if it
+     * is greater than minHeight or if vertical resizing isn't enabled.
+     */
+    int getMinSpanY();
+
+    /**
+     * The rules by which a widget can be resized.
+     */
+    int getResizeMode();
+
+    /**
+     * Notify the plugin that container of the widget has been rendered, where the custom widget
+     * can be attached to.
+     */
+    void onViewCreated(AppWidgetHostView parent);
+}