plugin for user event logging

Bug: 140243695
Change-Id: If9c620aa10334b26ad9b489d6544201d38439fea

src/com/android/launcher3/logging/UserEventDispatcher.java

@@ -427,10 +427,16 @@ public class UserEventDispatcher implements ResourceBasedOverride {
         mAppOrTaskLaunch = false;
         ev.elapsedContainerMillis = SystemClock.uptimeMillis() - mElapsedContainerMillis;
         ev.elapsedSessionMillis = SystemClock.uptimeMillis() - mElapsedSessionMillis;
-
         if (!IS_VERBOSE) {
             return;
         }
+        Log.d(TAG, generateLog(ev));
+    }
+
+    /**
+     * Returns a human-readable log for given user event.
+     */
+    public static String generateLog(LauncherEvent ev) {
         String log = "\n-----------------------------------------------------"
                 + "\naction:" + LoggerUtils.getActionStr(ev.action);
         if (ev.srcTarget != null && ev.srcTarget.length > 0) {
@@ -445,8 +451,7 @@ public class UserEventDispatcher implements ResourceBasedOverride {
                 ev.elapsedSessionMillis,
                 ev.actionDurationMillis);
         log += "\n\n";
-        Log.d(TAG, log);
-        return;
+        return log;
     }
 
     private static String getTargetsStr(Target[] targets) {

src_plugins/com/android/systemui/plugins/UserEventPlugin.java

@@ -0,0 +1,34 @@
+/*
+ * 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 com.android.systemui.plugins.annotations.ProvidesInterface;
+
+/**
+ * Implement this plugin interface to access user event log on the device for prototype purpose.
+ * NOTE: plugin is for internal prototype only and is not visible in production environment.
+ */
+@ProvidesInterface(action = UserEventPlugin.ACTION, version = UserEventPlugin.VERSION)
+public interface UserEventPlugin extends Plugin {
+    String ACTION = "com.android.launcher3.action.PLUGIN_USER_EVENT_LOG";
+    int VERSION = 1;
+
+    /**
+     * Callback to be triggered whenever an user event occurs.
+     */
+    void onUserEvent(Object event);
+}