Workaround for not showing previous tasks when time is set.

package com.android.systemui.recents;

import android.app.Activity;

import android.app.ActivityManager;

import android.app.ActivityOptions;

import android.app.TaskStackBuilder;

import android.content.BroadcastReceiver;

import java.io.FileDescriptor;

import java.io.PrintWriter;

import java.util.List;

/**

 * The main Recents activity that is started from RecentsComponent.

     */

    final BroadcastReceiver mSystemBroadcastReceiver = new BroadcastReceiver() {

        @Override

        public void onReceive(Context context, Intent intent) {

        public void onReceive(Context ctx, Intent intent) {

            String action = intent.getAction();

            if (action.equals(Intent.ACTION_SCREEN_OFF)) {

                // When the screen turns off, dismiss Recents to Home

                dismissRecentsToHomeIfVisible(false);

            } else if (action.equals(Intent.ACTION_TIME_CHANGED)) {

                // For the time being, if the time changes, then invalidate the

                // last-stack-active-time, this ensures that we will just show the last N tasks

                // the next time that Recents loads, but prevents really old tasks from showing

                // up if the task time is set forward.

                Prefs.putLong(RecentsActivity.this, Prefs.Key.OVERVIEW_LAST_STACK_TASK_ACTIVE_TIME,

                        0);

                // If the time shifts but the currentTime >= lastStackActiveTime, then that boundary

                // is still valid.  Otherwise, we need to reset the lastStackactiveTime to the

                // currentTime and remove the old tasks in between which would not be previously

                // visible, but currently would be in the new currentTime

                long oldLastStackActiveTime = Prefs.getLong(RecentsActivity.this,

                        Prefs.Key.OVERVIEW_LAST_STACK_TASK_ACTIVE_TIME, -1);

                if (oldLastStackActiveTime != -1) {

                    long currentTime = System.currentTimeMillis();

                    if (currentTime < oldLastStackActiveTime) {

                        // We are only removing tasks that are between the new current time

                        // and the old last stack active time, they were not visible and in the

                        // TaskStack so we don't need to remove any associated TaskViews but we do

                        // need to load the task id's from the system

                        RecentsTaskLoadPlan loadPlan = Recents.getTaskLoader().createLoadPlan(ctx);

                        loadPlan.preloadRawTasks(false /* includeFrontMostExcludedTask */);

                        List<ActivityManager.RecentTaskInfo> tasks = loadPlan.getRawTasks();

                        for (int i = tasks.size() - 1; i >= 0; i--) {

                            ActivityManager.RecentTaskInfo task = tasks.get(i);

                            if (currentTime <= task.lastActiveTime && task.lastActiveTime <

                                    oldLastStackActiveTime) {

                                Recents.getSystemServices().removeTask(task.persistentId);

                            }

                        }

                        Prefs.putLong(RecentsActivity.this,

                                Prefs.Key.OVERVIEW_LAST_STACK_TASK_ACTIVE_TIME, currentTime);

                    }

                }

            }

        }

    };

        return mStack;

    }

    /**

     * Returns the raw list of recent tasks.

     */

    public List<ActivityManager.RecentTaskInfo> getRawTasks() {

        return mRawTasks;

    }

    /** Returns whether there are any tasks in any stacks. */

    public boolean hasTasks() {

        if (mStack != null) {