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Commit 6f9dbcb7 authored by Jorim Jaggi's avatar Jorim Jaggi
Browse files

Implement new thumbnail loading strategy 

- By default, we load only the reduced resolution screenshots.
- As soon as the user stops scrolling fast, we also start loading
full resolution screenshots.
- We prefetch reduced resolution screenshots when scrolling from
back to front, as the other direction is automatically prefetched
because the thumbnails aren't immediately visible.

Test: Open many apps, adb restart, scroll fast and slow in recents
Test: runtest systemui -c com.android.systemui.recents.model.HighResThumbnailLoaderTest
Bug: 34829962
Change-Id: I7f7a9842eb28a09a18573426fa9677cee2877124
parent 35e3f53a

packages/SystemUI/res/values/dimens.xml

+4 −0
Original line number Diff line number Diff line
@@ -726,6 +726,10 @@ 
    <!-- The alpha to apply to the recents row when it doesn't have focus -->

    <item name="recents_recents_row_dim_alpha" format="float" type="dimen">0.5</item>



    <!-- The speed in dp/s at which the user needs to be scrolling in recents such that we start

         loading full resolution screenshots. -->

    <dimen name="recents_fast_fling_velocity">600dp</dimen>



    <!-- The size of the PIP drag-to-dismiss target. -->

    <dimen name="pip_dismiss_target_size">48dp</dimen>

packages/SystemUI/src/com/android/systemui/recents/Recents.java

+3 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ import android.hardware.display.DisplayManager; 
import android.os.Build;

import android.os.Handler;

import android.os.IBinder;

import android.os.Looper;

import android.os.RemoteException;

import android.os.SystemProperties;

import android.os.UserHandle;
@@ -59,6 +60,7 @@ import com.android.systemui.recents.events.component.ScreenPinningRequestEvent; 
import com.android.systemui.recents.events.component.ShowUserToastEvent;

import com.android.systemui.recents.events.ui.RecentsDrawnEvent;

import com.android.systemui.recents.misc.SystemServicesProxy;

import com.android.systemui.recents.model.HighResThumbnailLoader;

import com.android.systemui.recents.model.RecentsTaskLoader;

import com.android.systemui.stackdivider.Divider;

import com.android.systemui.statusbar.CommandQueue;
@@ -184,6 +186,7 @@ public class Recents extends SystemUI 
        return sTaskLoader;

    }





    public static SystemServicesProxy getSystemServices() {

        return sSystemServicesProxy;

    }

packages/SystemUI/src/com/android/systemui/recents/RecentsActivity.java

+3 −0
Original line number Diff line number Diff line
@@ -375,6 +375,8 @@ public class RecentsActivity extends Activity implements ViewTreeObserver.OnPreD 


        // Notify of the next draw

        mRecentsView.getViewTreeObserver().addOnPreDrawListener(mRecentsDrawnEventListener);



        Recents.getTaskLoader().getHighResThumbnailLoader().setVisible(true);

    }



    @Override
@@ -529,6 +531,7 @@ public class RecentsActivity extends Activity implements ViewTreeObserver.OnPreD 
        mReceivedNewIntent = false;

        EventBus.getDefault().send(new RecentsVisibilityChangedEvent(this, false));

        MetricsLogger.hidden(this, MetricsEvent.OVERVIEW_ACTIVITY);

        Recents.getTaskLoader().getHighResThumbnailLoader().setVisible(false);



        if (!isChangingConfigurations()) {

            // Workaround for b/22542869, if the RecentsActivity is started again, but without going

packages/SystemUI/src/com/android/systemui/recents/misc/SystemServicesProxy.java

+3 −3
Original line number Diff line number Diff line
@@ -637,7 +637,7 @@ public class SystemServicesProxy { 
    }



    /** Returns the top task thumbnail for the given task id */

    public ThumbnailData getTaskThumbnail(int taskId) {

    public ThumbnailData getTaskThumbnail(int taskId, boolean reduced) {

        if (mAm == null) return null;



        // If we are mocking, then just return a dummy thumbnail
@@ -649,7 +649,7 @@ public class SystemServicesProxy { 
            return thumbnailData;

        }



        ThumbnailData thumbnailData = getThumbnail(taskId);

        ThumbnailData thumbnailData = getThumbnail(taskId, reduced);

        if (thumbnailData.thumbnail != null && !ActivityManager.ENABLE_TASK_SNAPSHOTS) {

            thumbnailData.thumbnail.setHasAlpha(false);

            // We use a dumb heuristic for now, if the thumbnail is purely transparent in the top
@@ -669,7 +669,7 @@ public class SystemServicesProxy { 
    /**

     * Returns a task thumbnail from the activity manager

     */

    public @NonNull ThumbnailData getThumbnail(int taskId) {

    public @NonNull ThumbnailData getThumbnail(int taskId, boolean reducedResolution) {

        if (mAm == null) {

            return new ThumbnailData();

        }

packages/SystemUI/src/com/android/systemui/recents/model/HighResThumbnailLoader.java

0 → 100644
+215 −0
Original line number Diff line number Diff line 
/*

 * 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.systemui.recents.model;



import static android.os.Process.setThreadPriority;



import android.os.Handler;

import android.os.Looper;

import android.os.SystemClock;

import android.util.ArraySet;



import com.android.internal.annotations.GuardedBy;

import com.android.internal.annotations.VisibleForTesting;

import com.android.systemui.recents.misc.SystemServicesProxy;

import com.android.systemui.recents.model.Task.TaskCallbacks;



import java.util.ArrayDeque;

import java.util.ArrayList;



/**

 * Loader class that loads full-resolution thumbnails when appropriate.

 */

public class HighResThumbnailLoader implements TaskCallbacks {



    @GuardedBy("mLoadQueue")

    private final ArrayDeque<Task> mLoadQueue = new ArrayDeque<>();

    @GuardedBy("mLoadQueue")

    private final ArraySet<Task> mLoadingTasks = new ArraySet<>();

    @GuardedBy("mLoadQueue")

    private boolean mLoaderIdling;



    private final ArrayList<Task> mVisibleTasks = new ArrayList<>();

    private final Thread mLoadThread;

    private final Handler mMainThreadHandler;

    private final SystemServicesProxy mSystemServicesProxy;

    private boolean mLoading;

    private boolean mVisible;

    private boolean mFlingingFast;



    public HighResThumbnailLoader(SystemServicesProxy ssp, Looper looper) {

        mMainThreadHandler = new Handler(looper);

        mLoadThread = new Thread(mLoader, "Recents-HighResThumbnailLoader");

        mLoadThread.start();

        mSystemServicesProxy = ssp;

    }



    public void setVisible(boolean visible) {

        mVisible = visible;

        updateLoading();

    }



    public void setFlingingFast(boolean flingingFast) {

        if (mFlingingFast == flingingFast) {

            return;

        }

        mFlingingFast = flingingFast;

        updateLoading();

    }



    @VisibleForTesting

    boolean isLoading() {

        return mLoading;

    }



    private void updateLoading() {

        setLoading(mVisible && !mFlingingFast);

    }



    private void setLoading(boolean loading) {

        if (loading == mLoading) {

            return;

        }

        synchronized (mLoadQueue) {

            mLoading = loading;

            if (!loading) {

                stopLoading();

            } else {

                startLoading();

            }

        }

    }



    @GuardedBy("mLoadQueue")

    private void startLoading() {

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

            Task t = mVisibleTasks.get(i);

            if ((t.thumbnail == null || t.thumbnail.reducedResolution)

                    && !mLoadQueue.contains(t) && !mLoadingTasks.contains(t)) {

                mLoadQueue.add(t);

            }

        }

        mLoadQueue.notifyAll();

    }



    @GuardedBy("mLoadQueue")

    private void stopLoading() {

        mLoadQueue.clear();

        mLoadQueue.notifyAll();

    }



    /**

     * Needs to be called when a task becomes visible. Note that this is different from

     * {@link TaskCallbacks#onTaskDataLoaded} as this method should only be called once when it

     * becomes visible, whereas onTaskDataLoaded can be called multiple times whenever some data

     * has been updated.

     */

    public void onTaskVisible(Task t) {

        t.addCallback(this);

        mVisibleTasks.add(t);

        if ((t.thumbnail == null || t.thumbnail.reducedResolution) && mLoading) {

            synchronized (mLoadQueue) {

                mLoadQueue.add(t);

                mLoadQueue.notifyAll();

            }

        }

    }



    /**

     * Needs to be called when a task becomes visible. See {@link #onTaskVisible} why this is

     * different from {@link TaskCallbacks#onTaskDataUnloaded()}

     */

    public void onTaskInvisible(Task t) {

        t.removeCallback(this);

        mVisibleTasks.remove(t);

        synchronized (mLoadQueue) {

            mLoadQueue.remove(t);

        }

    }



    @VisibleForTesting

    void waitForLoaderIdle() {

        while (true) {

            synchronized (mLoadQueue) {

                if (mLoadQueue.isEmpty() && mLoaderIdling) {

                    return;

                }

            }

            SystemClock.sleep(100);

        }

    }



    @Override

    public void onTaskDataLoaded(Task task, ThumbnailData thumbnailData) {

        if (thumbnailData != null && !thumbnailData.reducedResolution) {

            synchronized (mLoadQueue) {

                mLoadQueue.remove(task);

            }

        }

    }



    @Override

    public void onTaskDataUnloaded() {

    }



    @Override

    public void onTaskStackIdChanged() {

    }



    private final Runnable mLoader = new Runnable() {



        @Override

        public void run() {

            setThreadPriority(android.os.Process.THREAD_PRIORITY_BACKGROUND + 1);

            while (true) {

                Task next = null;

                synchronized (mLoadQueue) {

                    if (!mLoading || mLoadQueue.isEmpty()) {

                        try {

                            mLoaderIdling = true;

                            mLoadQueue.wait();

                            mLoaderIdling = false;

                        } catch (InterruptedException e) {

                            // Don't care.

                        }

                    } else {

                        next = mLoadQueue.poll();

                        if (next != null) {

                            mLoadingTasks.add(next);

                        }

                    }

                }

                if (next != null) {

                    loadTask(next);

                }

            }

        }



        private void loadTask(Task t) {

            ThumbnailData thumbnail = mSystemServicesProxy.getTaskThumbnail(t.key.id,

                    false /* reducedResolution */);

            mMainThreadHandler.post(() -> {

                synchronized (mLoadQueue) {

                    mLoadingTasks.remove(t);

                }

                if (mVisibleTasks.contains(t)) {

                    t.notifyTaskDataLoaded(thumbnail, t.icon);

                }

            });

        }

    };

}