Keeping task list stable across multiple task switches
Change-Id: I3b334a8c8fb13ad54bc19e782cae016fe3c78ff6
diff --git a/quickstep/src/com/android/quickstep/RecentTasksList.java b/quickstep/src/com/android/quickstep/RecentTasksList.java
index e1b4474..cedd952 100644
--- a/quickstep/src/com/android/quickstep/RecentTasksList.java
+++ b/quickstep/src/com/android/quickstep/RecentTasksList.java
@@ -44,6 +44,7 @@
private final KeyguardManagerCompat mKeyguardManager;
private final MainThreadExecutor mMainThreadExecutor;
private final BackgroundExecutor mBgThreadExecutor;
+ private final TaskListStabilizer mStabilizer = new TaskListStabilizer();
// The list change id, increments as the task list changes in the system
private int mChangeId;
@@ -83,7 +84,7 @@
final int requestLoadId = mChangeId;
Runnable resultCallback = callback == null
? () -> { }
- : () -> callback.accept(mTasks);
+ : () -> callback.accept(mStabilizer.reorder(mTasks));
if (mLastLoadedId == mChangeId && (!mLastLoadHadKeysOnly || loadKeysOnly)) {
// The list is up to date, callback with the same list
diff --git a/quickstep/src/com/android/quickstep/TaskListStabilizer.java b/quickstep/src/com/android/quickstep/TaskListStabilizer.java
new file mode 100644
index 0000000..0d23973
--- /dev/null
+++ b/quickstep/src/com/android/quickstep/TaskListStabilizer.java
@@ -0,0 +1,95 @@
+/*
+ * 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.quickstep;
+
+import static com.android.launcher3.config.FeatureFlags.ENABLE_TASK_STABILIZER;
+
+import android.os.SystemClock;
+import android.util.SparseArray;
+
+import com.android.launcher3.util.IntArray;
+import com.android.launcher3.util.IntSet;
+import com.android.systemui.shared.recents.model.Task;
+
+import java.util.ArrayList;
+
+public class TaskListStabilizer {
+
+ private static final long TASK_CACHE_TIMEOUT_MS = 5000;
+
+ private final SparseArray<Task> mTempMap = new SparseArray<>();
+ private final IntArray mTempArray = new IntArray();
+ private final IntSet mTempSet = new IntSet();
+
+ private final IntArray mLastStableOrder = new IntArray();
+ private final IntSet mLastSet = new IntSet();
+ private final IntArray mLastUnstableOrder = new IntArray();
+
+ private long mLastReorderTime;
+
+ public ArrayList<Task> reorder(ArrayList<Task> tasks) {
+ if (!ENABLE_TASK_STABILIZER.get()) {
+ return tasks;
+ }
+
+ // Create task id array
+ int count = tasks.size();
+ mTempArray.clear();
+ mTempSet.clear();
+ mTempMap.clear();
+
+ for (int i = 0; i < count; i++) {
+ Task t = tasks.get(i);
+ mTempMap.put(t.key.id, t);
+
+ mTempSet.add(t.key.id);
+ mTempArray.add(t.key.id);
+ }
+
+ if (mLastSet.equals(mTempSet) && isStabilizationQuickEnough()) {
+ if (mLastStableOrder.equals(mTempArray)) {
+ // Everything is same
+ return tasks;
+ }
+
+ if (!mLastUnstableOrder.equals(mTempArray)) {
+ // Fast reordering, record the current time.
+ mLastUnstableOrder.copyFrom(mTempArray);
+ mLastReorderTime = SystemClock.uptimeMillis();
+ }
+
+ // Reorder the tasks based on the last stable order.
+ ArrayList<Task> sorted = new ArrayList<>(count);
+ for (int i = 0; i < count; i++) {
+ sorted.add(mTempMap.get(mLastStableOrder.get(i)));
+ }
+ return sorted;
+ }
+
+ // Cache the data
+ mLastStableOrder.copyFrom(mTempArray);
+ mLastUnstableOrder.copyFrom(mTempArray);
+ mLastSet.copyFrom(mTempSet);
+
+ mLastReorderTime = SystemClock.uptimeMillis();
+
+ return tasks;
+ }
+
+ private boolean isStabilizationQuickEnough() {
+ return (SystemClock.uptimeMillis() - mLastReorderTime) < TASK_CACHE_TIMEOUT_MS;
+ }
+}
diff --git a/quickstep/src/com/android/quickstep/views/RecentsView.java b/quickstep/src/com/android/quickstep/views/RecentsView.java
index 7842fa4..1cd1ab9 100644
--- a/quickstep/src/com/android/quickstep/views/RecentsView.java
+++ b/quickstep/src/com/android/quickstep/views/RecentsView.java
@@ -749,7 +749,8 @@
setRunningTaskIconScaledDown(runningTaskIconScaledDown);
setRunningTaskHidden(runningTaskTileHidden);
- setCurrentPage(0);
+ TaskView tv = getRunningTaskView();
+ setCurrentPage(tv == null ? 0 : indexOfChild(tv));
// Load the tasks (if the loading is already
mTaskListChangeId = mModel.getTasks(this::applyLoadPlan);
diff --git a/src/com/android/launcher3/config/BaseFlags.java b/src/com/android/launcher3/config/BaseFlags.java
index 23ad912..3f420fa 100644
--- a/src/com/android/launcher3/config/BaseFlags.java
+++ b/src/com/android/launcher3/config/BaseFlags.java
@@ -95,6 +95,9 @@
public static final TogglableFlag APPLY_CONFIG_AT_RUNTIME = new TogglableFlag(
"APPLY_CONFIG_AT_RUNTIME", false, "Apply display changes dynamically");
+ public static final TogglableFlag ENABLE_TASK_STABILIZER = new TogglableFlag(
+ "ENABLE_TASK_STABILIZER", true, "Stable task list across fast task switches");
+
public static void initialize(Context context) {
// Avoid the disk read for user builds
if (Utilities.IS_DEBUG_DEVICE) {
diff --git a/src/com/android/launcher3/util/IntArray.java b/src/com/android/launcher3/util/IntArray.java
index b2fb32a..d2a551f 100644
--- a/src/com/android/launcher3/util/IntArray.java
+++ b/src/com/android/launcher3/util/IntArray.java
@@ -100,6 +100,14 @@
}
/**
+ * Sets the array to be same as {@param other}
+ */
+ public void copyFrom(IntArray other) {
+ clear();
+ addAll(other);
+ }
+
+ /**
* Ensures capacity to append at least <code>count</code> values.
*/
private void ensureCapacity(int count) {
@@ -127,6 +135,25 @@
return wrap(toArray());
}
+ @Override
+ public boolean equals(Object obj) {
+ if (obj == this) {
+ return true;
+ }
+ if (obj instanceof IntArray) {
+ IntArray arr = (IntArray) obj;
+ if (mSize == arr.mSize) {
+ for (int i = 0; i < mSize; i++) {
+ if (arr.mValues[i] != mValues[i]) {
+ return false;
+ }
+ }
+ return true;
+ }
+ }
+ return false;
+ }
+
/**
* Returns the value at the specified position in this array.
*/
diff --git a/src/com/android/launcher3/util/IntSet.java b/src/com/android/launcher3/util/IntSet.java
index 2459fad..851f129 100644
--- a/src/com/android/launcher3/util/IntSet.java
+++ b/src/com/android/launcher3/util/IntSet.java
@@ -49,10 +49,29 @@
return mArray.size();
}
+ public void clear() {
+ mArray.clear();
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (obj == this) {
+ return true;
+ }
+ return (obj instanceof IntSet) && ((IntSet) obj).mArray.equals(mArray);
+ }
+
public IntArray getArray() {
return mArray;
}
+ /**
+ * Sets this set to be same as {@param other}
+ */
+ public void copyFrom(IntSet other) {
+ mArray.copyFrom(other.mArray);
+ }
+
public static IntSet wrap(IntArray array) {
IntSet set = new IntSet();
set.mArray.addAll(array);