Filter shortcuts down to 4 if there are more.

- We take the first 4 in sorted order, except we remove up to 2
  static shortcuts to make room for dynamic ones if they exist.
- Added ShortcutFilterTest with testSortAndFilterShortcuts().
  This asserts that the filtered list is sorted and has the
  expected number of static and dynamic shortcuts based on
  inputs with various amounts of each.

Bug: 28980830
Change-Id: I832b6b21144f17c74bb8b90a840d6620e99911b8

2 files changed, 101 insertions, 29 deletions

diff --git a/src/com/android/launcher3/shortcuts/DeepShortcutsContainer.java b/src/com/android/launcher3/shortcuts/DeepShortcutsContainer.java
index 7aa212321..7b24c2676 100644
--- a/src/com/android/launcher3/shortcuts/DeepShortcutsContainer.java
+++ b/src/com/android/launcher3/shortcuts/DeepShortcutsContainer.java
@@ -69,7 +69,6 @@ import com.android.launcher3.userevent.nano.LauncherLogProto;
 import com.android.launcher3.userevent.nano.LauncherLogProto.Target;
 
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.List;
 
 /**
@@ -110,29 +109,9 @@ public class DeepShortcutsContainer extends LinearLayout implements View.OnLongC
     private boolean mIsRtl;
     private int mArrowHorizontalOffset;
 
-    /**
-     * Sorts shortcuts in rank order, with manifest shortcuts coming before dynamic shortcuts.
-     */
-    private static final Comparator<ShortcutInfoCompat> sShortcutsComparator
-            = new Comparator<ShortcutInfoCompat>() {
-        @Override
-        public int compare(ShortcutInfoCompat a, ShortcutInfoCompat b) {
-            if (a.isDeclaredInManifest() && !b.isDeclaredInManifest()) {
-                return -1;
-            }
-            if (!a.isDeclaredInManifest() && b.isDeclaredInManifest()) {
-                return 1;
-            }
-            return Integer.compare(a.getRank(), b.getRank());
-        }
-    };
-
-    private static final Comparator<ShortcutInfoCompat> sShortcutsComparatorReversed
-            = Collections.reverseOrder(sShortcutsComparator);
-
     public DeepShortcutsContainer(Context context, AttributeSet attrs, int defStyleAttr) {
         super(context, attrs, defStyleAttr);
-        mLauncher = (Launcher) context;
+        mLauncher = Launcher.getLauncher(context);
         mDeepShortcutsManager = LauncherAppState.getInstance().getShortcutManager();
 
         mDragDeadzone = ViewConfiguration.get(context).getScaledTouchSlop();
@@ -154,10 +133,11 @@ public class DeepShortcutsContainer extends LinearLayout implements View.OnLongC
         // Add dummy views first, and populate with real shortcut info when ready.
         final int spacing = getResources().getDimensionPixelSize(R.dimen.deep_shortcuts_spacing);
         final LayoutInflater inflater = mLauncher.getLayoutInflater();
-        for (int i = 0; i < ids.size(); i++) {
+        int numShortcuts = Math.min(ids.size(), ShortcutFilter.MAX_SHORTCUTS);
+        for (int i = 0; i < numShortcuts; i++) {
             final DeepShortcutView shortcut =
                     (DeepShortcutView) inflater.inflate(R.layout.deep_shortcut, this, false);
-            if (i < ids.size() - 1) {
+            if (i < numShortcuts - 1) {
                 ((LayoutParams) shortcut.getLayoutParams()).bottomMargin = spacing;
             }
             shortcut.getBubbleText().setAccessibilityDelegate(mAccessibilityDelegate);
@@ -190,12 +170,12 @@ public class DeepShortcutsContainer extends LinearLayout implements View.OnLongC
         new Handler(workerLooper).postAtFrontOfQueue(new Runnable() {
             @Override
             public void run() {
-                final List<ShortcutInfoCompat> shortcuts = mDeepShortcutsManager
-                        .queryForShortcutsContainer(activity, ids, user);
+                final List<ShortcutInfoCompat> shortcuts = ShortcutFilter.sortAndFilterShortcuts(
+                        mDeepShortcutsManager.queryForShortcutsContainer(activity, ids, user));
                 // We want the lowest rank to be closest to the user's finger.
-                final Comparator<ShortcutInfoCompat> shortcutsComparator = mIsAboveIcon ?
-                        sShortcutsComparatorReversed : sShortcutsComparator;
-                Collections.sort(shortcuts, shortcutsComparator);
+                if (mIsAboveIcon) {
+                    Collections.reverse(shortcuts);
+                }
                 for (int i = 0; i < shortcuts.size(); i++) {
                     final ShortcutInfoCompat shortcut = shortcuts.get(i);
                     final ShortcutInfo launcherShortcutInfo =
diff --git a/src/com/android/launcher3/shortcuts/ShortcutFilter.java b/src/com/android/launcher3/shortcuts/ShortcutFilter.java
new file mode 100644
index 000000000..ec6881730
--- /dev/null
+++ b/src/com/android/launcher3/shortcuts/ShortcutFilter.java
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2016 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.shortcuts;
+
+import android.support.annotation.VisibleForTesting;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * Sorts and filters shortcuts.
+ */
+public class ShortcutFilter {
+
+    public static final int MAX_SHORTCUTS = 4;
+    @VisibleForTesting static final int NUM_DYNAMIC = 2;
+
+    /**
+     * Sorts shortcuts in rank order, with manifest shortcuts coming before dynamic shortcuts.
+     */
+    private static final Comparator<ShortcutInfoCompat> RANK_COMPARATOR
+            = new Comparator<ShortcutInfoCompat>() {
+        @Override
+        public int compare(ShortcutInfoCompat a, ShortcutInfoCompat b) {
+            if (a.isDeclaredInManifest() && !b.isDeclaredInManifest()) {
+                return -1;
+            }
+            if (!a.isDeclaredInManifest() && b.isDeclaredInManifest()) {
+                return 1;
+            }
+            return Integer.compare(a.getRank(), b.getRank());
+        }
+    };
+
+    /**
+     * Filters the shortcuts so that only MAX_SHORTCUTS or fewer shortcuts are retained.
+     * We want the filter to include both static and dynamic shortcuts, so we always
+     * include NUM_DYNAMIC dynamic shortcuts, if at least that many are present.
+     *
+     * @return a subset of shortcuts, in sorted order, with size <= MAX_SHORTCUTS.
+     */
+    public static List<ShortcutInfoCompat> sortAndFilterShortcuts(
+            List<ShortcutInfoCompat> shortcuts) {
+        Collections.sort(shortcuts, RANK_COMPARATOR);
+        if (shortcuts.size() <= MAX_SHORTCUTS) {
+            return shortcuts;
+        }
+
+        // The list of shortcuts is now sorted with static shortcuts followed by dynamic
+        // shortcuts. We want to preserve this order, but only keep MAX_SHORTCUTS.
+        List<ShortcutInfoCompat> filteredShortcuts = new ArrayList<>(MAX_SHORTCUTS);
+        int numDynamic = 0;
+        int size = shortcuts.size();
+        for (int i = 0; i < size; i++) {
+            ShortcutInfoCompat shortcut = shortcuts.get(i);
+            int filteredSize = filteredShortcuts.size();
+            if (filteredSize < MAX_SHORTCUTS) {
+                // Always add the first MAX_SHORTCUTS to the filtered list.
+                filteredShortcuts.add(shortcut);
+                if (shortcut.isDynamic()) {
+                    numDynamic++;
+                }
+                continue;
+            }
+            // At this point, we have MAX_SHORTCUTS already, but they may all be static.
+            // If there are dynamic shortcuts, remove static shortcuts to add them.
+            if (shortcut.isDynamic() && numDynamic < NUM_DYNAMIC) {
+                numDynamic++;
+                int lastStaticIndex = filteredSize - numDynamic;
+                filteredShortcuts.remove(lastStaticIndex);
+                filteredShortcuts.add(shortcut);
+            }
+        }
+        return filteredShortcuts;
+    }
+}