Refactoring language list to use drag-reordering classes

Change-Id: I281bb273a2052743beae656fbb357e46613f8e52
Bug: 993066
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1716959
Commit-Queue: Jenna Himawan <jhimawan@google.com>
Reviewed-by: anthonyvd <anthonyvd@chromium.org>
Reviewed-by: Theresa  <twellington@chromium.org>
Reviewed-by: Matthew Jones <mdjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686225}

chrome/android/java/src/org/chromium/chrome/browser/preferences/PrefServiceBridge.java

@@ -928,6 +928,15 @@ public class PrefServiceBridge {
         nativeMoveAcceptLanguage(languageCode, offset);
     }
 
+    /**
+     * Given an array of language codes, sets the order of the user's accepted languages to match.
+     *
+     * @param codes The new order for the user's accepted languages.
+     */
+    public void setLanguageOrder(String[] codes) {
+        nativeSetLanguageOrder(codes);
+    }
+
     /**
      * @param languageCode A valid language code to check.
      * @return Whether the given language is blocked by the user.
@@ -1171,6 +1180,7 @@ public class PrefServiceBridge {
     private native void nativeGetUserAcceptLanguages(List<String> list);
     private native void nativeUpdateUserAcceptLanguages(String language, boolean add);
     private native void nativeMoveAcceptLanguage(String language, int offset);
+    private native void nativeSetLanguageOrder(String[] codes);
     private native boolean nativeIsBlockedLanguage(String language);
     private native void nativeSetLanguageBlockedState(String language, boolean blocked);
     private native String nativeGetDownloadDefaultDirectory();

chrome/android/java/src/org/chromium/chrome/browser/preferences/languages/AddLanguageFragment.java

@@ -12,6 +12,7 @@ import android.support.v4.app.Fragment;
 import android.support.v7.widget.DividerItemDecoration;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.ViewHolder;
 import android.support.v7.widget.SearchView;
 import android.text.TextUtils;
 import android.view.LayoutInflater;
@@ -51,9 +52,10 @@ public class AddLanguageFragment extends Fragment {
         }
 
         @Override
-        public void onBindViewHolder(LanguageRowViewHolder holder, int position) {
+        public void onBindViewHolder(ViewHolder holder, int position) {
             super.onBindViewHolder(holder, position);
-            holder.setItemClickListener(getItemByPosition(position), mItemClickListener);
+            ((LanguageRowViewHolder) holder)
+                    .setItemClickListener(getItemByPosition(position), mItemClickListener);
         }
 
         /**
@@ -62,7 +64,7 @@ public class AddLanguageFragment extends Fragment {
          */
         private void search(String query) {
             if (TextUtils.isEmpty(query)) {
-                reload(mFullLanguageList);
+                setDisplayedLanguages(mFullLanguageList);
                 return;
             }
 
@@ -76,7 +78,7 @@ public class AddLanguageFragment extends Fragment {
                     results.add(item);
                 }
             }
-            reload(results);
+            setDisplayedLanguages(results);
         }
     }
 
@@ -124,7 +126,7 @@ public class AddLanguageFragment extends Fragment {
         mAdapter = new LanguageSearchListAdapter(activity);
 
         mRecyclerView.setAdapter(mAdapter);
-        mAdapter.reload(mFullLanguageList);
+        mAdapter.setDisplayedLanguages(mFullLanguageList);
         mRecyclerView.getViewTreeObserver().addOnScrollChangedListener(
                 PreferenceUtils.getShowShadowOnScrollListener(
                         mRecyclerView, view.findViewById(R.id.shadow)));
@@ -141,7 +143,7 @@ public class AddLanguageFragment extends Fragment {
 
         mSearchView.setOnCloseListener(() -> {
             mSearch = "";
-            mAdapter.reload(mFullLanguageList);
+            mAdapter.setDisplayedLanguages(mFullLanguageList);
             return false;
         });
 

chrome/android/java/src/org/chromium/chrome/browser/preferences/languages/LanguageListBaseAdapter.java

@@ -5,40 +5,33 @@
 package org.chromium.chrome.browser.preferences.languages;
 
 import android.content.Context;
-import android.content.res.Resources;
-import android.graphics.Color;
 import android.support.annotation.DrawableRes;
 import android.support.annotation.NonNull;
-import android.support.annotation.Nullable;
-import android.support.v4.graphics.ColorUtils;
 import android.support.v4.view.ViewCompat;
 import android.support.v7.widget.RecyclerView;
 import android.support.v7.widget.RecyclerView.ViewHolder;
-import android.support.v7.widget.helper.ItemTouchHelper;
 import android.text.TextUtils;
-import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.accessibility.AccessibilityManager;
+import android.view.accessibility.AccessibilityManager.AccessibilityStateChangeListener;
 import android.widget.ImageView;
 import android.widget.TextView;
 
-import org.chromium.base.ApiCompatibilityUtils;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.widget.ListMenuButton;
+import org.chromium.chrome.browser.widget.dragreorder.DragReorderableListAdapter;
+import org.chromium.chrome.browser.widget.dragreorder.DragStateDelegate;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 
 /**
  * BaseAdapter for {@link RecyclerView}. It manages languages to list there.
  */
-public class LanguageListBaseAdapter
-        extends RecyclerView.Adapter<LanguageListBaseAdapter.LanguageRowViewHolder> {
-    private static final int ANIMATION_DELAY_MS = 100;
-
+public class LanguageListBaseAdapter extends DragReorderableListAdapter<LanguageItem> {
     /**
      * Listener used to respond to click event on a language item.
      */
@@ -59,18 +52,18 @@ public class LanguageListBaseAdapter
         LanguageRowViewHolder(View view) {
             super(view);
 
-            mTitle = (TextView) view.findViewById(R.id.title);
-            mDescription = (TextView) view.findViewById(R.id.description);
+            mTitle = view.findViewById(R.id.title);
+            mDescription = view.findViewById(R.id.description);
 
             mStartIcon = view.findViewById(R.id.icon_view);
-            mMoreButton = (ListMenuButton) view.findViewById(R.id.more);
+            mMoreButton = view.findViewById(R.id.more);
         }
 
         /**
          * Update the current {@link LanguageRowViewHolder} with basic language info.
          * @param item A {@link LanguageItem} with the language details.
          */
-        private void updateLanguageInfo(LanguageItem item) {
+        protected void updateLanguageInfo(LanguageItem item) {
             mTitle.setText(item.getDisplayName());
 
             // Avoid duplicate display names.
@@ -83,7 +76,7 @@ public class LanguageListBaseAdapter
 
             mMoreButton.setContentDescriptionContext(item.getDisplayName());
 
-            // The default visibility for the views below is GONE.
+            // The more button will become visible if setMenuButtonDelegate is called.
             mStartIcon.setVisibility(View.GONE);
             mMoreButton.setVisibility(View.GONE);
         }
@@ -119,66 +112,61 @@ public class LanguageListBaseAdapter
         }
     }
 
-    private final int mDraggedBackgroundColor;
-    private final float mDraggedElevation;
-
-    private boolean mDragEnabled;
-    private ItemTouchHelper mItemTouchHelper;
-    private List<LanguageItem> mLanguageList;
-
-    protected Context mContext;
-
-    LanguageListBaseAdapter(Context context) {
-        mContext = context;
-        mLanguageList = new ArrayList<>();
-
-        Resources resource = context.getResources();
-        // Set the alpha to 90% when dragging which is 230/255
-        mDraggedBackgroundColor = ColorUtils.setAlphaComponent(
-                ApiCompatibilityUtils.getColor(resource, R.color.default_bg_color_elev_1),
-                resource.getInteger(R.integer.list_item_dragged_alpha));
-        mDraggedElevation = resource.getDimension(R.dimen.list_item_dragged_elevation);
-    }
-
-    @Override
-    public LanguageRowViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
-        View row = LayoutInflater.from(parent.getContext())
-                           .inflate(R.layout.accept_languages_item, parent, false);
-        return new LanguageRowViewHolder(row);
-    }
+    /**
+     * Keeps track of whether drag is enabled / active for language preference lists.
+     */
+    private class LanguageDragStateDelegate implements DragStateDelegate {
+        private AccessibilityManager mA11yManager;
+        private AccessibilityStateChangeListener mA11yListener;
+        private boolean mA11yEnabled;
+
+        public LanguageDragStateDelegate() {
+            mA11yManager =
+                    (AccessibilityManager) mContext.getSystemService(Context.ACCESSIBILITY_SERVICE);
+            mA11yEnabled = mA11yManager.isEnabled();
+            mA11yListener = enabled -> {
+                mA11yEnabled = enabled;
+                notifyDataSetChanged();
+            };
+            mA11yManager.addAccessibilityStateChangeListener(mA11yListener);
+        }
 
-    @Override
-    public void onBindViewHolder(LanguageRowViewHolder holder, int position) {
-        holder.updateLanguageInfo(mLanguageList.get(position));
-    }
+        // DragStateDelegate implementation
+        @Override
+        public boolean getDragEnabled() {
+            return !mA11yEnabled;
+        }
 
-    @Override
-    public int getItemCount() {
-        return mLanguageList.size();
-    }
+        @Override
+        public boolean getDragActive() {
+            return getDragEnabled();
+        }
 
-    LanguageItem getItemByPosition(int position) {
-        return mLanguageList.get(position);
+        @Override
+        public void setA11yStateForTesting(boolean a11yEnabled) {
+            mA11yManager.removeAccessibilityStateChangeListener(mA11yListener);
+            mA11yListener = null;
+            mA11yManager = null;
+            mA11yEnabled = a11yEnabled;
+        }
     }
 
-    void reload(List<LanguageItem> languageList) {
-        mLanguageList.clear();
-        mLanguageList.addAll(languageList);
-        notifyDataSetChanged();
+    LanguageListBaseAdapter(Context context) {
+        super(context);
+        setDragStateDelegate(new LanguageDragStateDelegate());
     }
 
     /**
      * Show a drag indicator at the start of the row if applicable.
      *
      * @param holder The LanguageRowViewHolder of the row.
-     * @param indicatorResId The identifier of the drawable resource for the indicator.
      */
-    void showDragIndicatorInRow(LanguageRowViewHolder holder, @DrawableRes int indicatorResId) {
+    void showDragIndicatorInRow(LanguageRowViewHolder holder) {
         // Quit if it's not applicable.
-        if (getItemCount() <= 1 || !mDragEnabled) return;
+        if (getItemCount() <= 1 || !mDragStateDelegate.getDragEnabled()) return;
 
         assert mItemTouchHelper != null;
-        holder.setStartIcon(indicatorResId);
+        holder.setStartIcon(R.drawable.ic_drag_handle_grey600_24dp);
         holder.mStartIcon.setOnTouchListener((v, event) -> {
             if (event.getActionMasked() == MotionEvent.ACTION_DOWN) {
                 mItemTouchHelper.startDrag(holder);
@@ -187,112 +175,46 @@ public class LanguageListBaseAdapter
         });
     }
 
-    /**
-     * Enables drag & drop interaction on the given RecyclerView.
-     * @param recyclerView The RecyclerView you want to drag from.
-     */
-    void enableDrag(RecyclerView recyclerView) {
-        mDragEnabled = true;
-
-        if (mItemTouchHelper == null) {
-            ItemTouchHelper.Callback touchHelperCallBack = new ItemTouchHelper.Callback() {
-
-                // The dragged language info during a single drag operation.
-                // The first is its start postion when it's dragged, the second is its language
-                // code.
-                @Nullable
-                private Pair<Integer, String> mDraggedLanguage;
-
-                @Override
-                public int getMovementFlags(RecyclerView recyclerView, ViewHolder viewHolder) {
-                    return makeMovementFlags(
-                            ItemTouchHelper.UP | ItemTouchHelper.DOWN, 0 /* swipe flags */);
-                }
-
-                @Override
-                public boolean onMove(
-                        RecyclerView recyclerView, ViewHolder current, ViewHolder target) {
-                    int from = current.getAdapterPosition();
-                    int to = target.getAdapterPosition();
-                    if (from == to) return false;
-
-                    Collections.swap(mLanguageList, from, to);
-                    notifyItemMoved(from, to);
-                    return true;
-                }
-
-                @Override
-                public void onSelectedChanged(ViewHolder viewHolder, int actionState) {
-                    super.onSelectedChanged(viewHolder, actionState);
-                    if (actionState == ItemTouchHelper.ACTION_STATE_DRAG) {
-                        // mDraggedLanguage should be cleaned up before.
-                        assert mDraggedLanguage == null;
-                        int start = viewHolder.getAdapterPosition();
-                        mDraggedLanguage = Pair.create(start, getItemByPosition(start).getCode());
-
-                        updateVisualState(true, viewHolder.itemView);
-                    }
-                }
-
-                @Override
-                public void clearView(RecyclerView recyclerView, ViewHolder viewHolder) {
-                    super.clearView(recyclerView, viewHolder);
-
-                    // Commit the postion change for the dragged language when it's dropped.
-                    if (mDraggedLanguage != null) {
-                        LanguagesManager.getInstance().moveLanguagePosition(mDraggedLanguage.second,
-                                viewHolder.getAdapterPosition() - mDraggedLanguage.first, false);
-                        mDraggedLanguage = null;
-                    }
-
-                    updateVisualState(false, viewHolder.itemView);
-                }
-
-                @Override
-                public boolean isLongPressDragEnabled() {
-                    return true;
-                }
-
-                @Override
-                public boolean isItemViewSwipeEnabled() {
-                    return false;
-                }
-
-                @Override
-                public void onSwiped(ViewHolder viewHolder, int direction) {
-                    // no-op
-                }
+    @Override
+    public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
+        View row = LayoutInflater.from(viewGroup.getContext())
+                           .inflate(R.layout.accept_languages_item, viewGroup, false);
+        return new LanguageRowViewHolder(row);
+    }
 
-                private void updateVisualState(boolean dragged, View view) {
-                    ViewCompat.animate(view)
-                            .translationZ(dragged ? mDraggedElevation : 0)
-                            .withEndAction(()
-                                                   -> view.setBackgroundColor(dragged
-                                                                   ? mDraggedBackgroundColor
-                                                                   : Color.TRANSPARENT))
-                            .setDuration(ANIMATION_DELAY_MS)
-                            .start();
-                }
-            };
+    @Override
+    public void onBindViewHolder(ViewHolder viewHolder, int i) {
+        ((LanguageRowViewHolder) viewHolder).updateLanguageInfo(mElements.get(i));
+    }
 
-            mItemTouchHelper = new ItemTouchHelper(touchHelperCallBack);
+    @Override
+    protected void setOrder(List<LanguageItem> order) {
+        String[] codes = new String[order.size()];
+        for (int i = 0; i < order.size(); i++) {
+            codes[i] = order.get(i).getCode();
         }
-        mItemTouchHelper.attachToRecyclerView(recyclerView);
+        LanguagesManager.getInstance().setOrder(codes, false);
+        notifyDataSetChanged();
     }
 
     /**
-     * Disables drag & drop interaction.
-     * @param recyclerView The RecyclerView you want to drag from.
+     * Sets the displayed languages (not the order of the user's preferred languages;
+     * see setOrder above).
+     *
+     * @param languages The language items to show.
      */
-    void disableDrag() {
-        mDragEnabled = false;
-        if (mItemTouchHelper != null) mItemTouchHelper.attachToRecyclerView(null);
+    void setDisplayedLanguages(List<LanguageItem> languages) {
+        mElements = new ArrayList<>(languages);
+        notifyDataSetChanged();
     }
 
-    /**
-     * Returns whether the drag & drop is enabled.
-     */
-    boolean isDragEnabled() {
-        return mDragEnabled;
+    @Override
+    protected boolean isActivelyDraggable(ViewHolder viewHolder) {
+        return isPassivelyDraggable(viewHolder);
+    }
+
+    @Override
+    protected boolean isPassivelyDraggable(ViewHolder viewHolder) {
+        return viewHolder instanceof LanguageRowViewHolder;
     }
 }

chrome/android/java/src/org/chromium/chrome/browser/preferences/languages/LanguageListPreference.java

@@ -10,13 +10,12 @@ import android.support.v7.preference.PreferenceViewHolder;
 import android.support.v7.widget.DividerItemDecoration;
 import android.support.v7.widget.LinearLayoutManager;
 import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.RecyclerView.ViewHolder;
 import android.util.AttributeSet;
-import android.view.accessibility.AccessibilityManager;
 import android.widget.TextView;
 
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.preferences.PrefServiceBridge;
-import org.chromium.chrome.browser.util.AccessibilityUtil;
 import org.chromium.chrome.browser.widget.ListMenuButton;
 import org.chromium.chrome.browser.widget.ListMenuButton.Item;
 import org.chromium.chrome.browser.widget.TintedDrawable;
@@ -35,14 +34,13 @@ public class LanguageListPreference extends Preference {
         }
 
         @Override
-        public void onBindViewHolder(
-                LanguageListBaseAdapter.LanguageRowViewHolder holder, int position) {
+        public void onBindViewHolder(ViewHolder holder, int position) {
             super.onBindViewHolder(holder, position);
 
-            showDragIndicatorInRow(holder, R.drawable.ic_drag_handle_grey600_24dp);
-
             final LanguageItem info = getItemByPosition(position);
-            holder.setMenuButtonDelegate(new ListMenuButton.Delegate() {
+
+            showDragIndicatorInRow((LanguageRowViewHolder) holder);
+            ((LanguageRowViewHolder) holder).setMenuButtonDelegate(new ListMenuButton.Delegate() {
                 @Override
                 public Item[] getItems() {
                     ArrayList<Item> menuItems = new ArrayList<>();
@@ -66,7 +64,7 @@ public class LanguageListPreference extends Preference {
 
                     // Add some appropriate options for moving the language when the list is not
                     // draggable. E.g. in the accessibility mode.
-                    if (!isDragEnabled()) {
+                    if (!mDragStateDelegate.getDragEnabled()) {
                         // Add "Move to top" and "Move up" menu when it's not the first one.
                         if (position > 0) {
                             menuItems.add(new Item(mContext, R.string.menu_item_move_to_top, true));
@@ -114,14 +112,18 @@ public class LanguageListPreference extends Preference {
 
         @Override
         public void onDataUpdated() {
-            reload(LanguagesManager.getInstance().getUserAcceptLanguageItems());
+            if (mDragStateDelegate.getDragActive()) {
+                enableDrag();
+            } else {
+                disableDrag();
+            }
+            setDisplayedLanguages(LanguagesManager.getInstance().getUserAcceptLanguageItems());
         }
     }
 
     private TextView mAddLanguageButton;
     private RecyclerView mRecyclerView;
     private LanguageListAdapter mAdapter;
-
     private AddLanguageFragment.Launcher mLauncher;
 
     public LanguageListPreference(Context context, AttributeSet attrs) {
@@ -152,27 +154,13 @@ public class LanguageListPreference extends Preference {
         mRecyclerView.addItemDecoration(
                 new DividerItemDecoration(getContext(), layoutMangager.getOrientation()));
 
-        // Due to a known native bug (crbug/640763), the list order written into Preference Service
-        // might be different from the order shown after it's adjusted by dragging.
-        if (!AccessibilityUtil.isAccessibilityEnabled()) mAdapter.enableDrag(mRecyclerView);
-        AccessibilityManager manager =
-                (AccessibilityManager) getContext().getSystemService(Context.ACCESSIBILITY_SERVICE);
-        manager.addAccessibilityStateChangeListener(enabled -> {
-            if (enabled) {
-                mAdapter.disableDrag();
-            } else {
-                mAdapter.enableDrag(mRecyclerView);
-            }
-            mAdapter.notifyDataSetChanged();
-        });
-
         // We do not want the RecyclerView to be announced by screen readers every time
         // the view is bound.
         if (mRecyclerView.getAdapter() != mAdapter) {
             mRecyclerView.setAdapter(mAdapter);
             LanguagesManager.getInstance().setAcceptLanguageObserver(mAdapter);
             // Initialize accept language list.
-            mAdapter.reload(LanguagesManager.getInstance().getUserAcceptLanguageItems());
+            mAdapter.onDataUpdated();
         }
     }
 

chrome/android/java/src/org/chromium/chrome/browser/preferences/languages/LanguagesManager.java

@@ -159,6 +159,18 @@ class LanguagesManager {
         if (reload) notifyAcceptLanguageObserver();
     }
 
+    /**
+     * Sets the preference order of the user's accepted languages to the provided order.
+     *
+     * @param codes The new order for the user's languages.
+     * @param reload True iff the language list should be reloaded.
+     */
+    public void setOrder(String[] codes, boolean reload) {
+        PrefServiceBridge.getInstance().setLanguageOrder(codes);
+        recordAction(LanguageSettingsActionType.LANGUAGE_LIST_REORDERED);
+        if (reload) notifyAcceptLanguageObserver();
+    }
+
     /**
      * Get the static instance of ChromePreferenceManager if it exists else create it.
      * @return the LanguagesManager singleton.

chrome/browser/android/preferences/pref_service_bridge.cc

@@ -1229,6 +1229,21 @@ static void JNI_PrefServiceBridge_GetUserAcceptLanguages(
       env, list, ToJavaArrayOfStrings(env, languages));
 }
 
+static void JNI_PrefServiceBridge_SetLanguageOrder(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    const JavaParamRef<jobjectArray>& j_order) {
+  std::unique_ptr<translate::TranslatePrefs> translate_prefs =
+      ChromeTranslateClient::CreateTranslatePrefs(GetPrefService());
+  std::vector<std::string> order;
+  const int num_langs = (*env).GetArrayLength(j_order);
+  for (int i = 0; i < num_langs; i++) {
+    jstring string = (jstring)(*env).GetObjectArrayElement(j_order, i);
+    order.push_back((*env).GetStringUTFChars(string, nullptr));
+  }
+  translate_prefs->SetLanguageOrder(order);
+}
+
 static void JNI_PrefServiceBridge_UpdateUserAcceptLanguages(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj,

components/translate/core/browser/translate_prefs.cc

@@ -368,6 +368,11 @@ void TranslatePrefs::RearrangeLanguage(
   }
 }
 
+void TranslatePrefs::SetLanguageOrder(
+    const std::vector<std::string>& new_order) {
+  UpdateLanguageList(new_order);
+}
+
 // static
 void TranslatePrefs::GetLanguageInfoList(
     const std::string& app_locale,

components/translate/core/browser/translate_prefs.h

@@ -206,6 +206,11 @@ class TranslatePrefs {
                          const int offset,
                          const std::vector<std::string>& enabled_languages);
 
+  // Sets the language order to the provided order.
+  // This function is called from the language preference manager in Chrome for
+  // Android.
+  void SetLanguageOrder(const std::vector<std::string>& new_order);
+
   // Returns the list of TranslateLanguageInfo for all languages that are
   // available in the given locale.
   // The list returned in |languages| is sorted alphabetically based on the