Bug 1116415 - 3. Add an ItemTouchHelper to the tabs panel list for swipe to close. r=sebastian

MozReview-Commit-ID: 8QlbSg7qsZK

--HG--
extra : rebase_source : 40f57bbb8f2a97903cf52c5ce5d134d67ab957bb
extra : source : 332092b1cb5ecb3d99f93a21edce5ab3bcb00fd5

mobile/android/base/java/org/mozilla/gecko/tabs/TabsLayout.java

@@ -23,7 +23,8 @@ import java.util.ArrayList;
 public abstract class TabsLayout extends RecyclerView
         implements TabsPanel.TabsLayout,
         Tabs.OnTabsChangedListener,
-        RecyclerViewClickSupport.OnItemClickListener {
+        RecyclerViewClickSupport.OnItemClickListener,
+        TabsTouchHelperCallback.DismissListener {
 
     private static final String LOGTAG = "Gecko" + TabsLayout.class.getSimpleName();
 
@@ -174,6 +175,11 @@ public abstract class TabsLayout extends RecyclerView
         }
     }
 
+    @Override
+    public void onItemDismiss(View view) {
+        closeTab(view);
+    }
+
     private Tab getTabForView(View view) {
         if (view == null) {
             return null;

mobile/android/base/java/org/mozilla/gecko/tabs/TabsListLayout.java

@@ -11,6 +11,7 @@ import org.mozilla.gecko.util.ThreadUtils;
 
 import android.content.Context;
 import android.support.v7.widget.LinearLayoutManager;
+import android.support.v7.widget.helper.ItemTouchHelper;
 import android.util.AttributeSet;
 import android.view.View;
 
@@ -29,6 +30,11 @@ public class TabsListLayout extends TabsLayout {
         setHasFixedSize(true);
 
         setLayoutManager(new LinearLayoutManager(context));
+
+        // A TouchHelper handler for swipe to close.
+        final TabsTouchHelperCallback callback = new TabsTouchHelperCallback(this);
+        final ItemTouchHelper touchHelper = new ItemTouchHelper(callback);
+        touchHelper.attachToRecyclerView(this);
     }
 
     @Override

mobile/android/base/java/org/mozilla/gecko/tabs/TabsTouchHelperCallback.java

@@ -0,0 +1,69 @@
+/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+package org.mozilla.gecko.tabs;
+
+import android.graphics.Canvas;
+import android.support.v7.widget.RecyclerView;
+import android.support.v7.widget.helper.ItemTouchHelper;
+import android.view.View;
+
+class TabsTouchHelperCallback extends ItemTouchHelper.Callback {
+    private final DismissListener dismissListener;
+
+    interface DismissListener {
+        void onItemDismiss(View view);
+    }
+
+    public TabsTouchHelperCallback(DismissListener dismissListener) {
+        this.dismissListener = dismissListener;
+    }
+
+    @Override
+    public boolean isItemViewSwipeEnabled() {
+        return true;
+    }
+
+    @Override
+    public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
+        return makeFlag(ItemTouchHelper.ACTION_STATE_SWIPE, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT);
+    }
+
+    @Override
+    public void onSwiped(RecyclerView.ViewHolder viewHolder, int i) {
+        dismissListener.onItemDismiss(viewHolder.itemView);
+    }
+
+    @Override
+    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder,
+                          RecyclerView.ViewHolder target) {
+        return false;
+    }
+
+    // Alpha on an itemView being swiped should decrease to a min over a distance equal to the
+    // width of the item being swiped.
+    @Override
+    public void onChildDraw(Canvas c,
+                            RecyclerView recyclerView,
+                            RecyclerView.ViewHolder viewHolder,
+                            float dX,
+                            float dY,
+                            int actionState,
+                            boolean isCurrentlyActive) {
+        if (actionState != ItemTouchHelper.ACTION_STATE_SWIPE) {
+            return;
+        }
+
+        super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
+
+        viewHolder.itemView.setAlpha(Math.max(0.1f,
+                Math.min(1f, 1f - 2f * Math.abs(dX) / viewHolder.itemView.getWidth())));
+    }
+
+    public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
+        super.clearView(recyclerView, viewHolder);
+        viewHolder.itemView.setAlpha(1);
+    }
+}

mobile/android/base/moz.build

@@ -674,6 +674,7 @@ gbjar.sources += ['java/org/mozilla/gecko/' + x for x in [
     'tabs/TabsListLayout.java',
     'tabs/TabsPanel.java',
     'tabs/TabsPanelThumbnailView.java',
+    'tabs/TabsTouchHelperCallback.java',
     'Telemetry.java',
     'telemetry/measurements/CampaignIdMeasurements.java',
     'telemetry/measurements/SearchCountMeasurements.java',