Bug 1317446 - 3. Add TabStripDividerItem for TabStripView dividers and spacing. r=sebastian

MozReview-Commit-ID: 5OC58tEGQrM

--HG--
extra : rebase_source : 50272cc5990fa3fb409a103575a2ff739daf825e
extra : source : 542d785801381ce681377c4dbb27b43edd7cdbd7

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

@@ -0,0 +1,90 @@
+/* -*- 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 org.mozilla.gecko.R;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.graphics.Rect;
+import android.support.v4.content.ContextCompat;
+import android.support.v7.widget.RecyclerView;
+import android.view.View;
+
+class TabStripDividerItem extends RecyclerView.ItemDecoration {
+    private final int margin;
+    private final int dividerWidth;
+    private final int dividerHeight;
+    private final int dividerPaddingBottom;
+    private final Paint dividerPaint;
+
+    TabStripDividerItem(Context context) {
+        margin = (int) context.getResources().getDimension(R.dimen.tablet_tab_strip_item_margin);
+        dividerWidth = (int) context.getResources().getDimension(R.dimen.tablet_tab_strip_divider_width);
+        dividerHeight = (int) context.getResources().getDimension(R.dimen.tablet_tab_strip_divider_height);
+        dividerPaddingBottom = (int) context.getResources().getDimension(R.dimen.tablet_tab_strip_divider_padding_bottom);
+
+        dividerPaint = new Paint();
+        dividerPaint.setColor(ContextCompat.getColor(context, R.color.tablet_tab_strip_divider_color));
+        dividerPaint.setStyle(Paint.Style.FILL_AND_STROKE);
+    }
+
+    /**
+     * Return whether a divider should be drawn on the left side of the tab represented by
+     * {@code view}.
+     */
+    private static boolean drawLeftDividerForView(View view, RecyclerView parent) {
+        final int position = parent.getChildAdapterPosition(view);
+        // No left divider if this is tab 0 or this tab is currently pressed.
+        if (position == 0 || view.isPressed()) {
+            return false;
+        }
+
+        final int selectedPosition = ((TabStripView) parent).getPositionForSelectedTab();
+        // No left divider if this tab or the previous tab is the current selected tab.
+        if (selectedPosition != RecyclerView.NO_POSITION &&
+                (position == selectedPosition || position == selectedPosition + 1)) {
+            return false;
+        }
+
+        final RecyclerView.ViewHolder holder = parent.findViewHolderForAdapterPosition(position - 1);
+        // No left divider if the previous tab is currently pressed.
+        if (holder != null && holder.itemView.isPressed()) {
+            return false;
+        }
+
+        return true;
+    }
+
+    @Override
+    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
+        final int position = parent.getChildAdapterPosition(view);
+        final int leftOffset = position == 0 ? 0 : margin;
+        final int rightOffset = position == parent.getAdapter().getItemCount() - 1 ? 0 : margin;
+
+        outRect.set(leftOffset, 0, rightOffset, 0);
+    }
+
+    @Override
+    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
+        final int childCount = parent.getChildCount();
+        if (childCount == 0) {
+            return;
+        }
+
+        for (int i = 0; i < childCount; i++) {
+            final View child = parent.getChildAt(i);
+            if (drawLeftDividerForView(child, parent)) {
+                final float left = child.getLeft() + child.getTranslationX() + Math.abs(margin);
+                final float top = child.getTop() + child.getTranslationY();
+                final float dividerTop = top + child.getHeight() - dividerHeight - dividerPaddingBottom;
+                final float dividerBottom = dividerTop + dividerHeight;
+                c.drawRect(left - dividerWidth, dividerTop, left, dividerBottom, dividerPaint);
+            }
+        }
+    }
+}

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

@@ -51,6 +51,8 @@ public class TabStripView extends RecyclerView {
 
         animatorListener = new TabAnimatorListener();
 
+        setChildrenDrawingOrderEnabled(true);
+
         adapter = new TabStripAdapter(context);
         setAdapter(adapter);
 
@@ -60,7 +62,7 @@ public class TabStripView extends RecyclerView {
 
         setItemAnimator(new TabStripItemAnimator(ANIM_TIME_MS));
 
-        // TODO add item decoration.
+        addItemDecoration(new TabStripDividerItem(context));
     }
 
     /* package */ void refreshTabs() {
@@ -124,8 +126,12 @@ public class TabStripView extends RecyclerView {
         adapter.notifyTabChanged(tab);
     }
 
+    public int getPositionForSelectedTab() {
+        return adapter.getPositionForTab(Tabs.getInstance().getSelectedTab());
+    }
+
     private void updateSelectedPosition() {
-        final int selected = adapter.getPositionForTab(Tabs.getInstance().getSelectedTab());
+        final int selected = getPositionForSelectedTab();
         if (selected != -1) {
             scrollToPosition(selected);
         }
@@ -150,6 +156,45 @@ public class TabStripView extends RecyclerView {
         child.setTranslationY(0);
     }
 
+    /**
+     * Return the position of the currently selected tab relative to the tabs currently visible in
+     * the tabs list, or -1 if the currently selected tab isn't visible in the tabs list.
+     */
+    private int getRelativeSelectedPosition(int visibleTabsCount) {
+        final int selectedPosition = getPositionForSelectedTab();
+        final LinearLayoutManager layoutManager = (LinearLayoutManager) getLayoutManager();
+        final int firstVisiblePosition = layoutManager.findFirstVisibleItemPosition();
+        final int relativeSelectedPosition = selectedPosition - firstVisiblePosition;
+        if (relativeSelectedPosition < 0 || relativeSelectedPosition > visibleTabsCount - 1) {
+            return -1;
+        }
+
+        return relativeSelectedPosition;
+    }
+
+    @Override
+    protected int getChildDrawingOrder(int childCount, int i) {
+        final int relativeSelectedPosition = getRelativeSelectedPosition(childCount);
+        if (relativeSelectedPosition == -1) {
+            // The selected tab isn't visible, so we don't need to adjust drawing order.
+            return i;
+        }
+
+        // Explanation of the input parameters: there are childCount tabs visible, and right now
+        // we're returning which of those tabs to draw i'th, for some i between 0 and
+        // childCount - 1.
+        if (i == childCount - 1) {
+            // Draw the selected tab last.
+            return relativeSelectedPosition;
+        } else if (i >= relativeSelectedPosition) {
+            // Draw the tabs after the selected tab one iteration earlier than normal.
+            return i + 1;
+        } else {
+            // Draw the tabs before the selected tab in their normal order.
+            return i;
+        }
+    }
+
     @Override
     protected void onSizeChanged(int w, int h, int oldw, int oldh) {
         super.onSizeChanged(w, h, oldw, oldh);

mobile/android/base/moz.build

@@ -855,6 +855,7 @@ if max_sdk_version >= 11:
     gbjar.sources += ['java/org/mozilla/gecko/' + x for x in [
         'tabs/TabStrip.java',
         'tabs/TabStripAdapter.java',
+        'tabs/TabStripDividerItem.java',
         'tabs/TabStripItemAnimator.java',
         'tabs/TabStripItemView.java',
         'tabs/TabStripView.java'

mobile/android/base/resources/values/colors.xml

@@ -145,4 +145,6 @@
   <color name="activity_stream_timestamp">#FFD3D3D3</color>
   <color name="activity_stream_icon">#FF919191</color>
 
+  <color name="tablet_tab_strip_divider_color">#555555</color>
+
 </resources>

mobile/android/base/resources/values/dimens.xml

@@ -43,6 +43,10 @@
     <dimen name="tablet_tab_strip_height">48dp</dimen>
     <dimen name="tablet_tab_strip_item_width">208dp</dimen>
     <dimen name="tablet_tab_strip_fading_edge_size">15dp</dimen>
+    <dimen name="tablet_tab_strip_item_margin">-14dp</dimen>
+    <dimen name="tablet_tab_strip_divider_width">1dp</dimen>
+    <dimen name="tablet_tab_strip_divider_height">30dp</dimen>
+    <dimen name="tablet_tab_strip_divider_padding_bottom">6dp</dimen>
     <dimen name="tablet_browser_toolbar_menu_item_width">56dp</dimen>
     <!-- Padding combines with an 18dp image to form the menu item width and height. -->
     <dimen name="tablet_browser_toolbar_menu_item_padding_horizontal">19dp</dimen>