Merge \\"Settings ViewPager now correctly handles RTL mode\\" into nyc-mr1-dev am: b8257e6fee

am: b51d45aed0

Change-Id: I654d8fee969fe089b79d77af8135ac9fc3fdc309

src/com/android/settings/widget/RtlCompatibleViewPager.java

@@ -0,0 +1,73 @@
+/*
+ * 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.settings.widget;
+
+import android.content.Context;
+import android.support.v4.view.ViewPager;
+import android.text.TextUtils;
+import android.util.AttributeSet;
+import android.view.View;
+
+import java.util.Locale;
+
+/**
+ * A {@link ViewPager} that's aware of RTL changes when used with FragmentPagerAdapter.
+ */
+public final class RtlCompatibleViewPager extends ViewPager {
+
+    /**
+     * Callback interface for responding to changing state of the selected page.
+     * Positions supplied will always be the logical position in the adapter -
+     * that is, the 0 index corresponds to the left-most page in LTR and the
+     * right-most page in RTL.
+     */
+
+    public RtlCompatibleViewPager(Context context) {
+        this(context, null /* attrs */);
+    }
+
+    public RtlCompatibleViewPager(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    @Override
+    public int getCurrentItem() {
+        return getRtlAwareIndex(super.getCurrentItem());
+    }
+
+    @Override
+    public void setCurrentItem(int item) {
+        super.setCurrentItem(getRtlAwareIndex(item));
+    }
+
+    /**
+     * Get a "RTL friendly" index. If the locale is LTR, the index is returned as is.
+     * Otherwise it's transformed so view pager can render views using the new index for RTL. For
+     * example, the second view will be rendered to the left of first view.
+     *
+     * @param index The logical index.
+     */
+    public int getRtlAwareIndex(int index) {
+        // Using TextUtils rather than View.getLayoutDirection() because LayoutDirection is not
+        // defined until onMeasure, and this is called before then.
+        if (TextUtils.getLayoutDirectionFromLocale(Locale.getDefault())
+                == View.LAYOUT_DIRECTION_RTL) {
+            return getAdapter().getCount() - index - 1;
+        }
+        return index;
+    }
+}

src/com/android/settings/widget/SlidingTabLayout.java

@@ -18,7 +18,6 @@ package com.android.settings.widget;
 
 import android.content.Context;
 import android.support.v4.view.PagerAdapter;
-import android.support.v4.view.ViewPager;
 import android.util.AttributeSet;
 import android.view.Gravity;
 import android.view.LayoutInflater;
@@ -39,7 +38,7 @@ public final class SlidingTabLayout extends FrameLayout implements View.OnClickL
     private final View mIndicatorView;
     private final LayoutInflater mLayoutInflater;
 
-    private ViewPager mViewPager;
+    private RtlCompatibleViewPager mViewPager;
     private int mSelectedPosition;
     private float mSelectionOffset;
 
@@ -58,7 +57,7 @@ public final class SlidingTabLayout extends FrameLayout implements View.OnClickL
      * Sets the associated view pager. Note that the assumption here is that the pager content
      * (number of tabs and tab titles) does not change after this call has been made.
      */
-    public void setViewPager(ViewPager viewPager) {
+    public void setViewPager(RtlCompatibleViewPager viewPager) {
         mTitleView.removeAllViews();
 
         mViewPager = viewPager;
@@ -87,8 +86,19 @@ public final class SlidingTabLayout extends FrameLayout implements View.OnClickL
             mTitleView.layout(0, 0, mTitleView.getMeasuredWidth(), mTitleView.getMeasuredHeight());
             final int indicatorBottom = getMeasuredHeight();
             final int indicatorHeight = mIndicatorView.getMeasuredHeight();
-            mIndicatorView.layout(0, indicatorBottom - indicatorHeight,
-                    mIndicatorView.getMeasuredWidth(), indicatorBottom);
+            final int indicatorWidth = mIndicatorView.getMeasuredWidth();
+            final int totalWidth = getMeasuredWidth();
+
+            // IndicatorView should start on the right when RTL mode is enabled
+            if (isRtlMode()) {
+                mIndicatorView.layout(totalWidth - indicatorWidth,
+                        indicatorBottom - indicatorHeight, totalWidth,
+                        indicatorBottom);
+            } else {
+
+                mIndicatorView.layout(0, indicatorBottom - indicatorHeight,
+                        indicatorWidth, indicatorBottom);
+            }
         }
     }
 
@@ -106,7 +116,9 @@ public final class SlidingTabLayout extends FrameLayout implements View.OnClickL
     private void onViewPagerPageChanged(int position, float positionOffset) {
         mSelectedPosition = position;
         mSelectionOffset = positionOffset;
-        mIndicatorView.setTranslationX(getIndicatorLeft());
+        // Translation should be reversed in RTL mode
+        final int leftIndicator = isRtlMode() ? -getIndicatorLeft() : getIndicatorLeft();
+        mIndicatorView.setTranslationX(leftIndicator);
     }
 
     private void populateTabStrip() {
@@ -135,7 +147,12 @@ public final class SlidingTabLayout extends FrameLayout implements View.OnClickL
         return left;
     }
 
-    private final class InternalViewPagerListener implements ViewPager.OnPageChangeListener {
+    private boolean isRtlMode() {
+        return getLayoutDirection() == LAYOUT_DIRECTION_RTL;
+    }
+
+    private final class InternalViewPagerListener implements
+            RtlCompatibleViewPager.OnPageChangeListener {
         private int mScrollState;
 
         @Override
@@ -154,7 +171,8 @@ public final class SlidingTabLayout extends FrameLayout implements View.OnClickL
 
         @Override
         public void onPageSelected(int position) {
-            if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
+            position = mViewPager.getRtlAwareIndex(position);
+            if (mScrollState == RtlCompatibleViewPager.SCROLL_STATE_IDLE) {
                 onViewPagerPageChanged(position, 0f);
             }
             final int titleCount = mTitleView.getChildCount();