Display setting and support in a tab layout - DO NOT MERGE

Bug: 28269035
Bug: 28139604

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

@@ -0,0 +1,168 @@
+/*
+ * 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.PagerAdapter;
+import android.support.v4.view.ViewPager;
+import android.util.AttributeSet;
+import android.view.Gravity;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.widget.FrameLayout;
+import android.widget.LinearLayout;
+import android.widget.TextView;
+
+import com.android.settings.R;
+
+/**
+ * To be used with ViewPager to provide a tab indicator component which give constant feedback as
+ * to the user's scroll progress.
+ */
+public final class SlidingTabLayout extends FrameLayout implements View.OnClickListener {
+
+    private final LinearLayout mTitleView;
+    private final View mIndicatorView;
+    private final LayoutInflater mLayoutInflater;
+
+    private ViewPager mViewPager;
+    private int mSelectedPosition;
+    private float mSelectionOffset;
+
+    public SlidingTabLayout(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        mLayoutInflater = LayoutInflater.from(context);
+        mTitleView = new LinearLayout(context);
+        mTitleView.setGravity(Gravity.CENTER_HORIZONTAL);
+        mIndicatorView = mLayoutInflater.inflate(R.layout.sliding_tab_indicator_view, this, false);
+
+        addView(mTitleView, LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
+        addView(mIndicatorView, mIndicatorView.getLayoutParams());
+    }
+
+    /**
+     * 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) {
+        mTitleView.removeAllViews();
+
+        mViewPager = viewPager;
+        if (viewPager != null) {
+            viewPager.addOnPageChangeListener(new InternalViewPagerListener());
+            populateTabStrip();
+        }
+    }
+
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+        final int titleCount = mTitleView.getChildCount();
+        if (titleCount > 0) {
+            final int width = MeasureSpec.makeMeasureSpec(
+                    mTitleView.getMeasuredWidth() / titleCount, MeasureSpec.EXACTLY);
+            final int height = MeasureSpec.makeMeasureSpec(
+                    mIndicatorView.getMeasuredHeight(), MeasureSpec.EXACTLY);
+            mIndicatorView.measure(width, height);
+        }
+    }
+
+    @Override
+    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
+        if (mTitleView.getChildCount() > 0) {
+            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);
+        }
+    }
+
+    @Override
+    public void onClick(View v) {
+        final int titleCount = mTitleView.getChildCount();
+        for (int i = 0; i < titleCount; i++) {
+            if (v == mTitleView.getChildAt(i)) {
+                mViewPager.setCurrentItem(i);
+                return;
+            }
+        }
+    }
+
+    private void onViewPagerPageChanged(int position, float positionOffset) {
+        mSelectedPosition = position;
+        mSelectionOffset = positionOffset;
+        mIndicatorView.setTranslationX(getIndicatorLeft());
+    }
+
+    private void populateTabStrip() {
+        final PagerAdapter adapter = mViewPager.getAdapter();
+
+        for (int i = 0; i < adapter.getCount(); i++) {
+            final TextView tabTitleView = (TextView) mLayoutInflater.inflate(
+                    R.layout.sliding_tab_title_view, mTitleView, false);
+
+            tabTitleView.setText(adapter.getPageTitle(i));
+            tabTitleView.setOnClickListener(this);
+
+            mTitleView.addView(tabTitleView);
+            if (i == mViewPager.getCurrentItem()) {
+                tabTitleView.setSelected(true);
+            }
+        }
+    }
+
+    private int getIndicatorLeft() {
+        View selectedTitle = mTitleView.getChildAt(mSelectedPosition);
+        int left = selectedTitle.getLeft();
+        if (mSelectionOffset > 0f && mSelectedPosition < (getChildCount() - 1)) {
+            View nextTitle = mTitleView.getChildAt(mSelectedPosition + 1);
+            left = (int) (mSelectionOffset * nextTitle.getLeft()
+                    + (1.0f - mSelectionOffset) * left);
+        }
+        return left;
+    }
+
+    private final class InternalViewPagerListener implements ViewPager.OnPageChangeListener {
+        private int mScrollState;
+
+        @Override
+        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
+            final int titleCount = mTitleView.getChildCount();
+            if ((titleCount == 0) || (position < 0) || (position >= titleCount)) {
+                return;
+            }
+            onViewPagerPageChanged(position, positionOffset);
+        }
+
+        @Override
+        public void onPageScrollStateChanged(int state) {
+            mScrollState = state;
+        }
+
+        @Override
+        public void onPageSelected(int position) {
+            if (mScrollState == ViewPager.SCROLL_STATE_IDLE) {
+                onViewPagerPageChanged(position, 0f);
+            }
+            final int titleCount = getChildCount();
+            for (int i = 0; i < titleCount; i++) {
+                getChildAt(i).setSelected(position == i);
+            }
+        }
+    }
+}