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BasicTransition / src / com.example.android.common / view /

SlidingTabStrip.java

       
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        /*
       
       
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        * Copyright (C) 2013 The Android Open Source Project
       
       
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        *
       
       
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        * Licensed under the Apache License, Version 2.0 (the "License");
       
       
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        * you may not use this file except in compliance with the License.
       
       
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        * You may obtain a copy of the License at
       
       
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        *
       
       
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        *      http://www.apache.org/licenses/LICENSE-2.0
       
       
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        *
       
       
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        * Unless required by applicable law or agreed to in writing, software
       
       
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        * distributed under the License is distributed on an "AS IS" BASIS,
       
       
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        * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
       
       
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        * See the License for the specific language governing permissions and
       
       
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        * limitations under the License.
       
       
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        */
       
       
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        package com.example.android.common.view;
       
       
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        import android.R;
       
       
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        import android.content.Context;
       
       
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        import android.graphics.Canvas;
       
       
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        import android.graphics.Color;
       
       
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        import android.graphics.Paint;
       
       
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        import android.util.AttributeSet;
       
       
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        import android.util.TypedValue;
       
       
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        import android.view.View;
       
       
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        import android.widget.LinearLayout;
       
       
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        class SlidingTabStrip extends LinearLayout {
       
       
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        private static final int DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS = 2;
       
       
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        private static final byte DEFAULT_BOTTOM_BORDER_COLOR_ALPHA = 0x26;
       
       
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        private static final int SELECTED_INDICATOR_THICKNESS_DIPS = 8;
       
       
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        private static final int DEFAULT_SELECTED_INDICATOR_COLOR = 0xFF33B5E5;
       
       
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        private static final int DEFAULT_DIVIDER_THICKNESS_DIPS = 1;
       
       
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        private static final byte DEFAULT_DIVIDER_COLOR_ALPHA = 0x20;
       
       
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        private static final float DEFAULT_DIVIDER_HEIGHT = 0.5f;
       
       
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        private final int mBottomBorderThickness;
       
       
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        private final Paint mBottomBorderPaint;
       
       
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        private final int mSelectedIndicatorThickness;
       
       
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        private final Paint mSelectedIndicatorPaint;
       
       
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        private final int mDefaultBottomBorderColor;
       
       
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        private final Paint mDividerPaint;
       
       
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        private final float mDividerHeight;
       
       
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        private int mSelectedPosition;
       
       
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        private float mSelectionOffset;
       
       
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        private SlidingTabLayout.TabColorizer mCustomTabColorizer;
       
       
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        private final SimpleTabColorizer mDefaultTabColorizer;
       
       
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        SlidingTabStrip(Context context) {
       
       
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        this(context, null);
       
       
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        }
       
       
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        SlidingTabStrip(Context context, AttributeSet attrs) {
       
       
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        super(context, attrs);
       
       
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        setWillNotDraw(false);
       
       
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        final float density = getResources().getDisplayMetrics().density;
       
       
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        TypedValue outValue = new TypedValue();
       
       
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        context.getTheme().resolveAttribute(R.attr.colorForeground, outValue, true);
       
       
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        final int themeForegroundColor =  outValue.data;
       
       
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        mDefaultBottomBorderColor = setColorAlpha(themeForegroundColor,
       
       
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        DEFAULT_BOTTOM_BORDER_COLOR_ALPHA);
       
       
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        mDefaultTabColorizer = new SimpleTabColorizer();
       
       
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        mDefaultTabColorizer.setIndicatorColors(DEFAULT_SELECTED_INDICATOR_COLOR);
       
       
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        mDefaultTabColorizer.setDividerColors(setColorAlpha(themeForegroundColor,
       
       
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        DEFAULT_DIVIDER_COLOR_ALPHA));
       
       
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        mBottomBorderThickness = (int) (DEFAULT_BOTTOM_BORDER_THICKNESS_DIPS * density);
       
       
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        mBottomBorderPaint = new Paint();
       
       
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        mBottomBorderPaint.setColor(mDefaultBottomBorderColor);
       
       
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        mSelectedIndicatorThickness = (int) (SELECTED_INDICATOR_THICKNESS_DIPS * density);
       
       
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        mSelectedIndicatorPaint = new Paint();
       
       
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        mDividerHeight = DEFAULT_DIVIDER_HEIGHT;
       
       
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        mDividerPaint = new Paint();
       
       
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        mDividerPaint.setStrokeWidth((int) (DEFAULT_DIVIDER_THICKNESS_DIPS * density));
       
       
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        }
       
       
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        void setCustomTabColorizer(SlidingTabLayout.TabColorizer customTabColorizer) {
       
       
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        mCustomTabColorizer = customTabColorizer;
       
       
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        invalidate();
       
       
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        }
       
       
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        void setSelectedIndicatorColors(int... colors) {
       
       
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        // Make sure that the custom colorizer is removed
       
       
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        mCustomTabColorizer = null;
       
       
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        mDefaultTabColorizer.setIndicatorColors(colors);
       
       
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        invalidate();
       
       
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        }
       
       
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        void setDividerColors(int... colors) {
       
       
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        // Make sure that the custom colorizer is removed
       
       
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        mCustomTabColorizer = null;
       
       
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        mDefaultTabColorizer.setDividerColors(colors);
       
       
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        invalidate();
       
       
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        }
       
       
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        void onViewPagerPageChanged(int position, float positionOffset) {
       
       
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        mSelectedPosition = position;
       
       
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        mSelectionOffset = positionOffset;
       
       
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        invalidate();
       
       
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        }
       
       
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        @Override
       
       
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        protected void onDraw(Canvas canvas) {
       
       
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        final int height = getHeight();
       
       
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        final int childCount = getChildCount();
       
       
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        final int dividerHeightPx = (int) (Math.min(Math.max(0f, mDividerHeight), 1f) * height);
       
       
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        final SlidingTabLayout.TabColorizer tabColorizer = mCustomTabColorizer != null
       
       
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        ? mCustomTabColorizer
       
       
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        : mDefaultTabColorizer;
       
       
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        // Thick colored underline below the current selection
       
       
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        if (childCount > 0) {
       
       
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        View selectedTitle = getChildAt(mSelectedPosition);
       
       
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        int left = selectedTitle.getLeft();
       
       
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        int right = selectedTitle.getRight();
       
       
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        int color = tabColorizer.getIndicatorColor(mSelectedPosition);
       
       
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        if (mSelectionOffset > 0f && mSelectedPosition < (getChildCount() - 1)) {
       
       
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        int nextColor = tabColorizer.getIndicatorColor(mSelectedPosition + 1);
       
       
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        if (color != nextColor) {
       
       
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        color = blendColors(nextColor, color, mSelectionOffset);
       
       
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        }
       
       
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        // Draw the selection partway between the tabs
       
       
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        View nextTitle = getChildAt(mSelectedPosition + 1);
       
       
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        left = (int) (mSelectionOffset * nextTitle.getLeft() +
       
       
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        (1.0f - mSelectionOffset) * left);
       
       
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        right = (int) (mSelectionOffset * nextTitle.getRight() +
       
       
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        (1.0f - mSelectionOffset) * right);
       
       
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        }
       
       
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        mSelectedIndicatorPaint.setColor(color);
       
       
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        canvas.drawRect(left, height - mSelectedIndicatorThickness, right,
       
       
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        height, mSelectedIndicatorPaint);
       
       
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        }
       
       
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        // Thin underline along the entire bottom edge
       
       
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        canvas.drawRect(0, height - mBottomBorderThickness, getWidth(), height, mBottomBorderPaint);
       
       
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        // Vertical separators between the titles
       
       
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        int separatorTop = (height - dividerHeightPx) / 2;
       
       
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        for (int i = 0; i < childCount - 1; i++) {
       
       
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        View child = getChildAt(i);
       
       
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        mDividerPaint.setColor(tabColorizer.getDividerColor(i));
       
       
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        canvas.drawLine(child.getRight(), separatorTop, child.getRight(),
       
       
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        separatorTop + dividerHeightPx, mDividerPaint);
       
       
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        }
       
       
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        }
       
       
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        /**
       
       
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        * Set the alpha value of the {@code color} to be the given {@code alpha} value.
       
       
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        */
       
       
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        private static int setColorAlpha(int color, byte alpha) {
       
       
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        return Color.argb(alpha, Color.red(color), Color.green(color), Color.blue(color));
       
       
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        }
       
       
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        /**
       
       
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        * Blend {@code color1} and {@code color2} using the given ratio.
       
       
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        *
       
       
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        * @param ratio of which to blend. 1.0 will return {@code color1}, 0.5 will give an even blend,
       
       
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        *              0.0 will return {@code color2}.
       
       
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        */
       
       
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        private static int blendColors(int color1, int color2, float ratio) {
       
       
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        final float inverseRation = 1f - ratio;
       
       
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        float r = (Color.red(color1) * ratio) + (Color.red(color2) * inverseRation);
       
       
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        float g = (Color.green(color1) * ratio) + (Color.green(color2) * inverseRation);
       
       
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        float b = (Color.blue(color1) * ratio) + (Color.blue(color2) * inverseRation);
       
       
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        return Color.rgb((int) r, (int) g, (int) b);
       
       
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        }
       
       
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        private static class SimpleTabColorizer implements SlidingTabLayout.TabColorizer {
       
       
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        private int[] mIndicatorColors;
       
       
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        private int[] mDividerColors;
       
       
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        @Override
       
       
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        public final int getIndicatorColor(int position) {
       
       
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        return mIndicatorColors[position % mIndicatorColors.length];
       
       
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        }
       
       
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        @Override
       
       
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        public final int getDividerColor(int position) {
       
       
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        return mDividerColors[position % mDividerColors.length];
       
       
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        }
       
       
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        void setIndicatorColors(int... colors) {
       
       
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        mIndicatorColors = colors;
       
       
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        }
       
       
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        void setDividerColors(int... colors) {
       
       
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        mDividerColors = colors;
       
       
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        }
       
       
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        }
       
       
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        }