/*
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* Copyright (C) 2012 Jake Wharton
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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.viewpagerindicator;
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import android.content.Context;
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import android.content.res.Resources;
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import android.content.res.TypedArray;
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import android.graphics.Canvas;
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import android.graphics.Paint;
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import android.graphics.drawable.Drawable;
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import android.os.Parcel;
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import android.os.Parcelable;
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import androidx.core.view.MotionEventCompat;
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import androidx.core.view.ViewConfigurationCompat;
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import androidx.viewpager.widget.ViewPager;
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import android.util.AttributeSet;
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import android.view.MotionEvent;
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import android.view.View;
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import android.view.ViewConfiguration;
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/**
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* Draws a line for each page. The current page line is colored differently than
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* the unselected page lines.
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*/
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public class LinePageIndicator extends View implements PageIndicator {
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private static final int INVALID_POINTER = -1;
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private final Paint mPaintUnselected = new Paint(Paint.ANTI_ALIAS_FLAG);
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private final Paint mPaintSelected = new Paint(Paint.ANTI_ALIAS_FLAG);
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private ViewPager mViewPager;
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private ViewPager.OnPageChangeListener mListener;
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private int mCurrentPage;
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private boolean mCentered;
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private float mLineWidth;
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private float mGapWidth;
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private int mTouchSlop;
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private float mLastMotionX = -1;
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private int mActivePointerId = INVALID_POINTER;
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private boolean mIsDragging;
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public LinePageIndicator(Context context) {
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this(context, null);
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}
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public LinePageIndicator(Context context, AttributeSet attrs) {
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this(context, attrs, R.attr.vpiLinePageIndicatorStyle);
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}
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public LinePageIndicator(Context context, AttributeSet attrs, int defStyle) {
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super(context, attrs, defStyle);
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if (isInEditMode())
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return;
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final Resources res = getResources();
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// Load defaults from resources
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final int defaultSelectedColor = res
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.getColor(R.color.default_line_indicator_selected_color);
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final int defaultUnselectedColor = res
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.getColor(R.color.default_line_indicator_unselected_color);
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final float defaultLineWidth = res
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.getDimension(R.dimen.default_line_indicator_line_width);
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final float defaultGapWidth = res
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.getDimension(R.dimen.default_line_indicator_gap_width);
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final float defaultStrokeWidth = res
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.getDimension(R.dimen.default_line_indicator_stroke_width);
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final boolean defaultCentered = res
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.getBoolean(R.bool.default_line_indicator_centered);
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// Retrieve styles attributes
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TypedArray a = context.obtainStyledAttributes(attrs,
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R.styleable.LinePageIndicator, defStyle, 0);
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mCentered = a.getBoolean(R.styleable.LinePageIndicator_centered,
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defaultCentered);
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mLineWidth = a.getDimension(R.styleable.LinePageIndicator_lineWidth,
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defaultLineWidth);
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mGapWidth = a.getDimension(R.styleable.LinePageIndicator_gapWidth,
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defaultGapWidth);
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setStrokeWidth(a.getDimension(
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R.styleable.LinePageIndicator_strokeWidth, defaultStrokeWidth));
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mPaintUnselected.setColor(a.getColor(
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R.styleable.LinePageIndicator_unselectedColor,
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defaultUnselectedColor));
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mPaintSelected.setColor(a.getColor(
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R.styleable.LinePageIndicator_selectedColor,
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defaultSelectedColor));
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Drawable background = a
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.getDrawable(R.styleable.LinePageIndicator_android_background);
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if (background != null) {
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setBackgroundDrawable(background);
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}
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a.recycle();
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final ViewConfiguration configuration = ViewConfiguration.get(context);
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mTouchSlop = ViewConfigurationCompat
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.getScaledPagingTouchSlop(configuration);
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}
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public void setCentered(boolean centered) {
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mCentered = centered;
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invalidate();
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}
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public boolean isCentered() {
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return mCentered;
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}
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public void setUnselectedColor(int unselectedColor) {
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mPaintUnselected.setColor(unselectedColor);
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invalidate();
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}
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public int getUnselectedColor() {
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return mPaintUnselected.getColor();
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}
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public void setSelectedColor(int selectedColor) {
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mPaintSelected.setColor(selectedColor);
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invalidate();
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}
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public int getSelectedColor() {
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return mPaintSelected.getColor();
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}
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public void setLineWidth(float lineWidth) {
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this.mLineWidth = lineWidth;
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invalidate();
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}
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int screenWidth;
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public void setScreenWidth(int screenWidth) {
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this.screenWidth = screenWidth;
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invalidate();
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}
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public float getLineWidth() {
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return mLineWidth;
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}
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public void setStrokeWidth(float lineHeight) {
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mPaintSelected.setStrokeWidth(lineHeight);
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mPaintUnselected.setStrokeWidth(lineHeight);
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invalidate();
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}
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public float getStrokeWidth() {
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return mPaintSelected.getStrokeWidth();
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}
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public void setGapWidth(float gapWidth) {
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mGapWidth = gapWidth;
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invalidate();
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}
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public float getGapWidth() {
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return mGapWidth;
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}
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@Override
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protected void onDraw(Canvas canvas) {
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super.onDraw(canvas);
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if (mViewPager == null) {
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return;
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}
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final int count = mViewPager.getAdapter().getCount();
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if (count == 0) {
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return;
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}
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if (mCurrentPage >= count) {
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setCurrentItem(count - 1);
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return;
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}
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final float page = mViewPager.getAdapter().getCount();
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if (mViewPager.getAdapter().getCount() != 0
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&& mViewPager.getAdapter().getCount() > 0) {
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mLineWidth = screenWidth / page - mGapWidth * ((page - 2) / page);
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}
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final float lineWidthAndGap = mLineWidth + mGapWidth;
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final float indicatorWidth = screenWidth;
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final float paddingTop = getPaddingTop();
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final float paddingLeft = getPaddingLeft();
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final float paddingRight = getPaddingRight();
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float verticalOffset = paddingTop
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+ ((getHeight() - paddingTop - getPaddingBottom()) / 2.0f);
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float horizontalOffset = paddingLeft;
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if (mCentered) {
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horizontalOffset += ((getWidth() - paddingLeft - paddingRight) / 2.0f)
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- (indicatorWidth / 2.0f);
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}
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// Draw stroked circles
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for (int i = 0; i < count; i++) {
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float dx1 = horizontalOffset + (i * lineWidthAndGap);
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float dx2 = dx1 + mLineWidth;
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canvas.drawLine(dx1, verticalOffset, dx2, verticalOffset,
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(i == mCurrentPage) ? mPaintSelected : mPaintUnselected);
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}
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}
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public boolean onTouchEvent(android.view.MotionEvent ev) {
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if (super.onTouchEvent(ev)) {
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return true;
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}
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if ((mViewPager == null) || (mViewPager.getAdapter().getCount() == 0)) {
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return false;
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}
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final int action = ev.getAction() & MotionEventCompat.ACTION_MASK;
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switch (action) {
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case MotionEvent.ACTION_DOWN:
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mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
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mLastMotionX = ev.getX();
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break;
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case MotionEvent.ACTION_MOVE: {
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final int activePointerIndex = MotionEventCompat.findPointerIndex(
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ev, mActivePointerId);
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final float x = MotionEventCompat.getX(ev, activePointerIndex);
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final float deltaX = x - mLastMotionX;
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if (!mIsDragging) {
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if (Math.abs(deltaX) > mTouchSlop) {
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mIsDragging = true;
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}
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}
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if (mIsDragging) {
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mLastMotionX = x;
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if (mViewPager.isFakeDragging() || mViewPager.beginFakeDrag()) {
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mViewPager.fakeDragBy(deltaX);
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}
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}
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break;
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}
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case MotionEvent.ACTION_CANCEL:
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case MotionEvent.ACTION_UP:
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if (!mIsDragging) {
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final int count = mViewPager.getAdapter().getCount();
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final int width = getWidth();
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final float halfWidth = width / 2f;
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final float sixthWidth = width / 6f;
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if ((mCurrentPage > 0) && (ev.getX() < halfWidth - sixthWidth)) {
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if (action != MotionEvent.ACTION_CANCEL) {
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mViewPager.setCurrentItem(mCurrentPage - 1);
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}
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return true;
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} else if ((mCurrentPage < count - 1)
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&& (ev.getX() > halfWidth + sixthWidth)) {
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if (action != MotionEvent.ACTION_CANCEL) {
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mViewPager.setCurrentItem(mCurrentPage + 1);
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}
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return true;
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}
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}
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mIsDragging = false;
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mActivePointerId = INVALID_POINTER;
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if (mViewPager.isFakeDragging())
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mViewPager.endFakeDrag();
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break;
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case MotionEventCompat.ACTION_POINTER_DOWN: {
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final int index = MotionEventCompat.getActionIndex(ev);
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mLastMotionX = MotionEventCompat.getX(ev, index);
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mActivePointerId = MotionEventCompat.getPointerId(ev, index);
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break;
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}
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case MotionEventCompat.ACTION_POINTER_UP:
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final int pointerIndex = MotionEventCompat.getActionIndex(ev);
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final int pointerId = MotionEventCompat.getPointerId(ev,
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pointerIndex);
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if (pointerId == mActivePointerId) {
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final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
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mActivePointerId = MotionEventCompat.getPointerId(ev,
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newPointerIndex);
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}
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mLastMotionX = MotionEventCompat.getX(ev,
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MotionEventCompat.findPointerIndex(ev, mActivePointerId));
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break;
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}
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return true;
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}
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@Override
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public void setViewPager(ViewPager viewPager) {
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if (mViewPager == viewPager) {
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return;
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}
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if (mViewPager != null) {
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// Clear us from the old pager.
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mViewPager.setOnPageChangeListener(null);
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}
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if (viewPager.getAdapter() == null) {
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throw new IllegalStateException(
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"ViewPager does not have adapter instance.");
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}
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mViewPager = viewPager;
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mViewPager.setOnPageChangeListener(this);
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invalidate();
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}
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@Override
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public void setViewPager(ViewPager view, int initialPosition) {
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setViewPager(view);
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setCurrentItem(initialPosition);
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}
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@Override
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public void setCurrentItem(int item) {
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if (mViewPager == null) {
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throw new IllegalStateException("ViewPager has not been bound.");
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}
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mViewPager.setCurrentItem(item);
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mCurrentPage = item;
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invalidate();
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}
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@Override
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public void notifyDataSetChanged() {
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invalidate();
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}
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@Override
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public void onPageScrollStateChanged(int state) {
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if (mListener != null) {
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mListener.onPageScrollStateChanged(state);
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}
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}
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@Override
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public void onPageScrolled(int position, float positionOffset,
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int positionOffsetPixels) {
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if (mListener != null) {
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mListener.onPageScrolled(position, positionOffset,
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positionOffsetPixels);
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}
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}
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@Override
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public void onPageSelected(int position) {
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mCurrentPage = position;
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invalidate();
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if (mListener != null) {
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mListener.onPageSelected(position);
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}
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}
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@Override
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public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
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mListener = listener;
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}
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@Override
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protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
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setMeasuredDimension(measureWidth(widthMeasureSpec),
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measureHeight(heightMeasureSpec));
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}
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/**
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* Determines the width of this view
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*
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* @param measureSpec A measureSpec packed into an int
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* @return The width of the view, honoring constraints from measureSpec
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*/
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private int measureWidth(int measureSpec) {
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float result;
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int specMode = MeasureSpec.getMode(measureSpec);
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int specSize = MeasureSpec.getSize(measureSpec);
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if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) {
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// We were told how big to be
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result = specSize;
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} else {
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// Calculate the width according the views count
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final int count = mViewPager.getAdapter().getCount();
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result = getPaddingLeft() + getPaddingRight()
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+ (count * mLineWidth) + ((count - 1) * mGapWidth);
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// Respect AT_MOST value if that was what is called for by
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// measureSpec
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if (specMode == MeasureSpec.AT_MOST) {
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result = Math.min(result, specSize);
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}
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}
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return (int) Math.ceil(result);
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}
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/**
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* Determines the height of this view
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*
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* @param measureSpec A measureSpec packed into an int
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* @return The height of the view, honoring constraints from measureSpec
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*/
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private int measureHeight(int measureSpec) {
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float result;
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int specMode = MeasureSpec.getMode(measureSpec);
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int specSize = MeasureSpec.getSize(measureSpec);
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if (specMode == MeasureSpec.EXACTLY) {
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// We were told how big to be
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result = specSize;
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} else {
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// Measure the height
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result = mPaintSelected.getStrokeWidth() + getPaddingTop()
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+ getPaddingBottom();
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// Respect AT_MOST value if that was what is called for by
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// measureSpec
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if (specMode == MeasureSpec.AT_MOST) {
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result = Math.min(result, specSize);
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}
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}
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return (int) Math.ceil(result);
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}
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@Override
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public void onRestoreInstanceState(Parcelable state) {
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SavedState savedState = (SavedState) state;
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super.onRestoreInstanceState(savedState.getSuperState());
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mCurrentPage = savedState.currentPage;
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requestLayout();
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}
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@Override
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public Parcelable onSaveInstanceState() {
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Parcelable superState = super.onSaveInstanceState();
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SavedState savedState = new SavedState(superState);
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savedState.currentPage = mCurrentPage;
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return savedState;
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}
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static class SavedState extends BaseSavedState {
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int currentPage;
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public SavedState(Parcelable superState) {
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super(superState);
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}
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private SavedState(Parcel in) {
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super(in);
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currentPage = in.readInt();
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}
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@Override
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public void writeToParcel(Parcel dest, int flags) {
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super.writeToParcel(dest, flags);
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dest.writeInt(currentPage);
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}
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@SuppressWarnings("UnusedDeclaration")
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public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() {
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@Override
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public SavedState createFromParcel(Parcel in) {
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return new SavedState(in);
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}
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@Override
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public SavedState[] newArray(int size) {
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return new SavedState[size];
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}
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};
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}
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}
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