/*
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* Copyright (C) 2013 Leszek Mzyk
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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 cn.sinata.xldutils.widget.autoscoll;
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import android.os.Parcelable;
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import android.util.SparseArray;
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import android.view.View;
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import android.view.ViewGroup;
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import androidx.fragment.app.FragmentPagerAdapter;
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import androidx.fragment.app.FragmentStatePagerAdapter;
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import androidx.viewpager.widget.PagerAdapter;
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/**
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* A PagerAdapter wrapper responsible for providing a proper page to
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* LoopViewPager
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*
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* This class shouldn't be used directly
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*/
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public class LoopPagerAdapterWrapper extends PagerAdapter {
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private PagerAdapter mAdapter;
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private SparseArray<ToDestroy> mToDestroy = new SparseArray<ToDestroy>();
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private static final boolean DEFAULT_BOUNDARY_CASHING = true;
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private static final boolean DEFAULT_BOUNDARY_LOOPING = true;
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private boolean mBoundaryCaching = DEFAULT_BOUNDARY_CASHING;
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private boolean mBoundaryLooping = DEFAULT_BOUNDARY_LOOPING;
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void setBoundaryCaching(boolean flag) {
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mBoundaryCaching = flag;
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}
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void setBoundaryLooping(boolean flag) {
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mBoundaryLooping = flag;
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}
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LoopPagerAdapterWrapper(PagerAdapter adapter) {
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this.mAdapter = adapter;
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}
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@Override
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public void notifyDataSetChanged() {
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mToDestroy = new SparseArray<ToDestroy>();
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super.notifyDataSetChanged();
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}
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int toRealPosition(int position) {
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int realPosition = position;
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int realCount = getRealCount();
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if (realCount == 0)
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return 0;
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if (mBoundaryLooping) {
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realPosition = (position - 1) % realCount;
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if (realPosition < 0)
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realPosition += realCount;
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}
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return realPosition;
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}
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public int toInnerPosition(int realPosition) {
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int position = (realPosition + 1);
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return mBoundaryLooping ? position : realPosition;
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}
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private int getRealFirstPosition() {
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return mBoundaryLooping ? 1 : 0;
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}
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private int getRealLastPosition() {
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return getRealFirstPosition() + getRealCount() - 1;
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}
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@Override
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public int getCount() {
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int count = getRealCount();
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return mBoundaryLooping ? count + 2 : count;
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}
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public int getRealCount() {
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return mAdapter.getCount();
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}
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public PagerAdapter getRealAdapter() {
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return mAdapter;
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}
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@Override
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public Object instantiateItem(ViewGroup container, int position) {
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int realPosition = (mAdapter instanceof FragmentPagerAdapter || mAdapter instanceof FragmentStatePagerAdapter) ? position
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: toRealPosition(position);
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if (mBoundaryCaching) {
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ToDestroy toDestroy = mToDestroy.get(position);
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if (toDestroy != null) {
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mToDestroy.remove(position);
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return toDestroy.object;
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}
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}
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return mAdapter.instantiateItem(container, realPosition);
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}
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@Override
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public void destroyItem(ViewGroup container, int position, Object object) {
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int realFirst = getRealFirstPosition();
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int realLast = getRealLastPosition();
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int realPosition = (mAdapter instanceof FragmentPagerAdapter || mAdapter instanceof FragmentStatePagerAdapter) ? position
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: toRealPosition(position);
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if (mBoundaryCaching && (position == realFirst || position == realLast)) {
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mToDestroy.put(position, new ToDestroy(container, realPosition, object));
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} else {
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mAdapter.destroyItem(container, realPosition, object);
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}
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}
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/*
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* Delegate rest of methods directly to the inner adapter.
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*/
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@Override
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public void finishUpdate(ViewGroup container) {
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mAdapter.finishUpdate(container);
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}
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@Override
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public boolean isViewFromObject(View view, Object object) {
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return mAdapter.isViewFromObject(view, object);
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}
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@Override
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public void restoreState(Parcelable bundle, ClassLoader classLoader) {
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mAdapter.restoreState(bundle, classLoader);
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}
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@Override
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public Parcelable saveState() {
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return mAdapter.saveState();
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}
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@Override
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public void startUpdate(ViewGroup container) {
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mAdapter.startUpdate(container);
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}
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@Override
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public void setPrimaryItem(ViewGroup container, int position, Object object) {
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mAdapter.setPrimaryItem(container, position, object);
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}
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/*
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* End delegation
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*/
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/**
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* Container class for caching the boundary views
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*/
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static class ToDestroy {
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ViewGroup container;
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int position;
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Object object;
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public ToDestroy(ViewGroup container, int position, Object object) {
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this.container = container;
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this.position = position;
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this.object = object;
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}
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}
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}
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