/* Copyright (c) 2011-2013 Tang Ke
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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.wpc.library.widget.SlideMenu.utils;
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import androidx.viewpager.widget.PagerAdapter;
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import androidx.viewpager.widget.ViewPager;
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import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
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import android.view.View;
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import android.webkit.WebView;
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import android.widget.HorizontalScrollView;
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import java.lang.reflect.InvocationTargetException;
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import java.lang.reflect.Method;
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import java.util.WeakHashMap;
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/**
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* Provide base implements of {@link ViewPager}, {@link HorizontalScrollView},
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* {@link WebView} scroll detect, You can use {@link ScrollDetectorFactory} to
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* add your own implements of {@link ScrollDetector}
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*
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* @author Tank
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*
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*/
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public class ScrollDetectors {
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private static final WeakHashMap<Class<? extends View>, ScrollDetector> IMPLES = new WeakHashMap<Class<? extends View>, ScrollDetector>();
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private static ScrollDetectorFactory mFactory;
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/**
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* Check the view is horizontal scrollable
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*
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* @param v
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* @param direction
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* @return
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*/
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public static boolean canScrollHorizontal(View v, int direction) {
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ScrollDetector imples = getImplements(v);
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if (null == imples) {
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return false;
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}
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return imples.canScrollHorizontal(v, direction);
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}
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/**
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* Check the view is vertical scrollable
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*
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* @param v
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* @param direction
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* @return
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*/
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public static boolean canScrollVertical(View v, int direction) {
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ScrollDetector imples = getImplements(v);
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if (null == imples) {
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return false;
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}
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return imples.canScrollVertical(v, direction);
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}
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private static ScrollDetector getImplements(View v) {
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Class<? extends View> clazz = v.getClass();
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ScrollDetector imple = IMPLES.get(clazz);
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if (null != imple) {
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return imple;
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}
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if (v instanceof ViewPager) {
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imple = new ViewPagerScrollDetector();
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} else if (v instanceof HorizontalScrollView) {
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imple = new HorizontalScrollViewScrollDetector();
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} else if (v instanceof WebView) {
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imple = new WebViewScrollDetector();
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} else if (v instanceof SwipeRefreshLayout) {
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imple = new SwipeRefreshLayoutScrollDetector();
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} else if (null != mFactory) {
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imple = mFactory.newScrollDetector(v);
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} else {
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return null;
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}
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IMPLES.put(clazz, imple);
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return imple;
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}
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/**
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* Base implements of {@link ScrollDetector} for {@link ViewPager}
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*
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* @author Tank
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*
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*/
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private static class ViewPagerScrollDetector implements ScrollDetector {
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@Override
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public boolean canScrollHorizontal(View v, int direction) {
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ViewPager viewPager = (ViewPager) v;
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PagerAdapter pagerAdapter = viewPager.getAdapter();
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if (null == pagerAdapter || 0 == pagerAdapter.getCount()) {
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return false;
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}
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final int currentItem = viewPager.getCurrentItem();
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return (direction < 0 && currentItem < pagerAdapter.getCount() - 1)
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|| (direction > 0 && currentItem > 0);
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}
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@Override
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public boolean canScrollVertical(View v, int direction) {
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// TODO
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return false;
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}
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}
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/**
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* Base implements of {@link ScrollDetector} for {@link WebView}
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*
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* @author Tank
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*
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*/
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private static class WebViewScrollDetector implements ScrollDetector {
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@Override
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public boolean canScrollHorizontal(View v, int direction) {
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try {
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// Because this method is protected
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Method computeHorizontalScrollOffsetMethod = WebView.class
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.getDeclaredMethod("computeHorizontalScrollOffset");
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Method computeHorizontalScrollRangeMethod = WebView.class
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.getDeclaredMethod("computeHorizontalScrollRange");
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computeHorizontalScrollOffsetMethod.setAccessible(true);
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computeHorizontalScrollRangeMethod.setAccessible(true);
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final int horizontalScrollOffset = (Integer) computeHorizontalScrollOffsetMethod
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.invoke(v);
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final int horizontalScrollRange = (Integer) computeHorizontalScrollRangeMethod
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.invoke(v);
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return (direction > 0 && v.getScrollX() > 0)
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|| (direction < 0 && horizontalScrollOffset < horizontalScrollRange
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- v.getWidth());
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} catch (NoSuchMethodException e) {
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e.printStackTrace();
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} catch (IllegalArgumentException e) {
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e.printStackTrace();
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} catch (IllegalAccessException e) {
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e.printStackTrace();
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} catch (InvocationTargetException e) {
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e.printStackTrace();
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}
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return false;
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}
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@Override
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public boolean canScrollVertical(View v, int direction) {
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// TODO
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return false;
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}
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}
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/**
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* Base implements of {@link ScrollDetector} for
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* {@link HorizontalScrollView}
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*
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* @author Tank
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*
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*/
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private static class HorizontalScrollViewScrollDetector implements
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ScrollDetector {
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@Override
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public boolean canScrollHorizontal(View v, int direction) {
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HorizontalScrollView horizontalScrollView = (HorizontalScrollView) v;
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final int scrollX = horizontalScrollView.getScrollX();
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// Without scroll wrapper, can't scroll
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if (0 == horizontalScrollView.getChildCount()) {
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return false;
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}
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return (direction < 0 && scrollX < horizontalScrollView.getChildAt(
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0).getWidth()
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- horizontalScrollView.getWidth())
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|| (direction > 0 && scrollX > 0);
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}
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@Override
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public boolean canScrollVertical(View v, int direction) {
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// TODO
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return false;
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}
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}
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private static class SwipeRefreshLayoutScrollDetector implements
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ScrollDetector {
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@Override
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public boolean canScrollHorizontal(View v, int direction) {
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return false;
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}
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@Override
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public boolean canScrollVertical(View v, int direction) {
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return true;
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}
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}
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/**
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* Factory for create new scroll detector
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*
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* @param factory
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*/
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public static void setScrollDetectorFactory(ScrollDetectorFactory factory) {
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mFactory = factory;
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}
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/**
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*
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* @author Tank
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*
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*/
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public interface ScrollDetector {
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boolean canScrollHorizontal(View v, int direction);
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boolean canScrollVertical(View v, int direction);
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}
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}
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